# Lane's Corner - One Tech's Blog



## Lane Sparber

Hello again, everyone!

After seeing several posts about shielding your guitar and the various methods involved (as well as being asked directly to contribute my methods), I thought I’d share a step-by-step detailed analysis of how I perform this job in my shop. My way is NOT the only way to do this job - it’s just the method that I personally use and has worked best for me as I developed it over time. Recently, I was given a noisy mongrel guitar (based on a Fender Jaguar…sort of) that had two AWESOME sounding P-90 pickups in it but was excessively noisy. Time for a shielding job!

For your collective consideration, I'd like to insert a quick word on what shielding will and will not do. It WILL block almost all RF interference if done correctly, as we’re in effect forming a Faraday cage around all of the guitar’s internal components. This silences the guitar to a considerable degree…even on humbucker equipped instruments. If you do your job right, you may even disconnect the ground wire to the bridge, as it will serve no purpose anymore. That being said, I usually do leave it connected as a personal preference. There should be no more annoying buzz when you take your fingers off of the strings, and the signal-to-noise ratio will be drastically improved. What shielding WON’T do is remove the 60 cycle hum completely from single coil pickups…that’s just not possible. However there will be a DRASTIC reduction of noise, so this process is, of course, especially effective on Strats and single coil equipped guitars. Also, this process is non-reversible if you use shielding paint, so that's also a consideration on vintage instruments (although Stevie Ray Vaughan had all of his Strats shielded in this manner...so there's an endorsement for you!).

A lot of guitars come from the factory with no shielding at all, or sub-standard work that will not accomplish much of anything. For maximum effectiveness, ALL control cavities, control cavity covers and pickuguards must be uniformly coated with either shielding paint (a special paint that actually conducts electricity) or aluminum/copper foil tape and then connected to ground. The supplies we need are pretty basic. First, we’ll need shielding paint, obviously. I get mine from Stewart MacDonald Guitar Shop Supply (it’s water based, so cleanup is fairly easy). Keep some wet and dry paper towels handy in case you go outside the lines for cleanup. You can find the paint here, or on eBay:

STEWMAC.COM : Conductive Shielding Paint 

I have an old roll of aluminum foil tape that I use, but Stew-Mac sells great copper tape here:

STEWMAC.COM : Conductive Copper Tape

You’ll also need a couple of junk paintbrushes to apply the paint, and keep them ONLY for this purpose.

Also, I use a #11 eXacto blade to trim the foil once it’s on the pickguard/control cavity cover.

Here’s a pic of my main shielding tools:






Additionally, you may need ground lugs, wire, drill and short wood screws (I’ll describe when and why you may need these below).

Now, as a rule I ONLY use the foil tape for pickguards and control cavity covers, NOT the cavities themselves, although many people use the foil there too. My issue with doing it that way is that the foil tape can come loose from the cavity walls overt time and short out the guitar. Also, it’s VERY time consuming to cut, paste and solder all of that foil. Although the shielding paint requires two coats and must dry overnight after each coat, the actual labor time involved is under an hour once you get it down. 

Here’s the body of the subject we’re dealing with today. Note that ABSOLUTELY NO shielding inside the body has been done at the factory. The remaining wire inside is the ground to bridge, which, as I said, I leave in, although you can remove it once the shielding job is complete.






Here’s the pickguard…note the minimal aluminum foil applied to the back of the guard…just enough to cover the components, but NOT the rest of the electronics routing below it - or even the pickup selector switch (already removed here) to the left:






First, I paint the first coat of shielding paint into the guitar body, and ALL cavities (front or back) that contain electronics get shielded. TAKE YOUR TIME AND HAVE PATIENCE!! Neatness counts – especially on something like a J Bass where the back pickup has no pickguard over the rear pickup to cover your mess. Here we are after the first coat while the paint is still wet:






Now on to the pickguard. I am only going to shield the bottom 1/3 or so of this pickguard. The portions of the ‘guard that just lie flat against the body don’t need to be shielded for obvious reasons. We only need to concern ourselves with what goes over the electronics. I lay the guard over a scrap piece of cardboard and apply the tape. Once that’s done, I trim the excess foil tape GENTLY along the edges and all of the holes in the guard with the eXacto blade. Here’s the pickguard with it’s new shielding job (and the sloppy factory lead dress cleaned up considerably):






If you have a Strat or P Bass, complete pickguard shields are readily available online, and you can skip this step entirely. You can find them here:

Pickguard Shield at Guitar Center. | Search Results

Once the second coat is in and all paint is dry, any cavities not directly connected to the main cavity need to be connected to ground. For example, a typical Strat uses one big rout, so you won’t need this step. Our subject guitar here has two pickup routs that are separate from the main rout, so this guitar will need two of these additional ground wires. For this purpose, I assemble lugs that are crimped AND soldered to new ground wires, and then I screw them into the base of the cavity itself. Finally, I run those wires directly to ground connections on the pots. BE EXTREMELY CAREFUL HERE. If you use screws that are too long, you can go through the back of the guitar with them, so measure carefully and then measure again. Also, drilling pilot holes for these screws is highly recommended. Here’s a picture of this step completed:






Now, the main cavity needs to be connected directly to ground as well. This can be done three ways: 1) Use a grounding lug screwed into the body as we did above, 2) Paint up onto the guitar body’s face with some extra paint in a manner that connects to the pickguard’s foil shield, or 3) take a strip of your foil tape and overlap it onto the guitar’s top where it will contact the pickguard's shielding tape. I usually choose option 3 to save drilling another hole or painting onto the guitar’s face:






Finally, wire it all together and test fit it all together to make sure nothing’s touching the control cavity walls and shorting out. Plug it in and test all functions and switches to make sure everything works as it should. Here’s this guitar wired up and ready for test fitting:






All assembled here. It’s passed all noise tests, wiring tests, and is ready for the neck to be re-attached and it's final set up:






Here we are…all ready to go back to the customer!






Anyway, I hope some of you found this informative, and I invite one and all to share their questions, tips, individual methods, rants, and tricks below. Happy shielding…and, most importantly, HAVE FUN WITH IT! 

-Lane


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## Lespaulnmarshall

*Re: Shielding Your Guitar - One Tech's Methods - With Photos!*

Thanks!!! This thread should become a sticky just like the wax potting thread.


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## IbanezMark

*Re: Shielding Your Guitar - One Tech's Methods - With Photos!*

Thanks Lane!


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## Lane Sparber

*Re: Shielding Your Guitar - One Tech's Methods - With Photos!*

Thanks, guys!  Just doing as I was asked.

Cheers!

-Lane


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## Alabama Thunderpussy

*Re: Shielding Your Guitar - One Tech's Methods - With Photos!*

Awesome post! I shielded the inside of my LP's cavity with the aluminum shielding that already had the adhesive on it. I love that stuff.


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## thetragichero

*Re: Shielding Your Guitar - One Tech's Methods - With Photos!*

i use the copper foil tape with the conductive adhesive
when i do the body, i'll leave a little lip over the top edge to make sure it'll come into contact with the foil on the pickguard
generally, i'll also star ground all of the ground wires to one of the pickguard screws


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## ckr1231

*Re: Shielding Your Guitar - One Tech's Methods - With Photos!*

What affect does it have on Controllable feedback? Does it make it harder to derive the feedback?


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## cagamp1

*Re: Shielding Your Guitar - One Tech's Methods - With Photos!*

Great tutorial Lane!


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## Lane Sparber

*Re: Shielding Your Guitar - One Tech's Methods - With Photos!*



ckr1231 said:


> What affect does it have on Controllable feedback? Does it make it harder to derive the feedback?



It has no effect on controllable feedback, other than to provide a lower noise floor for the notes to swell from. RF interference and controllable feedback are two separate things. 

-Lane


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## MM54

*Re: Shielding Your Guitar - One Tech's Methods - With Photos!*

Fantastic job, Lane! Once I get some money in the bank after christmas I'll definitely be shielding my LP... it's rather noisy. Maybe I'll do my Cort, too. It's not as bad, but could be quieter.

Thanks!


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## Australian

*Re: Shielding Your Guitar - One Tech's Methods - With Photos!*

a great thread. thanks.


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## wkcchampion

*Re: Shielding Your Guitar - One Tech's Methods - With Photos!*

Cool. IS it useful for humbuckers too?


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## Lane Sparber

*Re: Shielding Your Guitar - One Tech's Methods - With Photos!*



wkcchampion said:


> Cool. IS it useful for humbuckers too?



It's useful for any guitar, really. It just quiets down humbucker-equipped guitars even further.

-Lane


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## rustyrat

*Re: Shielding Your Guitar - One Tech's Methods - With Photos!*

question: none of my guitars buzz at all. My amp is dead quiet even at high gain and volume. Not sure I understand this. I dont even understand waxing the pups. I have never had this type of issue. Could someone enlighten me, maybe I'm missing something or just deaf! 
Thanks
RR


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## Lane Sparber

*Re: Shielding Your Guitar - One Tech's Methods - With Photos!*



rustyrat said:


> question: none of my guitars buzz at all. My amp is dead quiet even at high gain and volume. Not sure I understand this. I dont even understand waxing the pups. I have never had this type of issue. Could someone enlighten me, maybe I'm missing something or just deaf!
> Thanks
> RR



Don't know what to tell you, other than ENJOY IT! If your rig is quiet and you are happy with it, don't do anything to it...or worry about it. Rock on!

-Lane


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## rustyrat

*Re: Shielding Your Guitar - One Tech's Methods - With Photos!*



Lane Sparber said:


> Don't know what to tell you, other than ENJOY IT! If your rig is quiet and you are happy with it, don't do anything to it...or worry about it. Rock on!
> 
> -Lane


Thanks Lane! 
RR


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## ckr1231

*Re: Shielding Your Guitar - One Tech's Methods - With Photos!*

Should the back spring cavity of a Strat be shielded as well ?


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## thrawn86

*Re: Shielding Your Guitar - One Tech's Methods - With Photos!*

Great topic Lane. You're a class act here on the Forum.


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## Lane Sparber

*Re: Shielding Your Guitar - One Tech's Methods - With Photos!*



ckr1231 said:


> Should the back spring cavity of a Strat be shielded as well ?



Not at all. There are no electronics or anything connected to the "hot" lead back there, just the wire to the spring claw for the bridge ground. Thus, you can forget about shielding that one.

@Thrawn - THANKS MAN! That's quite the compliment, and not taken lightly!



-Lane


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## ckr1231

*Re: Shielding Your Guitar - One Tech's Methods - With Photos!*

Thank you, sir. Awesome thread !!!!!


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## Georgiatec

*Re: Shielding Your Guitar - One Tech's Methods - With Photos!*

Lane...you are a top guy...cue the next job on my Strats next time I change the strings...the ones with vintage noiseless pups in are pretty quiet, but from what you say it's a no lose situation to do it anyway.


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## DSL100 Dude

*Re: Shielding Your Guitar - One Tech's Methods - With Photos!*

Excellent post! 
Thanks for contributing this. What a great tutorial for us DIY guys. I have a Strat that I look forward to trying this out on.


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## Lane Sparber

*Re: Shielding Your Guitar - One Tech's Methods - With Photos!*

Thanks again for the compliments!! That reminds me, guys...if you do your Strats, think twice about shielding the small oval cavity where the jack sits. If you do so, upon re-installation, you'll have to carefully rotate the actual jack in it's holder until it doesn't make any contact with the side walls. These jacks sometimes contact the sides of the cavity when a cable is inserted, which will then short out once the hot lug touches the now grounded sides of the cavity.

Cheers!


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## All4Tone

*Re: Shielding Your Guitar - One Tech's Methods - With Photos!*

Well, I went on a quest yesterday to find something to shield one of my strats with and if you want to see a 'deer-in-the-headlights' look, just go into Home Depot and ask if they have any shielding paint..

I ended up just buying some aluminum foil tape - 175 feet of it actually!

I grabbed a MIM Strat and just loosened the strings and held them up off the fretboard by stuffing a small block of wood under them at the 12th fret. I then removed the screws for the pickguard and lifted it out carefully and set it aside.

The next bit was actually way easier than I thought it would be, but I tore pieces of the tape off the roll and peeled the backing off and just started meticulously laying it on all inside surfaces of the cavities.

I did all surfaces of all cavities on the front of the guitar, then used a DMM to test for continuity from any 2 points on the foil. It was all electrically connected, which kind of surprised me, as there is the adhesive on the foil. Once I was all done with the tape, I ran a piece of bare copper wire between all the cavities and taped it down with the foil tape, so it's pretty much invisible, but everything is very positively connected, even though I already confirmed that with the meter.

The pickguard on this guitar is one of those really cheap, but amazingly good Dragonfire loaded pickguards (there's another whole discussion for you) and they do a much better job of shielding than most factory shielding attempts, but I added more in various places on the pickguard. I never swap pickups btw, just whole pickguards, it's way quicker and easier and I can preload it any way I like on the bench, then swap it in 5 minutes.

I used a piece of duct tape on the inside of the oval jack cavity, on top of the foil tape, just to avoid the situation described above with the jack or plug shorting out on the foil.

In a couple of spots on either side of the guitar, I let the shielding go very slightly up onto the face of the guitar (like about 1mm), so the pickguard shielding would contact it in a few places, even though that is probably not really necessary.

After I reassembled and tuned it up, here is what I found.

No RF picked up by any pups, but that 60hz hum that we all know and love with single coils is still there and no amount of shielding will stop that.

The humbucker in the bridge and the positions 2 and 4 on the pup selector switch (the paired pups are wired out of phase) is dead quiet now, but to be honest, it always was, so did I gain anything? Probably, but on my next one, I'll do before and after recordings and photos. 

Lane, thanks again, you've inspired me to attack this issue on a few of my guitars..


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## Lane Sparber

*Re: Shielding Your Guitar - One Tech's Methods - With Photos!*

Wow! Thanks for the detailed report. Shielding is supposed to JUST get rid of the RF hum as I said above, and the 60 cycle hum will always be there. You should find that you can let go of the strings now completely and there will be no more buzz when you do, as well as a quieter noise floor over all.

Congrats! 

-Lane


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## diesect20022000

*Re: Shielding Your Guitar - One Tech's Methods - With Photos!*

great tips as usual! I have been shielding for awhile but, it's nice to see some things i may have mossed and the paint shielding's one i have yet to apply.


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## Dirt Rich

*Re: Shielding Your Guitar - One Tech's Methods - With Photos!*

Thanks for the great tutorial! Looks like a have a few guitars to tear apart...


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## Lane Sparber

*A Few Months in the Life Of...*

Hey, folks!

With all of the other techs around here routinely posting awesome examples of their work (JCM, Major, Wilder, Joey, Alabama, etc.), it has made me realize that, other than a couple of how-to threads, I have been sadly deficient in this area.

So, to that end, it's time to put my money where my mouth is, so to speak. Below is a link to the "Lane's Workshop" photo album on my Facebook page. It's a public link, so it should work (I hope). While this by no means represents EVERYTHING that's come through my shop in the last few months - I am far too lazy to photograph every piece of gear that I work on - I feel it's a pretty accurate representation of what I've been up to in my basement recently. It's my intention to update this fairly regularly, so please feel free to check back periodically for new exploits! 

Happy browsing!

Link:

Lane's Workshop | Facebook

-Lane


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## Joey Voltage

*Re: A Few Months in the Life Of...*

You run a tight ship there Lane.


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## TwinACStacks

*Re: A Few Months in the Life Of...*

 VERY cool Pics Bro. I work on my amps on top of my washing machine in the Basement, I wouldn't know how to act with a workbench....


 TWIN


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## Lane Sparber

*Re: A Few Months in the Life Of...*

THANKS, GUYS! Highest compliments indeed, given the sources...and not taken lightly.

I just do what I do and try to keep people in the business of making music. I'm glad you enjoyed the pics.



-Lane


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## Moose Lewis

*Re: A Few Months in the Life Of...*

Wow ~ nice work pix and Marshall porn! You look like a one-stop custom shop for guitars & amps. 

Only one complaint... _there's just too much space to work in_, lol. I have to almost feel claustrophobic before I'm comfortable. 
 Cheers!


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## chuckharmonjr

*Re: A Few Months in the Life Of...*

Very nice set-up Lane.


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## chuckharmonjr

*Re: A Few Months in the Life Of...*

LOL...Im with ya on that one Twin. I have a piece of 1x12 shelving that I stick on the mattress, and in conjunction with my night stand...thats where I do all my amp/guitar/pedal work. My DSL is a true 'bedroom' amp in the sense that everything Ive done to her was right there on the bed...lol.


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## Adwex

*Re: A Few Months in the Life Of...*

Good to see that there's someone in the NY area. I didn't get a warm and fuzzy feeling from a local guy I used recently.


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## Lane Sparber

*Re: A Few Months in the Life Of...*



Adwex said:


> Good to see that there's someone in the NY area. I didn't get a warm and fuzzy feeling from a local guy I used recently.



COOL! I'd be honored, Adwex! 

-Lane


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## guitarweasel

*Re: A Few Months in the Life Of...*

Wish my tech area was that organized. Nice work!


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## diesect20022000

*Re: A Few Months in the Life Of...*

very organized....i'm jealous,lol.


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## scat7s

*Re: A Few Months in the Life Of...*

clean AND bright....thats a nice space. is that in your home, or is it a commercial space? you do this work full time right lane? looks like a nice room to work in...


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## Lane Sparber

*Re: A Few Months in the Life Of...*

It's in my basement. It's my second job...where all the fun money comes from! I'm in here now recapping my DSL as I type this. Photos to go up eventually...

Also, yes, it is a VERY comfy room to work in. It HAS to be inviting, because I spend so much time here!

-Lane


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## tonefreak

*Re: A Few Months in the Life Of...*

damn. i wish my 'workshop' was that nice. i only do limited guitar work (AKA, everything but the fretboard... lol), but my workshop consists of a shop light hung over about a 2.5x6 table (with a homasote over plywood top... doesn't scratch the guitars) in the back of the furnace/freezer/hunting closet/random junk room in the basement.

with my bin/drawer units, pile of rags, a soldiering gun and pen, random junk, etc, there's barely enough room for a guitar!


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## Lane Sparber

*Re: A Few Months in the Life Of...*



tonefreak said:


> damn. i wish my 'workshop' was that nice. i only do limited guitar work (AKA, everything but the fretboard... lol), but my workshop consists of a shop light hung over about a 2.5x6 table (with a homasote over plywood top... doesn't scratch the guitars) in the back of the furnace/freezer/hunting closet/random junk room in the basement.
> 
> with my bin/drawer units, pile of rags, a soldiering gun and pen, random junk, etc, there's barely enough room for a guitar!



No worries! We all have to start somewhere. When we had our apartment, my "workshop" was the dining room table, and the wife constantly screamed at me that I was ruining her good tablecloths with wood shavings, soldering iron burn marks, and various other things! When we were shopping for a house, a nice, big workshop for my music stuff was a prerequisite...especially since it was also an easy way for her to get rid of me for hours at a time. 

-Lane


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## MartyStrat54

*Re: A Few Months in the Life Of...*

Great pictures. You are not a fake.


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## TwinACStacks

*Re: A Few Months in the Life Of...*

 It's pretty hard to Fuck up a Washing Machine, especially one that's 15 yrs old. You can get a Hell of a ground though.....


 TWIN


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## Lane Sparber

*Re: A Few Months in the Life Of...*



TwinACStacks said:


> It's pretty hard to Fuck up a Washing Machine, especially one that's 15 yrs old. You can get a Hell of a ground though.....
> 
> 
> TWIN



Well, the washing machines in my old apartment were communal in a big laundry room, so I'm pretty sure working in there on those machines would have gotten me into even MORE trouble! 

-Lane


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## TwinACStacks

*Re: A Few Months in the Life Of...*



Lane Sparber said:


> Well, the washing machines in my old apartment were communal in a big laundry room, so I'm pretty sure working in there on those machines would have gotten me into even MORE trouble!
> 
> -Lane



Definitely don't want to lose any excess resistor leads you may have snipped, into some Woman's Lingerie Load.

My Wife just Hates when I do that....

 TWIN


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## MM54

*Re: A Few Months in the Life Of...*

Very nice


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## Michael1987xl

*Re: A Few Months in the Life Of...*

Allow me to give my boy, Lane, some props here. 

Yes, he's obviously got the tools and he's got the talent, but more than either, he's got the temperament. Lane not only knows what whatever you bring him _should_ sound like when he's done. The only thing that exceeds his patience to see the job through is an innate desire to get it just right. When he wields his tools in that room, magic happens. 

You can't put a price on that kind of work, people. Believe it. My 1987xl has never been better, my brother's Fender Bassman 50 went from a hopeless case to a treasure and my Les Paul is so good, when I think about what I paid for it, it's almost criminal. If you're within _hours_ of driving to him, the trip is guaranteed to be worth it.

Now, having said that, Lane, *finish that DSL and fix my Scott!*


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## MajorNut1967

*Re: A Few Months in the Life Of...*



Adwex said:


> Good to see that there's someone in the NY area. I didn't get a warm and fuzzy feeling from a local guy I used recently.



Why, wasn't he a teddy bear?


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## chuckharmonjr

*Re: A Few Months in the Life Of...*



TwinACStacks said:


> Definitely don't want to lose any excess resistor leads you may have snipped, into some Woman's Lingerie Load.
> 
> My Wife just Hates when I do that....
> 
> TWIN



Twin you aint even tight Bro..lol...I done got a damned visual on the one....lol


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## CKCinMass

*Re: A Few Months in the Life Of...*



Lane Sparber said:


> ...especially since it was also an easy way for her to get rid of me for hours at a time.
> 
> -Lane



I just got rid of the wife and it was like hitting a noise reduction switch.......

worked for me......


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## chuckharmonjr

*Re: A Few Months in the Life Of...*

In the process of that meself CKC....and damn its gonna be better...lol...it'll be like taking a 250 lb shit after being constipated for 5 years...total relief


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## Joey Voltage

*Re: A Few Months in the Life Of...*

Sorry Lane, I'm gonna have to show you up on your own thread!


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## yladrd61

*Re: A Few Months in the Life Of...*

Nice work on that Fender Twin I sent you an FB add request


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## Lane Sparber

*Re: A Few Months in the Life Of...*



Joey Voltage said:


> Sorry Lane, I'm gonna have to show you up on your own thread!



Fer heaven's sake, Joey! Clean up that mess! 



-Lane


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## Alabama Thunderpussy

*Re: A Few Months in the Life Of...*

Lane your workspace is too modern. Joey yours is too hipster, with your PBR beer.

My ghetto bench.






Shit. We're all hijacking Lane's thread.


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## Lane Sparber

*Re: A Few Months in the Life Of...*

So I hate clutter...sue me (wait...if John from SoZo is reading this, please DON'T sue me)! 

Michael - thanks for the kind words, bro! The caps for your Scott have been ordered.

-Lane


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## diesect20022000

*Re: A Few Months in the Life Of...*



chuckharmonjr said:


> In the process of that meself CKC....and damn its gonna be better...lol...it'll be like taking a 250 lb shit after being constipated for 5 years...total relief


 man....that's only 50lbs less than i weigh...


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## CKCinMass

*Re: A Few Months in the Life Of...*



chuckharmonjr said:


> In the process of that meself CKC....and damn its gonna be better...lol...it'll be like taking a 250 lb shit after being constipated for 5 years...total relief



For me it was like the surgical removal of a parasitic mass attached to my bank account.....good luck with it.......I hope all goes well....


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## Lane Sparber

*Re: A Few Months in the Life Of...*

Look what I started here. Sigh. For the record, my wife is a keeper! Marrying her was one of the only decisions in my life that I DON'T regret. 

-Lane


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## CKCinMass

*Re: A Few Months in the Life Of...*



Lane Sparber said:


> Look what I started here. Sigh. For the record, my wife is a keeper! Marrying her was one of the only decisions in my life that I DON'T regret.
> 
> -Lane



Lane,

Sorry for the sour turn in direction.......just poking a lil fun at my own experience.....

Very nice work area! I can see why you are held in high regard.


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## Lane Sparber

*Re: A Few Months in the Life Of...*

No worries!

-Lane


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## Lane Sparber

Hello, everyone!

I have graciously been offered a sticky of my own for all of my tech articles and blogs about work I am doing in the field. I plan to update this thread occasionally with interesting repairs I do, procedures I've developed, and any other relevant or entertaining info I can provide about what I'm working on.

To that end, two of my other threads will be incorporated into this thread for starters...my "A Few Months In The Life Of..." thread and my "Shielding Your Guitar" thread in order to get the ball rolling.

I am flattered and humbled _beyond measure_ to be afforded this little soapbox, and I promise to never take that lightly or abuse the privilege.

Happy reading, friends!

-Lane


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## tresmarshallz

This forum is lucky to have you Lane and the time you dedicate to helping out. Your knowledge and attitude are exemplary, the kind of guy that any potential customer would like interacting with and be comfortable taking their gear to.


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## scat7s

congrats lane! look fwd to it


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## Alabama Thunderpussy

Lane, can you help me? I'm drawing a load line for an output section. I'll be using twenty-four KT88's. 

My goal is to see how many neighborhoods I can brown out with a single power chord.


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## Lane Sparber

Alabama Thunderpussy said:


> Lane, can you help me? I'm drawing a load line for an output section. I'll be using twenty-four KT88's.
> 
> My goal is to see how many neighborhoods I can brown out with a single power chord.





I'll get right on that! 

Thanks for the kind words everyone! I have a new blog in the works...hopefully it will be up soon.

-Lane


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## MajorNut1967

Now this sound's like a good deal! Good luck and look forward to it.


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## nedcronin

Great news and a great idea! I'm looking forward to this Lane...


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## Adwex

Lane Sparber said:


> Hello, everyone!
> 
> I have graciously been offered a sticky of my own for all of my tech articles and blogs about work I am doing in the field. I plan to update this thread occasionally with interesting repairs I do, procedures I've developed, and any other relevant or entertaining info I can provide about what I'm working on.
> 
> To that end, two of my other threads will be incorporated into this thread for starters...my "A Few Months In The Life Of..." thread and my "Shielding Your Guitar" thread in order to get the ball rolling.
> 
> I am flattered and humbled _beyond measure_ to be afforded this little soapbox, and I promise to never take that lightly or abuse the privilege.
> 
> Happy reading, friends!
> 
> -Lane



Sticky'd and merged.

Unfortunately when merged with the other existing threads, all posts are sorted chronologically, so your post introducing the merged blog appears on page 3 of the thread.


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## Lane Sparber

No worries! As long as all of the info is there, then that is all I can ask for! 

-Lane


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## TwinACStacks

OH GREAT. ANOTHER TECH POST....



Way to go Lane, congrats on your own Corner,

All they let me have was a thread.

 TWIN


----------



## MajorNut1967

TwinACStacks said:


> OH GREAT. ANOTHER TECH POST....
> 
> TWIN



That's my Brother Twin or My Twin Brother? One of the two anyway!


----------



## yladrd61

Going back to the subject of shielding. I was getting static through the speakers on my amp whenever I touched the pickguard {Singlre Ply } with my fingers. on my Fender SE '59 Reissue Thin Skin Nitro Stratocaster. I tried all kinds of stuff but the thing that made it stop was putting on a 3 ply pickguard, the 3 ply come with shielding tape on it and the 50s style single ply only had an aluminum plate between the pots and pickguard. The only other mod I have done is hooking the bridge pickup up to one of the tone controls and upgraded and added a second tone cap cap. Bridge{.1uf}, Neck,Middle {.047uf}.


----------



## MajorNut1967

Alabama Thunderpussy said:


> Lane, can you help me? I'm drawing a load line for an output section. I'll be using twenty-four KT88's.
> 
> My goal is to see how many neighborhoods I can brown out with a single power chord.



Hey why don't you us a couple of 4-1000A power tubes in a Push-pull AB1 configuration with plate voltage of 6KV and screens at 1KV, it will yield about 3840 watts per pair? Oh yeah the Heater voltage is only 7.5volts @ 21amps.


----------



## chuckharmonjr

Alabama Thunderpussy said:


> Lane, can you help me? I'm drawing a load line for an output section. I'll be using twenty-four KT88's.
> 
> My goal is to see how many neighborhoods I can brown out with a single power chord.



You better get some 4/0 to hook that shit up with, and a blowtorch to solder with....lol


----------



## Michael1987xl

Nice goin' Lane! Looking forward to reading more from you and learning a thing or three. Well done and congrats on the sticky.

Now, don't f* this up!


----------



## chuckharmonjr

Lane....sincere congratrulations....you absolutely deserve it.


----------



## cagamp1

Alabama Thunderpussy said:


> Lane, can you help me? I'm drawing a load line for an output section. I'll be using twenty-four KT88's.
> 
> My goal is to see how many neighborhoods I can brown out with a single power chord.


 


MajorNut1967 said:


> Hey why don't you us a couple of 4-1000A power tubes in a Push-pull AB1 configuration with plate voltage of 6KV and screens at 1KV, it will yield about 3840 watts per pair? Oh yeah the Heater voltage is only 7.5volts @ 21amps.


 

Are you guys trying to build one of them Nazi infrasound generator weapons?


----------



## MajorNut1967

cagamp1 said:


> Are you guys trying to build one of them Nazi infrasound generator weapons?



I would be up for that! You mean the _Wunder Waffe, Der Klang Kanone_? Definitely!


----------



## cagamp1

MajorNut1967 said:


> I would be up for that! You mean the _Wunder Waffe, Der Klang Kanone_? Definitely!


 
Not quite...those were soundless canons.

I tell you those Germans are masterminds. They came up with and started to developed a lot of stuff still unused today...except for stealth and flying saucers that is.

What I was refering to was a powerful low frequecy amplifier/generator developed to pulvarize and crumble anything and everything. My understanding is that it was in the development stages but they couldn't get past the channeling or isolation of waves. Basically everything around it started to crumble.

Check out its little great grand kid, the LRAD.

*Add: Sorry Lane, no more interruptions from me.*


----------



## eljeffebrown

Hey lane what are your prices like? is it by the hour or job? I really need to get my head recapped and basically serviced. and take a look at EXACTLY what my mod is. let me know man.


----------



## Wilder Amplification

Can we get a Nancy Grace sticky thread going here?


----------



## Lane Sparber

eljeffebrown said:


> Hey lane what are your prices like? is it by the hour or job? I really need to get my head recapped and basically serviced. and take a look at EXACTLY what my mod is. let me know man.



El Jeffe - just gimme a call to discuss. You have my number! 

-Lane


----------



## j2112c

Hey Lane congratulations on the sticky (good move Adwex).

You are real asset to the forum, you are knowledgable and as said before by one of the other guys you have a really good attitude/temperament another reason why you are rightly so popular here.


----------



## TwinACStacks

MajorNut1967 said:


> That's my Brother Twin or My Twin Brother? One of the two anyway!



 I Got Your Back Mate. We've got to stick together lest these kids take over OUR domain.

The Older you get the Tougher it is to be an Alpha Male.

Snot-nosed punks....

 TWIN


----------



## MajorNut1967

cagamp1 said:


> Not quite...those were soundless canons.
> 
> [/B]



What were soundless cannons? The one I was speaking of is called "_Der Klang Kanone_" which means "Sound Cannon" LOL


----------



## Joey Voltage

MajorNut1967 said:


> What were soundless cannons? The one I was speaking of is called "_Der Klang Kanone_" which means "Sound Cannon" LOL



I want to build the Bell


----------



## MajorNut1967

Joey Voltage said:


> I want to build the Bell



Okay I'll build the resonance chambers!


----------



## cagamp1

MajorNut1967 said:


> What were soundless cannons? The one I was speaking of is called "_Der Klang Kanone_" which means "Sound Cannon" LOL


 
I know. That is what is weird. Maybe it is something different or got lost in translation. I read that it is a projectile canon which uses electric propulsion system which was virtually noiseless. I guess designed as to not give away its location.

They had a wind canon too. I'm sure the Germans had many types up their sleeve. I doesn't seem that they know the purpose for the Bell.

Oh, I found stuff on the sound (shockwave) canon. If you could put it to music...one giant phonograph???

Must stop...off topic...remove hands from keyboard...


----------



## Joey Voltage

cagamp1 said:


> I doesn't seem that they know the purpose for the Bell.



Depends on who you ask, Either a air craft with some sort of advanced propulsion system, or some sort of time machine, but what ever it was it killed many scientists in its making.

Regardless, the development of the Nazi Propulsion systems in the 40's is the heart and foundation of our Space program. Wernher Von Braun became one of the chief rocket scientists at NASA after that whole operation paperclip thing.


----------



## cagamp1

Joey Voltage said:


> Depends on who you ask, Either a air craft with some sort of advanced propulsion system, or some sort of time machine, but what ever it was it killed many scientists in its making.
> 
> Regardless, the development of the Nazi Propulsion systems in the 40's is the heart and foundation of our Space program. Wernher Von Braun became one of the chief rocket scientists at NASA after that whole operation paperclip thing.


 
I read some of that. Strange stuff indeed.
You wanted the best...you got the best...the hottest rocket man on the planet...

And, he shielded everything. (keepin it on topic)


----------



## MajorNut1967

cagamp1 said:


> I read some of that. Strange stuff indeed.
> You wanted the best...you got the best...the hottest rocket man on the planet...
> 
> And, he shielded everything. (keepin it on topic)



I can see who the real science guys are here and I salute you!


----------



## TwinACStacks

MajorNut1967 said:


> Okay I'll build the resonance chambers!



 I wanna Push the Button.

 TWIN


----------



## MajorNut1967

TwinACStacks said:


> I wanna Push the Button.
> 
> TWIN



OK you do realize there are explosive chemicals involved! LOL


----------



## TwinACStacks

Just let me Push the God-damn Button.

[ame=http://www.youtube.com/watch?v=PyT4H11maeM]YouTube - Push the Goddamn Button[/ame]

 TWIN


----------



## Australian

I must admit I expected this thread to be more amplifier related, but it seems I've walked in to a cocktail party.


----------



## TwinACStacks

We only allow the finest types in here.

 TWIN


----------



## Adwex

Australian said:


> I must admit I expected this thread to be more amplifier related, but it seems I've walked in to a cocktail party.



Me too.

Guys, please save the unrelated banter for other threads.


----------



## TwinACStacks

TWIN


----------



## MajorNut1967

Australian said:


> I must admit I expected this thread to be more amplifier related, but it seems I've walked in to a cocktail party.



"Der Klang Kanone" is an massive sound amplifier it's just not driven with electricity and vacuum tubes as its power source, it's driven by hydrogen and oxygen in liquid form. "Push a god damn button!"


----------



## MajorNut1967

TwinACStacks said:


> We only allow the finest types in here.
> 
> TWIN



LOL Twin you are killing me today!


----------



## Joey Voltage

MajorNut1967 said:


> OK you do realize there are explosive chemicals involved! LOL



Oh C'mon, Just let him push the Goddamned button will ya?, he only has like what two good years left!? maybe?....

Just sit him in the Denny's booth... inner or outter doesn't matter because depends are on tight, give him an old Atari joystick you found at a goodwill, and, and tell him he is doing something important for humanity will ya!


----------



## thrawn86

Congrats on the Sticky, Lane. You're a good guy, and always willing to help out.

 from the Forum!

(PS: You guys can have your German technology.....I want a Death Star, Sun Crusher or Galaxy Gun instead.)


----------



## TwinACStacks

Joey Voltage said:


> Oh C'mon, Just let him push the Goddamned button will ya?, he only has like what two good years left!? maybe?....
> 
> Just sit him in the Denny's booth... inner or outter doesn't matter because depends are on tight, give him an old Atari joystick you found at a goodwill, and, and tell him he is doing something important for humanity will ya!



Snot-Nosed so and so....

 TWIN


----------



## MajorNut1967

Oh oh Daddy Adwex said we can't play on the thread no more! This must be one of those stuffy Tea & Crumpets thread. I'm off to where the pints flow freely as well as the thinking & discussion are not squelched.


----------



## thrawn86

MajorNut1967 said:


> Oh oh Daddy Adwex said we can't play on the thread no more! This must be one of those stuffy Tea & Crumpets thread. I'm off to where the pints flow freely as well as the thinking & discussion are not squelched.



In your case, 'thinking' isn't something you can do away with (as you don't think 97% of the time), and 'discussion' means 'argument' in your dictionary anyway. 

You silly fruit-booter.


----------



## TwinACStacks

Try the 6100 thread, There is no continuity or content there. It's great for rebels like Us.

 TWIN


----------



## Lane Sparber

Well, I'm preparing a blog about a DSL I just did a TON of work on. That should lead us back on topic, or maybe it will just lead somehow to a discussion of which wines go well with certain types of fish...



-Lane


----------



## TwinACStacks

Do Tell.... I've often wondered about a Good Cabernet Sauvignon. Along with Cap replacement on a DSL.

 TWIN


----------



## thrawn86

Thanks Lane. We knew you'd be bringing the sanity back.


----------



## Joey Voltage

Lane Sparber said:


> Well, I'm preparing a blog about a DSL I just did a TON of work on. That should lead us back on topic, or maybe it will just lead somehow to a discussion of which wines go well with certain types of fish...
> 
> 
> 
> -Lane



Well, Normally I would be all game for this information, being that I'm fond of fish of all sorts, and I'm a whino, but the last time I cooked it two months ago, it stunk up the whole house, and since it is winter, and I can't crack a window because it is so goddamned cold, and only one heater really works at my place. It still kinda smells like it. 

I'll tell you what!, you give me that wine list, and Blues 'n' Cues gives that dry rub recipe, I will trade you for my Arrabiatta gravy recipe. I'm also good at Indian, and some Thai, and can make a mean Chili..... Keeping the doors open


----------



## thrawn86

So, you can fix/build amps, but can't fix a stinkin' (no pun intended) heater? They've got maybe 4 wires and one heating element in them.


----------



## Lane Sparber

Joey Voltage said:


> Well, Normally I would be all game for this information, being that I'm fond of fish of all sorts, and I'm a whino, but the last time I cooked it two months ago, it stunk up the whole house, and since it is winter, and I can't crack a window because it is so goddamned cold, and only one heater really works at my place. It still kinda smells like it.
> 
> I'll tell you what!, you give me that wine list, and Blues 'n' Cues gives that dry rub recipe, I will trade you for my Arrabiatta gravy recipe. I'm also good at Indian, and some Thai, and can make a mean Chili..... Keeping the doors open



That Chili recipe sounds DAMNED good...and I am a sucker for a good bowl of Chili. Maybe we can work something out. 

I hope to have this new blog up by Friday afternoon, if I'm lucky.

-Lane


----------



## MajorNut1967

thrawn86 said:


> In your case, 'thinking' isn't something you can do away with (as you don't think 97% of the time), and 'discussion' means 'argument' in your dictionary anyway.
> 
> You silly fruit-booter.



Oh what did the lil' Nor-Cal tree hugger grow some testicular's, you wana run with the Big Dogs now? I think you better stay on the porch with the rest of the puppies. Boy you talk a good one like we've been talking long showers till the early morning hours. If you really kept track, you would see that I don't put much thought into the Wankers and I certain only argue with the Wankers regularly, but what you forgot to mention is the ones that don't get taunted are gents that respect themselves & others and who have genuine desire to listen and learn safely.

So my Nor-Cal bro I can hear your song just a play'n, "Kumbaya my Lord, Kumbaya!" Hey weren't you ones of those folks that were living in the trees at Berkley try to prevent The Man from cutting them down in the name of progress? Peace Brother and may Lord Krishna smile upon you!

What the bloddy hell is a, "Froot Booter" LMAO?


----------



## Joey Voltage

thrawn86 said:


> So, you can fix/build amps, but can't fix a stinkin' (no pun intended) heater? They've got maybe 4 wires and one heating element in them.



wires... priceless

You western people, and your electricity!

No sorry Thrawn, I'm talking about a nearly 100yr old cast Iron Radiator


----------



## thrawn86

Jus' messin' with you, Joey.

Hey Mango Kid, go look in a mirror, if you have one that Gilligan and his crew left you. _That's_ a Fruit Booter.

I don't hug trees. And I love animals............they taste great.


----------



## Alabama Thunderpussy

Thrawn loves animals until they get into his pot garden and start trampling his crop.


----------



## TwinACStacks

I think all you guys have been smoking herb.

 TWIN


----------



## thrawn86

Actually, I'm the one guy on here who doesn't.

But enough about fruit booting and pot gardens. Let's anxiously await Lane's blog. Thanx for being a good sport, Lane.


----------



## Lane Sparber

thrawn86 said:


> Actually, I'm the one guy on here who doesn't.
> 
> But enough about fruit booting and pot gardens. Let's anxiously await Lane's blog. Thanx for being a good sport, Lane.



Thanks again for the kind words.

+1 on the doesn't thing. I am completely clean...including alcohol, and, believe it or not, have made it to the ripe old age of almost 37 (next month!) without ever being drunk or high. I'm wacky enough without that stuff!

Back to topic, I reviewed my photos last night and all looks in order, so maybe Friday I can put it together as planned. 

-Lane


----------



## Australian

Thats highly commendable Lane. I dont drink, or take drugs either and really appreciate people setting a high standard.


----------



## Joey Voltage

thrawn86 said:


> Jus' messin' with you, Joey.
> 
> Hey Mango Kid, go look in a mirror, if you have one that Gilligan and his crew left you. _That's_ a Fruit Booter.
> 
> I don't hug trees. And I love animals............they taste great.



I'm not really sure on the regional connotations of a fruit booter, or fruit boots, but over here fruit boots are what we call roller blades, or roller bladers.


----------



## demonufo

Australian said:


> Thats highly commendable Lane. I dont drink, or take drugs either and really appreciate people setting a high standard.




I haven't done any of that stuff in years either. Don't miss it one bit.


----------



## Alabama Thunderpussy

thrawn86 said:


> Actually, I'm the one guy on here who doesn't.
> 
> But enough about fruit booting and pot gardens. Let's anxiously await Lane's blog. Thanx for being a good sport, Lane.




Pssh.. please. I know how you boys pay your billz up there in the Nor Cal mountains.


----------



## TwinACStacks

Alabama Thunderpussy said:


> Pssh.. please. I know how you boys pay your billz up there in the Nor Cal mountains.



They probably are in the Forest harvesting those funny Mushrooms...

 TWIN


----------



## thrawn86

Alabama Thunderpussy said:


> Pssh.. please. I know how you boys pay your billz up there in the Nor Cal mountains.



You know because you buy? Shame Shame! 

@Lane: Good for you my man. I do partake of the alcohol a little, but not to drunkeness. Like you, though, everyone thought for the longest time that I was a druggie or crack addict, simply because I do everything at top speed and am crazier than a loon when it comes to most things.


----------



## MajorNut1967

TwinACStacks said:


> I think all you guys have been smoking herb.
> 
> TWIN



Now who's Herb and why did we smoke him?


----------



## TwinACStacks

MajorNut1967 said:


> Now who's Herb and why did we smoke him?



'Cause he was steppin' on our turf, talkin' smack. We *HAD* to smoke him, Blood....

 TWIN


----------



## TwinACStacks

BTW: I survived the 60's. I'm as Clean as Lane is Now for at least 25 Years.

Although there may still be some residual effect left from the "Summer of Love" years....

 TWIN


----------



## MajorNut1967

TwinACStacks said:


> 'Cause he was steppin' on our turf, talkin' smack. We *HAD* to smoke him, Blood....
> 
> TWIN



Ok in the kings English?


----------



## Lane Sparber

*Repairing a DSL Part One: UP IN FLAMES!*

Hey all! For your entertainment (and _possible_ education), here’s the first installment of a blog about some repairs I did on my own new (and VERY used) DSL. Here’s the story, and I hope you enjoy it. Grab some popcorn! 

I’ve always been a huge Alkaline Trio fan. Since 2001 or so, their music has been a large part of my life. My Trio vinyl collection is almost embarrassing, actually. In mid-December of last year, whilst playing on e-Bay, I stumbled on an auction for Trio guitarist Matt Skiba’s own 1998 JCM 2000 DSL head. It was being sold by a friend of his old tech’s, and it even came with the custom made Anvil road case - still bearing all of the stencils and stickers Matt put on it. This head had been used on the first 3 Trio albums and had toured the world – including the far East. It's played every size venue imaginable, from arenas and stadiums to outdoor festivals to basement parties. The seller was asking just 500 bones (INCLUDING shipping) for the whole works! I couldn’t pass it up. It was advertised as “non-working,” which I didn’t worry about, but at the time I had no idea just how “non working” it really was! 

For reference, here’s a YouTube video of Matt playing this amp at the House of Blues in Anaheim in 2001. Notice the stickers and decals on the front of the head in the first few seconds of this vid – you’ll be seeing them again soon! The Marshall Logo is still attached at this point:

[ame=http://www.youtube.com/watch?v=UvCCSYhhDio&feature=related]YouTube - Alkaline trio misterchainsaw live[/ame]

…and here’s him using it again in 2002 (the vid is shaky, but the head is clearly visible to his right). Now, the logo is gone and the “Obey” sticker that is on there to this day has been put on:

[ame=http://www.youtube.com/watch?v=hY17x3Jmk6Q&playnext=1&list=PLA8B6A92702BE8D71]YouTube - Alkaline Trio - Radio[/ame]

So, I paid my money and eagerly awaited the arrival of this minor piece of punk history to arrive. Once the head arrived, it became readily apparent just how much I was up against. First, the foam in the road box had rotted and had attached itself to the head over almost all of it’s visible surface. It had also crumbled INTO the amp through the tube vents up top. Sigh. Well, off the road case went back to Anvil to get re-foamed. With that done, I decided to try a test. I removed all four power tubes and tried turning on the amp. To begin, I flipped the power switch and got power transformer hum. A good sign! Then, I flicked the standby on.

FOOM! 

I jumped back as flames shot out of the V8 tube socket. I quickly shut the amp off and took some time out to calm down.  Clearly it was time to begin the repair process.

I should point out at this juncture that I was NOT treating this as a standard repair – it was a restoration job. As this amp is a collectable piece that I wanted to keep just as Matt had it, I was NOT going to do ANY modification work of of any sort, although it was tempting. This included leaving the 220k grid swamper resistors in instead of swapping them out for the more appropriate 5.6ks, leaving C46 in the circuit as is, and finally, using the same brands of tubes that Matt used (some of which were not brands I’d normally use). I found that the amp still had it’s original Marshall branded Chinese preamp tubes. They were completely worn out, so I ordered low-noise Shugangs to replace them. The fried power tubes were JJEL34Ls (YES!), so I also ordered a matched quad of those. The only other maintenance I wanted to do was a FULL cap job – all 37 electrolytic caps or so.

Next, I cracked the amp open, and found the interior to be basically clean and unmodded. True to it’s era (early 1998), every board was an issue 1 with the exception of the tube board. The tube board an issue 3 and thus had the beefed up filtering array on the DC filament supply amongst other improvements. The only change was that a tech at some point had replaced C63 with a 1 watt metal film resistor. No biggie. However, there was rotten foam residue everywhere from the road case, which you can see as the black dust all over everything in these pics (sorry some of them are a bit blurry – I am NOT a photographer!):
















The following pic shows that C46 was intact on the V8 socket – alive and well and obviously not part of the flame problem:






Before moving on, I blew out the ENTIRE chassis with compressed air to get rid of that rotten foam residue. What a MESS!

Then, it was time to remove the tube board and get to the real work. There are two ways to approach work on the tube board. The SHORT method is to remove the 8 screws by the power tube sockets, then unscrew the 8 or so Phillips screws on the component side holding the board to the tube board tray, and then undo the 6 screws holding the tube tray to the chassis. If you then undo the molex connector to the bias board, you can remove the tube board tray completely and then leave the main board “suspended in space” by it’s connectors. This is fine if you’re doing relatively minor repairs such as replacing the plate load resistors, but seeing as how I needed to do intensive work on this board, I decided to fully remove it; both for ease of working on it and to save undo strain on the molex cables – I didn’t want to have to replace those! I then labeled each cable at the tube board end with my P-Touch labeler, because my handwriting is atrocious. Was it time consuming? YES, but that paid off later.

Once I got the tube board completely free of the amp, much to my chagrin I found THIS:






Someone had spilled something (Jack Daniels?? Coke??) onto this board, and it had clearly crystallized around that socket. When the B+ hit it, kaboom. This was NOT going to be fun. Again…sigh. First step, remove C46 and the V8 socket:






Here’s how I went about cleaning this mess: First, I soaked the entire area of the spill with 91% isopropyl alcohol and let it sit for a few minutes to try and soften the spilled matter. Then, I used my extremely fine metal polishing sandpapers starting with 6000 (yes, 6000) grit and got to work removing the gunk from the socket area. I was not concerned with the periphery as it wasn’t going to cause problems – I just wanted that socket area clean. Working slowly and constantly re-saturating the area with more alcohol to loosen the crud, I moved incrementally up to 12,000 grit sandpaper, by which point the board and contacts were clean. Actually, I was starting to remove the green dye from the board! Time to stop. Finally, I used an X-Acto #11 blade to scrape INTO the board between each solder pad affected to remove any trace of carbon arcing. Here’s what I wound up with:






Much cleaner, no?  Next I moved on to the tube socket using much the same processes, however this was a much more difficult job because it was a contoured 3 dimensional piece as opposed to a flat board, but eventually I prevailed (I don’t give up easily!). Would it have been easier to just replace the damned thing? YES! However, as I said above, I wanted to keep as many original parts as possible. Here's the cleaned socket:






I soldered it back onto the board and checked for continuity to each pin from the board to verify that no traces were compromised during any of the work, and it checked out just fine. Here is a matching angle shot to an above pic showing how relatively clean it was at this point in the process:






Finally, here are two bird’s eye views of the completed repair to that part of the amp:











This done, the amp was ready to begin the re-cap process, which I’ll cover in detail in my next installment.

Thanks for sticking with me so far, and I hope you’re enjoying the read!

-Lane


----------



## Stymie13

Great photos and description Lane! Thanks a lot for taking the time to post. I am really looking forward to the re-cap since I've only done my power filter caps.


----------



## Australian

Very interesting, and great pics to boot! 
I'm surprised how those tube holders sit on the circuit board like that. They dont look like they'd stand too much rough treatment while removing tubes.


----------



## Lane Sparber

Australian said:


> Very interesting, and great pics to boot!
> I'm surprised how those tube holders sit on the circuit board like that. They dont look like they'd stand too much rough treatment while removing tubes.



They're also screwed directly to the metal tray that the tube board sits in, so they do have SOME support. Still not an ideal situation by any stretch, tho.

-Lane


----------



## TwinACStacks

Very Nice Lane. Excellent job, just as I expected it would be. On My Issue 5 Tube board the traces actually ran along the outboard side of V8 where C46 was mounted to the Board with it's own set of Pads on the Traces. (1999)

 TWIN


----------



## TwinACStacks

MajorNut1967 said:


> Ok in the kings English?



He was in Our neighborhood Talking Shit so we had to kill him, Mate.

They don't teach Hoodspeak down in the S. Pacific?

 TWIN


----------



## MajorNut1967

Nice work Lane! Excellent pics & great dialogue, keep it up very in formative.


----------



## MajorNut1967

TwinACStacks said:


> He was in Our neighborhood Talking Shit so we had to kill him, Mate.
> 
> They don't teach Hoodspeak down in the S. Pacific?
> 
> TWIN



Oh I gotcha. Well the younger kids in New Zealand try to talk like that (they want to emulate the American kids), but in our house you speak Samoan, Tongan and or English properly or you’ll get knocked across the room.


----------



## chuckharmonjr

MajorNut1967 said:


> Ok in the kings English?



He walked into an area that he shouldnt have...and we excerised extreme sanction by shooting hin in the frontal lobe.


----------



## Joey Voltage

TwinACStacks said:


> He was in Our neighborhood Talking Shit so we had to kill him, Mate.
> 
> They don't teach Hoodspeak down in the S. Pacific?
> 
> TWIN



Yeah but keith, if you are going to pull out all the ghetto euphemisms you have to do it right, I mean c'mon I'm sure you have spent time in Hamtramck. 

It should read something like this: "mmmhmmm, them two mu'fuckas Tyrone an Herb, they out they goddamn mind, I done rolled up on that mu'fucka Herb cause he think he a badass mu'fucka from aroun the way, next time I smoke that mu'fucka.. don't make me no diffrence"

something like that with just a lot more "N" bombs


----------



## chuckharmonjr

but with the 'ah' suffix Joey...not the proper 'er'...lool


----------



## Adwex

Nice blog Lane. I didn't know there was such a thing as 8,000 grit sandpaper....let alone 12,000. I thought 800 was the finest anyone would ever need.


----------



## MajorNut1967

chuckharmonjr said:


> He walked into an area that he shouldnt have...and we excerised extreme sanction by shooting hin in the frontal lobe.



Roger that Mate!


----------



## diesect20022000

Australian said:


> Thats highly commendable Lane. I dont drink, or take drugs either and really appreciate people setting a high standard.


 same here. I have TRIED some before and HATED them and did drink socialy but, i'm done with all of it and happy i am. I never developed an addiction save cigarettes which i am quitting . I never found doping to be that appealing honestly. nothing againhst those who enjoy it i just have things that i feel are better for me to occupy my time with.


----------



## Lane Sparber

*Repairing a DSL Part Two: Electric Boogaloo*

Hello and welcome to the second installment of my DSL repair blog. In this section, I’ll share some tips and tricks that should help you re-cap your DSL quickly and effectively. 

I started with one of JCMJMP on this forum’s HT cap kits. While I am more than capable of spec’ing all of my own caps, I wanted to support a fellow forum member who’d already done the work for me. I was VERY satisfied with the caps he sent me, and highly recommend one of his kits. The rest of the caps I spec’d myself from Mouser using the usual criteria of good ESL/ESR ratings and also using the largest, best rated caps I could that would still fit the board in terms of layout and lead spacing. You do-it-yourselfers out there will find links to the caps I spec’d in the appendix after this post for your convenience. I did NOT spec the caps from JCMJMPs kit though, for reasons that I hope are obvious.

Moving on, since the tube board was already out of the amp, I started there. You’ll notice if you try to re-cap your own DSLs that all of the HT caps are hot glued to the board to stabilize them. This obviously needs to be removed to change out the caps. There are a couple of methods you can use to get that old glue out of there. Sometimes, I use my trusty old #11 X-Acto blade to pry up a corner and go from there. Other times, if the glue is accessible enough, I simply grab it with needle-nosed pliers and gently pull it off of the board. In this case, I used BOTH methods, and to my pleasant surprise I found that once I was able to get a grip on the glue, each section pretty much came off intact and I was able to remove all traces of the old glue. While gluing the caps in is not completely necessary, I do highly recommend it and do so on all of the amps I work on. I replaced all of the HT caps first. Once they were all in, I moved on to all of the smaller electrolytic capacitors. I suggest you take your time with this job and DO NOT RUSH. You MUST observe proper polarity with these caps (except for the two bi-polar caps on the tube board – with these two orientation obviously doesn’t matter). Marshall has made it easy for you by marking the orientation of each cap with a “+” sign where the positive lead is supposed to go. Make sure each cap is as completely flush to the board as you can get it before soldering it in place. Once each cap was in, I tested the continuity of each lead’s trace to make sure I hadn’t damaged anything. You don’t HAVE to do this step, but it IS an extra measure of insurance. Finally, when all caps were in, I heated up the glue gun and fastened all of the HT caps to the board with a conservative dose of glue. Keep it as neat as you can, as hot glue likes to run and gets everywhere! Try not to use any more than you have to. Also, as each cap was removed, I placed it in a tiny Ziploc baggie with it’s component number and value written on it for safekeeping. YES, I am a bit anal retentive (insert rude comments here).

Here are some before/after contrast pics of the tube board when it was finished and ready to go back into the amp. Note the hot glue at the base of all of the HT caps in each picture.

The main HT caps before:






…and after:






The other end of the board showing the old 10uf cap array:






…and the new ones:






Here’s the other side showing the old DC filament filter caps:






…and the new ones I spec’d:






Here’s the board re-mounted in it’s tray with the bias board’s Molex reconnected. The bottom:






…and the top:






Then, when that was all done, I used the six mounting screws to re-install the whole assembly back onto the main chassis, like so:






This is a shot of the main interior before reconnecting all the cables. It’s a spaghetti MESS in there, and you can clearly see my P-Touch labels on some of the cables.






REALLY take your time re-connecting the cables and make sure you’ve got them all situated correctly…and then check again. The margin for error on this step is quite large, so be advised and be thorough and it should turn out fine.

I was doing this repair one board at a time so that if there was a problem, I could at least isolate it to that board. With that in mind, and since I was hoping I was DONE with the tube board (and as it turns out I was), it was time to form those new caps on the Variac. I brought the voltage up slowly over the course of an hour or so, checking the B+ voltage, heater voltages, and bias voltage at each incremental raise of the Variac just to make sure everything was progressing smoothly. Here’s the amp attached to the Variac:






Once the amp was up to 120vac, I tested it to make sure all functions worked. To my extreme satisfaction, everything worked…and more importantly…NO SMOKE OR FLAMES! WHEW!!

On the DSL, because the two 100uf caps and the two 330uf caps in the HT supply are wired in series, they DO have bleeder resistors to stabilize the voltage across each cap. This means that if you unplug the amp and leave the standby on, over the course of a few minutes the caps WILL drain themselves, but you should still be safe and ALWAYS check this with a meter before proceeding.

I was now ready for the next step, which was going to be recapping the rear board (the one with the output jacks on it). This board was already loose because you have to remove it and cut the cable ties along the back of the amp to remove the main tube board. I had left all of the connectors intact on this board and just pushed it out of the way while removing the tube board. Now I could easily flip this board over and work directly on it.

While on this step, it’s worth mentioning that I had idly wondered before getting the amp which impedance jack Matt used, and I got two major clues to this from the amp itself. First and most obviously, Matt’s old tech had replaced the red plastic nuts on both of the 4/8 ohm jacks with black ones, leaving the 16 ohm jack naturally highlighted. When I flipped this board over, I noticed that all of the solder pads on the 16 ohm jack were cracked and not making good contact anymore. Clearly, this wear was from speaker cables being constantly inserted into and subsequently removed from this jack. Clue number two! Now I had my answer. So, in addition to replacing the caps on this board, I strengthened ALL of the jack connections here with liberal doses of solder to try and make them more “bullet proof.” These beefed up joints are clearly visible to the bottom right of the photo below, which shows that board flipped over inside the amp for solder work:






To re-iterate, for this and every other board I recapped, I left the Molex connectors ON for the work, and to minimize stress on them, I de-soldered all of the caps at once and replaced them all in one shot. This way I only had to flip the board over a few times. With the new caps in place, I fired the amp up again and tested all functions. All was good, so it was time to recap the pot board after re-fastening and wire-tying the rear board back in place.

Here’s the faceplate with the pot board removed and lying inside the amp. The new wire ties I installed along the back of the amp are clearly visible here:






…and here’s the pot board flipped over to work on. There are only about 4 electrolytic caps on this board, so it was fairly quick and easy. I should note that in the “D1” position on this issue 1 board, there’s actually an axial electrolytic cap installed there. I don’t know if it’s in later revisions, but it’s worth pointing out.






With those caps replaced, I tested the amp again. All systems were a go, so I completed the re-cap with the reverb board. This was the easiest to work on because you just need to remove three small Phillips screws and you can pull the board right out. Here it is out of the amp where I worked on it:






Once again, I fired it up and everything worked! Here’s shot of the entire inside of the amp fully reassembled and ready for biasing:






It looks like a PC, doesn’t it? 

My loaded plate voltage at 120vac from the wall was dead-on at 460vdc exactly, so in order to bias the amp to 65% dissipation on each side, my calculation was as follows:

25w/460vdc*.65+5ma for screen current (the bias test pins measure cathode current, so you DO need to add that 5ma!), which worked out to about 40ma per tube (rounded), and thus 80ma per side. So, after letting the amp warm up for 15 minutes or so, that’s where I set each side’s bias pot.

Constant touring and the rigors of the road had destroyed the output transducer on the original Accusonics reverb tank, and I discovered when I tried to get a replacement that Accusonics had been bought out by Belton (a Korean company) and their tanks were no longer available, so I went with a MOD reverb tank built to the same specs (4BB3C1D). I actually like it better in some ways, because the inductors are wired directly to the RCA jacks as opposed to using the push-on connectors that Accusonics tanks did that could, and sometimes DID fail. Here’s a side-by-side shot of the old and new tanks:

Top:






Bottom:






Here’s a close-up of the output transducer on the old tank. Notice that “GONE” is written in green on the tank flange next to it. _Someone_ knew it was dead! Also note that the stanchion that was supposed to support the spring board during any undue jostling has been knocked COMPLETELY out of the tank, leaving just a hole in the reverb tank’s chassis. This amp has seen a LOT of action, I tells ya!






I will conclude in the next post. Happy reading!


----------



## Lane Sparber

*Repairing a DSL Part 3: Attack of the DSL*

Thanks for staying with me so far...if you have!

Now, all that was left was to re-assemble the amp and enjoy! Here’s everything installed and ready to go:






This is the back of the completed head. Note the single red nut on the 16 ohm jack that I wrote about above:






Here’s the front of the amp:






Finally, here’s the old cap morgue:






This amp sounds KILLER, and the old sound of Alkaline Trio IS in this amp. It was an involved repair, but totally worth it, and I hope you all were entertained by this account of how I got it back up and running, and can maybe take something away from my recounting of the experience.

Cheers!

-Lane


----------



## Lane Sparber

*Repairing a DSL Appendix: Caps and Sandpaper*

Here’s a list of the caps I used in this amp. While your quantities may vary depending on board revision number, the actual caps themselves are the same. As stated in my last post, the HT caps are NOT spe’d here, as I don’t want to step on JCMJMP's toes. I suggest you take your amp apart, count your own totals, and then use these links to order your new caps. All capacitors are radial unless noted:

22uf/25v Axial Capacitor (I needed 1):

TVX1E220MAD Nichicon Aluminum Electrolytic Capacitors - Leaded

10uf/100v (I needed 3):

ECA-2AHG100I Panasonic Electronic Components Aluminum Electrolytic Capacitors - Leaded

1000uf/16v (I needed 2):

EEU-FC1C102B Panasonic Electronic Components Aluminum Electrolytic Capacitors - Leaded

470uf/35v (I needed 3):

SK471M035ST Mallory Aluminum Electrolytic Capacitors - Leaded

3300uf/10v NOTE: the following caps have thicker leads than the stock caps. They WILL fit, you just need to remove every molecule of old solder from the holes (I needed 4):

EEU-FC1A332 Panasonic Electronic Components Aluminum Electrolytic Capacitors - Leaded

4.7uf/63v (I needed 1):

EEU-EB1J4R7 Panasonic Electronic Components Aluminum Electrolytic Capacitors - Leaded

1uf/100v (I needed 1):

ECA-2AM010B Panasonic Electronic Components Aluminum Electrolytic Capacitors - Leaded

22uf/50v (I needed 1):

EEU-FR1H220 Panasonic Electronic Components Aluminum Electrolytic Capacitors - Leaded

47uf/63v (I needed 8):

UPM1J470MPD1TD Nichicon Aluminum Electrolytic Capacitors - Leaded

22uf/50v BI-POLAR caps (I needed 2):

UES1H220MPM Nichicon Aluminum Electrolytic Capacitors - Leaded

Also, just because Adwex asked about them, here’s where I got my ultra fine grit sandpapers:

STEWMAC.COM : Micro-Mesh Finishing Abrasives Kit

There you have it…all of the caps (minus the HT) that you need to get your amp back in tip-top shape. Enjoy, and happy restoring!

-Lane


----------



## Michael1987xl

Excellent blog, Lane! Great detail, helpful instruction and a clear indication of the kind of time, patience, attention to detail and level of talent it takes to do it. Further proof that while there may be 1,000 ways to do this type of restoration, 999 of them are wrong and only 1 of them is right. I'd also add that you may have set the bar for this type of post so high, a lot of us are going to fall over backwards looking at it it. Really well done.

One question, though: any chance you can identify the really interesting piece I spied off to the far left of these two photos?


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## Lane Sparber

Yeah...I found it in the trash!!  Just kidding! I knew you'd spot that. 

-Lane


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## Michael1987xl

Oh, come now, you edited that! I have to admit, though, it's funnier this way!


----------



## Lane Sparber

Michael1987xl said:


> Oh, come now, you edited that! I have to admit, though, it's funnier this way!



Sometimes it takes me a couple of tries to be "funny" at this hour! Cut an old boy some slack!! 

-Lane


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## jcmjmp

Nice work, Lane! 
Those speaker jacks are touchy. Its real important to ensure that the nut are always tight on those or you'll end up with bad solder connections. Never had any issues with mine though. If I do, I'll replace them with chassis mounted jacks and run wires to the impedance selector.


----------



## TwinACStacks

Joey Voltage said:


> Yeah but keith, if you are going to pull out all the ghetto euphemisms you have to do it right, I mean c'mon I'm sure you have spent time in Hamtramck.
> 
> It should read something like this: "mmmhmmm, them two mu'fuckas Tyrone an Herb, they out they goddamn mind, I done rolled up on that mu'fucka Herb cause he think he a badass mu'fucka from aroun the way, next time I smoke that mu'fucka.. don't make me no diffrence"
> 
> something like that with just a lot more "N" bombs



However in Hamtramck You are more likely to get assaulted with a Paczki, Pierogi or one of Mrs. Schmenki's Cabbage Rolls....

 TWIN


----------



## thetragichero

let me know if you want an original accutronics tank from a 1998 dsl100
i sure don't use it


----------



## Lane Sparber

thetragichero said:


> let me know if you want an original accutronics tank from a 1998 dsl100
> i sure don't use it



No need to do that to your amp! I have the MOD, and that's all it needs for now. I do SERIOUSLY appreciate the offer, my friend. 

-Lane


----------



## thrawn86

How much does the MOD tank run? I've belayed replacing mine (which is bunk) and it's also a 4BB3C1D.

Great Blog, Lane. And very good photography.


----------



## Lane Sparber

thrawn86 said:


> How much does the MOD tank run? I've belayed replacing mine (which is bunk) and it's also a 4BB3C1D.
> 
> Great Blog, Lane. And very good photography.



Thanks, Thrawn! Much appreciated.

The tanks are $18.00 here:

More Info for item P-RMOD-4BB3C1D

Happy reverbing! 

-Lane


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## thrawn86

Wow, super cheap! Now I have no excuse. I dig the black paint too.


----------



## Lane Sparber

thrawn86 said:


> Wow, super cheap! Now I have no excuse. I dig the black paint too.



They sound pretty good, too IMHO. Glad to be of service!

-Lane


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## thrawn86

Mine took a dive a few years after I had the amp. 

When I built the new headbox for it, I made it short....there will be just enough room to fit it under the tubes! But I have been missing my onboard Reverb for some time.


----------



## MajorNut1967

thrawn86 said:


> Mine took a dive a few years after I had the amp.
> 
> When I built the new headbox for it, I made it short....there will be just enough room to fit it under the tubes! But I have been missing my onboard Reverb for some time.



What! You lost your reverb! Say it isn't so. I heard there is a lot of lost reverberation in the Grand Canyon, may be you can find it there?


----------



## thrawn86

Yeah, Mango lover, we have Reverb here in the States. Flat landers don't have that.


----------



## Lane Sparber

So...my work schedule is about to drive me underground for a bit, but I will resurface soon. I can still answer questions, but time for involved projects like blogs will be hard to find. Until then, ponder this:

What topics should I consider next? Is there any repair that you'd like to see me try to cover? Please...keep the requests serious and on the level, and I'll do my best to try and put something together.

Thoughts? Comments? Rants?

Let me know!

-Lane


----------



## Michael1987xl

Lane Sparber said:


> Is there any repair that you'd like to see me try to cover?



I'm curious to see what you'd do with a H.H. Scott LK-48 Stereo amplifier from 1964 or so with a wicked hum in it if such an amazing piece were to get dropped off at your door....


----------



## Lane Sparber

Michael1987xl said:


> I'm curious to see what you'd do with a H.H. Scott LK-48 Stereo amplifier from 1964 or so with a wicked hum in it if such an amazing piece were to get dropped off at your door....



-Replace all electrolytic caps using a combination of direct FP style replacements and discreet under-chassis axial capacitors.

-Replace failing selenium rectifier that feeds the 12vdc preamp tube heater string and EL84 bias voltage with a new 10 amp 400v silicon bridge rectifier (I over-rated it because it is a key factor in the bias string, so if it fails, bye-bye power tubes and possibly OTs!).

-Replace 18 ohm 1 watt CC carbon comp resistor after the diode bridge above with new 5 watt 33 ohm resistor to compensate for the newer, more efficient rectifier bridge installed above. This step maintained the -16 to -18vdc on the grids of the EL84s and the 11 to 13vdc on the preamp DC heater strings as per factory specs

-Correct several lead dress issues

-Replace all 12AX7s and EL84s with new

-Replace all of the crappy paper coupling caps with polyester film caps (orange drops) for improved consistency and reliability (this is the only remaining step).

Next question?? 

-Lane


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## Michael1987xl

Well, sure, of course, that's exactly what I would expect you to do.

You get an "A".


----------



## Lane Sparber

Michael1987xl said:


> You get an "A".



Is that redeemable for a handsome set of luggage? Or A NEW CAR?!? 

-Lane


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## peterichardz

*Hi Lane, How about power scaleing for my '77 JMP 50 watt 2204?*


----------



## Michael1987xl

Lane Sparber said:


> Is that redeemable for a handsome set of luggage? Or A NEW CAR?!?
> 
> -Lane



Oh no no. Being a fan of Vintage Wheel of Fortune, you get the pair of 3' tall ceramic Dalmatians and another free vowel.


----------



## Lane Sparber

peterichardz said:


> *Hi Lane, How about power scaleing for my '77 JMP 50 watt 2204?*



Good suggestion...I will look into that. I confess to never having implemented that specific mod before, so maybe we could learn the best way to install this together! 

-Lane


----------



## peterichardz

Lane Sparber said:


> Good suggestion...I will look into that. I confess to never having implemented that specific mod before, so maybe we could learn together!
> 
> -Lane



*If it was designed well, I think it would be a very useful mod a lot of guys playing clubs would want.

I'm not a tech, but am taking a theory coarse and will be assembling a kit for practical experience soon.*


----------



## Lane Sparber

peterichardz said:


> *If it was designed well, I think it would be a very useful mod a lot of guys playing clubs would want.
> 
> I'm not a tech, but am taking a theory coarse and will be assembling a kit for practical experience soon.*



Good for you! FYI, here's a link to a pretty cool power scaling kit, just for reference. Check it!

Power Scaling Kits & More - - Super Flexible Power Scaling Kit for Fixed-Bias Amp

...and more info on their stuff:

http://www.londonpower.com/catalog/about_our_ps_kits.php

I have heard a good thing or two about them.

-Lane


----------



## peterichardz

Lane Sparber said:


> Good for you! FYI, here's a link to a pretty cool power scaling kit, just for reference. Check it!
> 
> Power Scaling Kits & More - - Super Flexible Power Scaling Kit for Fixed-Bias Amp
> 
> ...and more info on their stuff:
> 
> http://www.londonpower.com/catalog/about_our_ps_kits.php
> 
> I have heard a good thing or two about them.
> 
> -Lane



*Thanks Lane. I've heard that Marshall may have started there also?*


----------



## Lane Sparber

peterichardz said:


> *Thanks Lane. I've heard that Marshall may have started there also?*



Marshall stared with THIS company? If that's what you mean, then no. I'm a little confused by what you meant here. 

-Lane


----------



## peterichardz

Lane Sparber said:


> Marshall stared with THIS company? If that's what you mean, then no. I'm a little confused by what you meant here.
> 
> -Lane



*I read some place on the net that the technology for Marshalls power scaling started at London Power.
I may be wrong though.*


----------



## Lane Sparber

peterichardz said:


> *I read some place on the net that the technology for Marshalls power scaling started at London Power.
> I may be wrong though.*



I'm not sure. Maybe Santiago will chime in if he reads this. Anyway, that kit might be the way to go if you're a do-it-yourself type! If you'd like me to do it, I will certainly make a blog out of the install process once my schedule frees up.

-Lane


----------



## peterichardz

*That's cool. When I get the funds together, Ill get with you and put this together.*


----------



## Lane Sparber

peterichardz said:


> *That's cool. When I get the funds together, Ill get with you and put this together.*



Sweet. Might be a bit before I'm free again anyway!

Cheers!

-Lane


----------



## Joey Voltage

I wouldn't use the O'Connor one, it is overly complicated for what it is. you can design a suitable one yourself, as all it really is for the most part is dual source followers controlling the B+ Voltage, and Bias voltage simultaneously....or If you are not well versed in Solid state, check out Dana Halls VVR. It's much easier. I'm doing something similar to Blues Rockers 1959 reissue, and it takes up a lot less space.


----------



## Lane Sparber

Joey Voltage said:


> I wouldn't use the O'Connor one, it is overly complicated for what it is. you can design a suitable one yourself, as all it really is for the most part is dual source followers controlling the B+ Voltage, and Bias voltage simultaneously....or If you are not well versed in Solid state, check out Dana Halls VVR. It's much easier. I'm doing something similar to Blues Rockers 1959 reissue, and it takes up a lot less space.



Copy that! Thanks, Joey!

Peter: Here you go:

http://www.hallamplification.com/main.html#2,2

-Lane


----------



## peterichardz

*WOW! I've e-mailed the Hall brothers to check that out. It's REALLY small.
Thanks Lane & Joey!*


----------



## MajorNut1967

Okay this to Peter & Lane, "why would a person own a 50 watt Marshall and then want to power scale it?" If it's too loud for you get an amp that suits your needs? Marshall amps are loud and it's part of the character.


----------



## CKCinMass

Lane Sparber said:


> Copy that! Thanks, Joey!
> 
> Peter: Here you go:
> 
> http://www.hallamplification.com/main.html#2,2
> 
> -Lane



Has anyone tried one of these out?


----------



## Lane Sparber

MajorNut1967 said:


> Okay this to Peter & Lane, "why would a person own a 50 watt Marshall and then want to power scale it?" If it's too loud for you get an amp that suits your needs? Marshall amps are loud and it's part of the character.



I assure you, Major, that this would be a GREAT feature for playing some of the smaller clubs in the Villiage if you love the sound of your amp and don't want to buy a new one.

-Lane


----------



## MajorNut1967

Lane Sparber said:


> I assure you, Major, that this would be a GREAT feature for playing some of the smaller clubs in the Villiage if you love the sound of your amp and don't want to buy a new one.
> 
> -Lane



again why own amplifier is too loud for what you're doing? and if you like the sound of your amplifier without the power scaling installed, do you really think this can sound the same way when you turn it down with the power scaler? because I'll tell you up front it doesn't sound the same, because I've done it!and while it did reduce the volume great deal according to what you need, it never sounds like the original amplifier.

It kind of goes back to my old adage, "why do you buy a 1970 SS 454 big block Chevelle to drive around your grandmas backyard?"


----------



## Lane Sparber

MajorNut1967 said:


> again why own amplifier is too loud for what you're doing? and if you like the sound of your amplifier without the power scaling installed, do you really think this can sound the same way when you turn it down with the power scaler? because I'll tell you up front it doesn't sound the same, because I've done it!and while it did reduce the volume great deal according to what you need, it never sounds like the original amplifier.



Point taken. I know folks who love their power scaling and those who don't. As this mod (like most) has good and bad attributes, it is up to the individual to decide for him or herself based on their own research and experience if they want the mod or not. This is why Joey and myself each guided Peter to different websites to learn as much as he could prior to installation...should he even choose to go that route. 

As to WHY Peter bought this amp or whether or not it's the right amp for him, I'll let him explain that one for you! 

-Lane


----------



## thrawn86

Because most of us are spoiled by the Marshall sound.......however impractical for small clubs, venues, etc.......and won't resort to using a Line 6.


----------



## MajorNut1967

thrawn86 said:


> Because most of us are spoiled by the Marshall sound.......however impractical for small clubs, venues, etc.......and won't resort to using a Line 6.



Bunch peace & quiet lovers! Damn the torpedoes full speed head! lets make everybody's ears bleed and if they don't like it tell them to go the flock out.


----------



## solarburn

Oh Shizzy mon! The Maj says don't nut a Marshall! Its got balls. Use them!LOL


----------



## Joey Voltage

MajorNut1967 said:


> again why own amplifier is too loud for what you're doing? and if you like the sound of your amplifier without the power scaling installed, do you really think this can sound the same way when you turn it down with the power scaler?



I'm not all too sure how many would expect it to sound the same anyway with scaling or an attenuator to be honest. Even if it did/does in the frequency domain, a lot of how we percieve the tone of any amp really depends on how we respond to changes in SPL, not that the amp itself is sounding any better.

Some people may want it just to add some versatility. You can get some pretty gnarly almost Variac'd sounds out of scaling the whole amp, and if you design it yourself, it costs next to nothing.


----------



## MajorNut1967

Joey Voltage said:


> Some people may want it just to add some versatility. You can get some pretty gnarly almost Variac'd sounds out of scaling the whole amp, and if you design it yourself, it costs next to nothing.



Again why own a 2204 power scaled, Like you said if you want the variac sound and or can build your own Power Scaler do that. Or go buy a Line 6. LOL


----------



## Joey Voltage

MajorNut1967 said:


> Or go buy a Line 6. LOL



Thats a lot more money than a VVR, unless you rob Carnada.


----------



## Adwex

MajorNut1967 said:


> Bunch peace & quiet lovers! Damn the torpedoes full speed head! lets make everybody's ears bleed and if they don't like it tell them to go the flock out.



That attitude won't work for a gigging band.


----------



## Lane Sparber

Adwex said:


> That attitude won't work for a gigging band.



That's been my experience as well. It also doesn't really work in your drummer's basement, either...although I CAN get the Jubilee pretty loud in there. The DSL, however, FORGET IT! 

-Lane


----------



## thrawn86

92% of this thread has nothing to do with amps, mods, blogs, Lane, or Marshalls. Sorry Lane. I still like what you post.


----------



## Lane Sparber

thrawn86 said:


> 92% of this thread has nothing to do with amps, mods, blogs, Lane, or Marshalls. Sorry Lane. I still like what you post.



Thanks, man! I still try to stay on topic, but I can't control what happens here. I thought we were getting back on track with some power scaling mods, but apparently, I was wrong.



-Lane


----------



## thrawn86

That's what I was getting at. You're on point and everyone else is 'Lemming' it up. Rock on bro!


----------



## MajorNut1967

I guess if you consider gigging in a basement real gigging ok. And Adwex you are saying if you play rock music loud you don't get gigs? Since when did it become how quiet you played got you gigs and not your talent? And when did Rock Music get so quiet in your worlds? It kind of sounds like you guys could daisy chain your earbuds & Ipods and just get down! LOL


----------



## Lane Sparber

MajorNut1967 said:


> I guess if you consider gigging in a basement real gigging ok. And Adwex you are saying if you play rock music loud you don't get gigs? Since when did it become how quiet you played got you gigs and not your talent? And when did Rock Music get so quiet in your worlds?



Erm...Major...we PRACTICE in the drummer's basement! A DSL 100 cranked in there could, quite literally, take out a wall!! 

-Lane


----------



## MajorNut1967

Lane Sparber said:


> Erm...Major...we PRACTICE in the drummer's basement! A DSL 100 cranked in there could, quite literally, take out a wall!!
> 
> -Lane



Um so your DSL 100 could take out a wall? wow So what do you think my Major would do to the wall?


----------



## Lane Sparber

MajorNut1967 said:


> Um so your DSL 100 could take out a wall? wow So what do you think my Major would do to the wall?








-Lane


----------



## thrawn86

Run too much juice through it and fry your coconut press. Maybe your Weed Dryer, if you left it in long enough.


----------



## BluesRocker

Lane Sparber said:


> -Lane


----------



## Adwex

MajorNut1967 said:


> I guess if you consider gigging in a basement real gigging ok. And Adwex you are saying if you play rock music loud you don't get gigs? Since when did it become how quiet you played got you gigs and not your talent? And when did Rock Music get so quiet in your worlds? It kind of sounds like you guys could daisy chain your earbuds & Ipods and just get down! LOL



I'm saying that if the soundguy or the owner tells you to turn it down, and you don't, you may not play there again. I've been told this several times. A paying gig is like a job, you do what the boss tells you to do if you want to keep the job.


----------



## MajorNut1967

Lane Sparber said:


> -Lane



LOL

Well mine won't do that it's just a guitar amp, but if your's will knock down walls, "I'm scared of you" as my daughter says.


----------



## MajorNut1967

thrawn86 said:


> Run too much juice through it and fry your coconut press. Maybe your Weed Dryer, if you left it in long enough.



Okay what does that mean? Lane you speak Thrawns lingo HELP?


----------



## thetragichero

i've always played cranked, but then again i no longer live in a city like lane (i think the old lady next door must be deaf since she's never called the cops)
never had a problem cranking my dsl or 350watt bass amp at gigs, but we're more in the dive bar circuit than playing in snobby rock clubs


----------



## thrawn86

MajorNut1967 said:


> Okay what does that mean? Lane you speak Thrawns lingo HELP?



It means 'The walls fell down go boom. My appliances are destroyed from the current, including the one I use to process my NZ Mary Jane.'


----------



## thrawn86

Ok Ok, I'm sorry. I'm not posting here again until Lane posts something of real value. I've done enough damage!


----------



## peterichardz

MajorNut1967 said:


> I guess if you consider gigging in a basement real gigging ok. And Adwex you are saying if you play rock music loud you don't get gigs? Since when did it become how quiet you played got you gigs and not your talent? And when did Rock Music get so quiet in your worlds? It kind of sounds like you guys could daisy chain your earbuds & Ipods and just get down! LOL



*Ok Major, Heres the deal. I DO play about 100 dates a year with my 2204 screaming for mercy with the pre on 10 and the master on 5-6 in a LOUD Old School Rock band.

But I just recently started playing the same music in several sports bars during the week nites ( that pay VERY well ) that need the level lower due to other buisnesses being open during the show. I just thought I'd ask around about power scaling as I love the tone I have, and there IS no other small amp that sounds like my "77 JMP 2204.

I've made a very good living over the last 40 plus years with my cranked Marshalls, but in todays economy you have to take the jobs where they are.*


----------



## SigurdTheGreat

peterichardz said:


> *Ok Major, Heres the deal. I DO play about 100 dates a year with my 2204 screaming for mercy with the pre on 10 and the master on 5-6 in a LOUD Old School Rock band.
> 
> But I just recently started playing the same music in several sports bars during the week nites ( that pay VERY well ) that need the level lower due to other buisnesses being open during the show. I just thought I'd ask around about power scaling as I love the tone I have, and there IS no other small amp that sounds like my "77 JMP 2204.
> 
> I've made a very good living over the last 40 plus years with my cranked Marshalls, but in todays economy you have to take the jobs where they are.*



How about getting a THD HotPlate instead of modding your beloved amp?


----------



## peterichardz

SigurdTheGreat said:


> How about getting a THD HotPlate instead of modding your beloved amp?



*I have 2 '77 JMP 2204's. One I bought new and one I bought off craigslist that had been modded and didn't work which is the one I will install the power scaling in. The mod I'm looking at would not be very invasive as it will install in one output jack. And in my experience attenuators DO change the tone.*


----------



## MajorNut1967

peterichardz said:


> *Ok Major, Heres the deal. I DO play about 100 dates a year with my 2204 screaming for mercy with the pre on 10 and the master on 5-6 in a LOUD Old School Rock band.
> 
> But I just recently started playing the same music in several sports bars during the week nites ( that pay VERY well ) that need the level lower due to other buisnesses being open during the show. I just thought I'd ask around about power scaling as I love the tone I have, and there IS no other small amp that sounds like my "77 JMP 2204.
> 
> I've made a very good living over the last 40 plus years with my cranked Marshalls, but in todays economy you have to take the jobs where they are.*



I got ya Mate! A true Player of Music. "Hat's off to you Bro!"


----------



## j2112c

Lane, quick question....

I have an LP and a Hamer Standard, I decided I would go up in string guage to 11's on both... hmm.. well I expected the LP to have a lower string tension with a shorter scale neck... what I find is the LP is really restrictive with bending now due to increased string tension, but the Hamer has taken them and 'one tone plus' bends are still no problem.

Is this right..? Have I got this the right way around..?
what other factors are there ot string tension.

I could keep 11's on the Hamer, but not the LP it is horrid now... I guess I am a 10's player!


----------



## Lane Sparber

j2112c said:


> Lane, quick question....
> 
> I have an LP and a Hamer Standard, I decided I would go up in string guage to 11's on both... hmm.. well I expected the LP to have a lower string tension with a shorter scale neck... what I find is the LP is really restrictive with bending now due to increased string tension, but the Hamer has taken them and 'one tone plus' bends are still no problem.
> 
> Is this right..? Have I got this the right way around..?
> what other factors are there ot string tension.
> 
> I could keep 11's on the Hamer, but not the LP it is horrid now... I guess I am a 10's player!



Hey, John!

String tension is a function of mass, scale length, and pitch. In general, with all things being equal, longer scale lengths exhibit _higher_ string tension than shorter scale lengths, so in that you are correct.

That being said, each guitar reacts differently to changes in string gauge. This is partially due to the overall design of and type of wood used in the instrument in question. Some can retain a lot of their "feel" (for lack of a better word) with strings of different gauges, and some really accentuate the differences. If I had to hazard a guess, I'd say that since the Hamer probably already had higher tension due to it's longer scale, the jump wasn't as noticeable to you. For the shorter scale Les Paul, it was a much greater jump. As I said, this is JUST A GUESS, as it's hard to say for sure without the guitars in front of me. Did you re-do the setup? Especially the truss rod adjustments?

Opinions differ on this, and I'm sure that if so inclined, the other techs will chime in with their opinions, rants or flames.

Here's a GREAT article written on this issue if you really want to delve into the science behind this phenomenon:

String Tension

-Lane


----------



## j2112c

Lane Sparber said:


> Hey, John!
> 
> String tension is a function of mass, scale length, and pitch. In general, with all things being equal, longer scale lengths exhibit _higher_ string tension than shorter scale lengths, so in that you are correct.
> 
> That being said, each guitar reacts differently to changes in string gauge. This is partially due to the overall design of and type of wood used in the instrument in question. Some can retain a lot of their "feel" (for lack of a better word) with strings of different gauges, and some really accentuate the differences. If I had to hazard a guess, I'd say that since the Hamer probably already had higher tension due to it's longer scale, the jump wasn't as noticeable to you. For the shorter scale Les Paul, it was a much greater jump. As I said, this is JUST A GUESS, as it's hard to say for sure without the guitars in front of me.
> 
> Opinions differ on this, and I'm sure that if so inclined, the other techs will chime in with their opinions, rants or flames.
> 
> Here's a GREAT article written on this issue if you really want to delve into the science behind this phenomenon:
> 
> String Tension
> 
> -Lane



Thanks Lane, it has been a while, I guess they are keeping you busy in your corner here.

Thanks for the reply, that might well be the case that he perception is just that the jump was more noticable. I actually thought if I was going to have a problem it would be the Hamer, but it did not turn out that way... I will try them until this set of strings are out and then decide what I am going to do with the gauges... stick or twist..

I will check out the link later tonight, thanks mate.


----------



## Lane Sparber

j2112c said:


> Thanks Lane, it has been a while, I guess they are keeping you busy in your corner here.
> 
> Thanks for the reply, that might well be the case that he perception is just that the jump was more noticable. I actually thoought if I was going to have a problem it would be the Hamer, but it did not turn out that way... I will try them until this set of strings are out and then decide what I am going to do with the gauges... stick or twist..
> 
> I will check out the link later tonight, thanks mate.



No problem! Stop by any time. We are (almost) always open! 

-Lane


----------



## Adwex

Don't forget to consider the length of string "behind" the bridge and nut...these sections of the string will play a role in perceived change in string "tension" while bending.


----------



## Lane Sparber

Adwex said:


> Don't forget to consider the length of string "behind" the bridge and nut...these sections of the string will play a role in perceived change in string "tension" while bending.



Ya know, Adwex...that's an interesting point. Both of JC's guitars have average length headstocks and stop bar/Tune-O-Matic bridges without locking systems (which would nullify the headstock and behind the bridge sections of string). I believe his Hamer headstock is 6 on a side and, obviously, the Les Paul headstock has a 3 and 3 arrangement. These differences might be a factor in the perceived tension differences as well.

EDIT: Rather than taking your word for it, John, I did some research.  According to what I've found, BOTH guitars you mention have the same scale length (24 3/4"). This is a game changer, because if they are set up in a similar manner with the exact same action and the exact same neck adjustments, the tension should at least be _similar_, although never exactly the same due to differences in intonation settings, imperfect string diameters, different extra string lengths behind the nut and bridge, etc. If they DO have the exact same setups, then I'd attribute the drastic differences in feel to the factors Adwex and I mentioned above, with the possible addition of different nut and saddle friction being another contributing factor.

This is a tricky one, because, like "tone," "feel" is a HIGHLY subjective term, and what feels like higher tension to one player does not necessarily feel the same way to another. In conclusion, I'd agree with your own assessment: keep 10s on the Paul and 11s on the Hamer, and you'll get the best of both worlds...to your own hands, at least! 

-Lane


----------



## MajorNut1967

Adwex said:


> Don't forget to consider the length of string "behind" the bridge and nut...these sections of the string will play a role in perceived change in string "tension" while bending.



What? explain you theory on this please!


----------



## j2112c

Lane Sparber said:


> Ya know, Adwex...that's an interesting point. Both of JC's guitars have average length headstocks and stop bar/Tune-O-Matic bridges without locking systems (which would nullify the headstock and behind the bridge sections of string). I believe his Hamer headstock is 6 on a side and, obviously, the Les Paul headstock has a 3 and 3 arrangement. These differences might be a factor in the perceived tension differences as well.
> 
> EDIT: Rather than taking your word for it, John, I did some research.  According to what I've found, BOTH guitars you mention have the same scale length (24 3/4"). This is a game changer, because if they are set up in a similar manner with the exact same action and the exact same neck adjustments, the tension should at least be _similar_, although never exactly the same due to differences in intonation settings, imperfect string diameters, different extra string lengths behind the nut and bridge, etc. If they DO have the exact same setups, then I'd attribute the drastic differences in feel to the factors Adwex and I mentioned above, with the possible addition of different nut and saddle friction being another contributing factor.
> 
> This is a tricky one, because, like "tone," "feel" is a HIGHLY subjective term, and what feels like higher tension to one player does not necessarily feel the same way to another. In conclusion, I'd agree with your own assessment: keep 10s on the Paul and 11s on the Hamer, and you'll get the best of both worlds...to your own hands, at least!
> 
> -Lane





Ah thanks for the edited info Lane, sorry I thought one was longer than the other. Yes the distances behind the nut are different and the nut of course too it is a strange one as though the access is not the best at the heal of an LP so reducing mechanical advantage for a bend, I still find in other areas it is more taught.. very odd. 

My mate is coming around this weekend I will get him to play them both and see what he thinks just in case it is me being odd.. ...not the first time As it is physically difficult to bend the LP with 11's... I will probably go back down a gauge there... thanks for taking the time to check it out for me mate, appreciated.


----------



## Lane Sparber

MajorNut1967 said:


> What? explain you theory on this please!



I believe it does make a difference, Major...although primarily only when bending strings. 

Let's say we want to bend a string 1/2 step up, and for our purposes here we assume that there's no extra length before the nut or behind the bridge (like in a Floyd Rose style locking system). That extra stretch now has to come from ONLY the "speaking" length of the string, whereas if there's extra length provided by the headstock and tailpiece, the string now has both of those "reservoirs" to cull from during the bend, which COULD be said to contribute to a "looser" feel. Check out this article. The luthier who penned it explains the concept pretty well.

Lutherie Myth/Science: Human Perception of String Tension and Compliance in Stringed Musical Instruments

I submit/propose this solely for the purposes of discussion and debate...I do NOT want to turn this into a flame war! 

-Lane


----------



## MajorNut1967

Lane Sparber said:


> I believe it does make a difference, Major...although primarily only when bending strings.
> 
> Let's say we want to bend a string 1/2 step up, and for our purposes here we assume that there's no extra length before the nut or behind the bridge (like in a Floyd Rose style locking system). That extra stretch now has to come from ONLY the "speaking" length of the string, whereas if there's extra length provided by the headstock and tailpiece, the string now has both of those "reservoirs" to cull from during the bend, which COULD be said to contribute to a "looser" feel. Check out this article. The luthier who penned it explains the concept pretty well.
> 
> 
> 
> I submit/propose this solely for the purposes of discussion and debate...I do NOT want to turn this into a flame war!
> 
> -Lane



well if you can sit here and tell me that from the standpoint of physics, okay!


----------



## TwinACStacks

What I CAN tell you is that the well proportioned Young Lady in J2112c's signature, Even IF she had Wings, could not possibly Fly. It's simply a weight VS lift thing. Much like a Bumble Bee.

There's some Physics for Y'all.....


 TWIN


----------



## Lane Sparber

TwinACStacks said:


> What I CAN tell you is that the well proportioned Young Lady in J2112c's signature, Even IF she had Wings, could not possibly Fly. It's simply a weight VS lift thing. Much like a Bumble Bee.
> 
> There's some Physics for Y'all.....
> 
> 
> TWIN



What about an African or European Swallow? Could either of THEM fly with those...um..."wings?"

-Lane


----------



## Lane Sparber

*Marshall 6550 to EL34 Conversion*

Hello, all!

As I am going to be quite busy for a little while, I figured I'd do a little "mini-blog" here to fill the gap until I get more time, and as usual I hope you enjoy it! As with any of the mods I discuss in this thread, you MUST stay safe and practice proper safety procedures when working on these amps, so once again, READ MY SIG and understand it before attempting any work on a tube guitar amp!

One of the most often asked questions here on the forum seems to be "How do I convert my 6550 equipped Marshall to use EL34s?" The inverse question is also frequently asked here as well. To that end, I intend to demonstrate in the simplest terms possible how to do this mod.

There are basically only 3 resistors to change: a bias range resistor and the grid leak resistors on the power tubes. 6550s require more negative bias voltage to operate safely in these amps, so the circuit was altered to allow for this. As to why the grid leak resistors were changed, 6550s have higher grid leakage current than EL34s, and so too high of a value of resistor here (such as the 220k resistors used for EL34s) can add positive bias to the tube, in turn causing more plate current to be drawn. This happens cyclically and before you know it, you're red-plating, and that's a BAD thing.

First, let's look at the schematic. I have drawn red arrows to the resistors we need to change here, and even though the scan is not the best, you can see that the grid leak resistors are labeled "220K" with a parenthetical note that says "150K for U.S.A." and the bias range resistor is labeled "27K" with a parenthetical note that says "15K for U.S.A." These are the three resistors we're going to change.






Here's a 1980 2203 that came to my shop equipped with 6550s. I have circled the three resistors (corresponding to the three resistors we just looked at on the schematic) that we need to change:






What we're going to do is swap those two 1/2 watt 150K resistors (color code brown/green/yellow/gold) for 220K resistors (color code red/red/yellow/gold) for our EL34s we want to install. These resistors are easy to find; they're almost always connected to the green and orange wires (1 each) going to the 5.6K grid swamping resistors soldered to the power tube sockets. Once those are replaced, then we will change that bias range resistor from 1/2 watt 15K (color code brown/green/orange/gold) to a 1/2 watt 27K (color code red/violet/orange/gold) in order to allow less negative voltage through. This in turn will allow us to get the EL34s biased at the proper dissipation.

I use 1% metal film resistors for most of my amp work, although almost any type would work. I DO shy away from carbon comp resistors due to reliability and noise issues, although this is admittedly subjective. If you want to do the mod using the same parts I did, you can find the 220K 1/2 watt resistors here:

273-220K-RC Xicon Metal Film Resistors - Through Hole

The 27K resistor I used can be found here:

273-27K-RC Xicon Metal Film Resistors - Through Hole

Here's the finished product ready for biasing. It's also worthy of note in this photo that I have replaced the two bias filter caps as well. 






Some folks say that you also have to move the purple feedback wire around on the output impedance selector when you perform this mod. You do NOT need to do this. You can if you wish...it all depends on the amount of negative feedback you want for your amp. I CAN say that I have seen 6550 equipped Marshalls in my shop with the purple wire on the 4 ohm tap, and some had it on the 8 ohm tap, so even Marhsall got all "willy-nilly (to use the Major's term)" with this area of the circuit when they were assembling the amps. I humbly suggest trying the wire on each tap and seeing which sound you like best.

So, there you have it. Three resistors and a bias job and the amp is ready to rock it's new power tubes! By way of additional info, if you want to go from EL34s to 6550s, simply reverse this mod as I have laid it out. If you want to use KT88s, it's basically the same mod, just use 100K grid leak resistors instead. The 15K bias range resistor should work for the KT88s as well. If you need, you can go to a 10K bias range resistor for KT88s, but as a rule I've found that not to be necessary.

Good luck and happy modding! 

EDIT: Also, JCMJMP supplies this info on going from 5581/6L6 types to EL34s...should you wish to do so. THANKS, JCM!

http://www.lydian.ca/Marshall_Misc_files/5881_EL34conversion.pdf

-Lane


----------



## TwinACStacks

Lane Sparber said:


> What about an African or European Swallow? Could either of THEM fly with those...um..."wings?"
> 
> -Lane



Well, they can carry coconuts....

 TWIN


----------



## MajorNut1967

TwinACStacks said:


> Well, they can carry coconuts....
> 
> TWIN



I like coconuts, a lot! and I can carry 20 at a time.

Another thing you folks in the west teach your children not to play with fire, where I come from we encourage it!

[ame="http://www.youtube.com/watch?v=9ONgF5LniEM&feature=related"]http://www.youtube.com/watch?v=9ONgF5LniEM&feature=related[/ame]


----------



## thrawn86

MajorNut1967 said:


> I like coconuts, a lot! and I can carry 20 at a time.
> 
> Another thing you folks in the west teach your children not to play with fire, where I come from we encourage it!
> 
> YouTube - Polynesian Cultural Center Dance Fire PCC Canon ZR500 demo



The PCC is very cool. My wife and I went when on our honeymoon in Oahu. I tried to do the freakin' Tahitian hula. It was like trying to play guitar left handed for me.


----------



## duffhuff

Lane Sparber said:


> What about an African or European Swallow? Could either of THEM fly with those...um..."wings?"
> 
> -Lane


Monty Python ref??

"It's not a question of where he grips it! It's a simple question of weight ratios!"


----------



## MajorNut1967

thrawn86 said:


> The PCC is very cool. My wife and I went when on our honeymoon in Oahu. I tried to do the freakin' Tahitian hula. It was like trying to play guitar left handed for me.



You know Thrawn I think we're going to adopt you! Oh and it's not the "Tahitian Hula" it's either Aparima, Otea or Ahuroa! LOL


----------



## thrawn86

MajorNut1967 said:


> You know Thrawn I think we're going to adopt you! Oh and it's not the "Tahitian Hula" it's either Aparima, Otea or Ahuroa! LOL



Sorry. I can't remember precisely which one, other than they made me do it in front of like 150 people that were too cowardly to do it. I know it had more to do with rocking the heels than it did with moving the hips, and trying to mimic the lady opposite from me was impossible........kinda like the old saying about 'walking and chewing gum at the same time'. I can walk and chew gum at the same time, but the Hula? Nope. Couldn't stop laughing.

Y'know. Whiteys. We got no rythym.


----------



## Lane Sparber

Okay...after several members have contacted me about this, I'm now gonna have to publicly say it...let's stay on topic, gentlemen...or take it to another thread, pleez! 

-Lane


----------



## jcmjmp

6L6/5881 <-> EL34 conversion:
http://www.lydian.ca/Marshall_Misc_files/5881_EL34conversion.pdf


----------



## Lane Sparber

Thanks, JCM! That fits right in with my last blog.

I'm going to add this link in with it! 

-Lane


----------



## MajorNut1967

thrawn86 said:


> They kept picking me for all the stuff because I wore my yellow shirt.
> For your amusement, Major:



You know that's my sister you are dancing with! Oh sorry I posted before I saw Lane's Stay on track thing!


----------



## thrawn86

Sorry Lane.


----------



## SigurdTheGreat

Hey Lane, great article! You do have the skill to strip things to bare essentials and leave the crap out – ever thought about teaching amp overhaul workshops or something?

Another conversion thing that came into mind that you could do an article about is the Silverface-era hum balance to bias pot conversion. As the prices on the '60s stuff skyrocket, people buy more and more '70s Silverface stuff, and need to get them working with CP tubes, so the conversion thing becomes more than acute. And you sure can explain that one as well with ease!


----------



## Lane Sparber

SigurdTheGreat said:


> Hey Lane, great article! You do have the skill to strip things to bare essentials and leave the crap out – ever thought about teaching amp overhaul workshops or something?
> 
> NAH! I'm too boring to hold anyone's attention that long! I'd put 'em to sleep!
> 
> Another conversion thing that came into mind that you could do an article about is the Silverface-era hum balance to bias pot conversion. As the prices on the '60s stuff skyrocket, people buy more and more '70s Silverface stuff, and need to get them working with CP tubes, so the conversion thing becomes more than acute. And you sure can explain that one as well with ease!



Answer to the first question above in blue.

As to the second suggestion, that's a GREAT idea! I will do a blog on this as soon as the next Fender that needs the "bias balance to true bias control conversion" comes into my shop! Any volunteers? 

-Lane


----------



## Michael1987xl

Lane Sparber said:


> As to the second suggestion, that's a GREAT idea! I will do a blog on this as soon as the next Fender that needs the "bias balance to true bias control conversion" comes into my shop! Any volunteers?



I'm guessin' we should have had a camera handy?


----------



## Lane Sparber

Michael1987xl said:


> I'm guessin' we should have had a camera handy?


Probably...but to be honest, I already can't remember what I did to that Bassman! Getting old SUCKS (37 tomorrow ).

-Lane


----------



## Michael1987xl

You think you're gettin' old because you can't remember what you did to that Bassman? Big deal; I can't remember being 37, although there are photographs which indicate that I actually did it.


----------



## MajorNut1967

Lane Sparber said:


> Probably...but to be honest, I already can't remember what I did to that Bassman! Getting old SUCKS (37 tomorrow ).
> 
> -Lane





Michael1987xl said:


> You think you're gettin' old because you can't remember what you did to that Bassman? Big deal; I can't remember being 37, although there are photographs which indicate that I actually did it.



Boy you think that's bad I can't remember,,, "wait what were we talking about?"


----------



## TwinACStacks

Lane Sparber said:


> Probably...but to be honest, I already can't remember what I did to that Bassman! Getting old SUCKS (37 tomorrow ).
> 
> -Lane



Happy B-Day, (much) Younger Bro....

 TWIN


----------



## CKCinMass

Happy Birthday Lane!!


----------



## Alabama Thunderpussy

For your birthday, I think we should start a new sticky thread:

Lane's Bathroom - One Tech's Log.

Tone is in the TP.


----------



## Adwex

Happy Birthday Lane!


----------



## Buggs.Crosby

Happy Birthday Lane ........37 and old.....ha ha!!


----------



## peterichardz

Adwex said:


> Happy Birthday Lane!





*Yeah Man!!!!​*


----------



## Lane Sparber

Thanks for all of the well wishes, guys! Much appreciated, and it brightened my day considerably! 

To that end, I just HAD to post this pic of the custom made sign my wife got me for my birthday! It's now on my shop door. The invitation is open to all (please excuse the blurry pic):






Best. Wife. EVER!!!!

-Lane


----------



## Adwex

Buggs.Crosby said:


> Happy Birthday Lane ........37 and old.....ha ha!!



Take it from me, 37 ain't old.


----------



## MajorNut1967

Adwex said:


> Take it from me, 37 ain't old.



37 ain't nuttin you still got 10 years of serious pole vaulting left! LOL


----------



## diesect20022000

happy birf day Lane!


----------



## All4Tone

Wow, that is one cool sign. Happy belated and congratulations on a great wife. Jeez all that & only 37, you got it all, dude!

I must be quite the old fart on here at 52 (b'day in a few weeks… btw, it STILL aint too loud - ever!!!)


----------



## Adwex

All4Tone said:


> Wow, that is one cool sign. Happy belated and congratulations on a great wife. Jeez all that & only 37, you got it all, dude!
> 
> I must be quite the old fart on here at 52 (b'day in a few weeks… btw, it STILL aint too loud - ever!!!)



It is an extremely cool sign, display it proudly, Lane.

As far as being the old fart around here, I'm not far behind you, I just turned 48. At this age, if it ain't too loud, that probably means you didn't crank it enough when you were younger. Hundreds of concerts and rock clubs, and my car stereo did it for me, not just the Marshall.


----------



## TwinACStacks

MajorNut1967 said:


> 37 ain't nuttin you still got 10 years of serious pole vaulting left! LOL



Seriously. Are we talking about actual Pole Vaulting or is this a Metaphor for something bawdy?

I'm not up to speed on N.Z. humour....

 TWIN


----------



## All4Tone

Adwex said:


> It is an extremely cool sign, display it proudly, Lane.
> 
> As far as being the old fart around here, I'm not far behind you, I just turned 48. At this age, if it ain't too loud, that probably means you didn't crank it enough when you were younger. Hundreds of concerts and rock clubs, and my car stereo did it for me, not just the Marshall.




Well, to be honest, I can remember a few times when I was playing sort of beside my amp, so it was hitting me more on one side than the other & at the tend of those nights, I had what I often referred to "rubber ear", where your ear feels like it's just a piece of rubber on the side of your head, 'cause it doesn't hear anything...

Seriously though, these days, I don't mind the occasional blast from a stack, but I need my hearing to be intact, as I use my ears to make money, so they have to keep working.

When I work in the studio, I keep levels reasonable and vary them often. Doing a mix with hearing fatigue is a waste of time.

It's the old moth to flame scenario, musicians love it loud, but if they lose their hearing, they lose one of the most important things to them...


----------



## MajorNut1967

TwinACStacks said:


> Seriously. Are we talking about actual Pole Vaulting or is this a Metaphor for something bawdy?
> 
> I'm not up to speed on N.Z. humour....
> 
> TWIN



LOL yes it was somewhat of a metaphor, I guess the American equivalent is jumping off your headboard onto your wife while her ankles are tied behind her ears.


----------



## thetragichero

ouch that sounds dangerous!


----------



## TwinACStacks

MajorNut1967 said:


> LOL yes it was somewhat of a metaphor, I guess the American equivalent is jumping off your headboard onto your wife while her ankles are tied behind her ears.




The Judges Responses: 8.4 - 9.7 - 9.2 - 9.5 - 8.1 - 9.0


There seems to be some disagreement with the Soviet judges concerning the Dis-Mount.....


 TWIN


----------



## MajorNut1967

twinacstacks said:


> the judges responses: 8.4 - 9.7 - 9.2 - 9.5 - 8.1 - 9.0
> 
> 
> there seems to be some disagreement with the soviet judges concerning the dis-mount.....
> 
> 
> Twin



rofl


----------



## TwinACStacks

Major, I'm no Olympian, but I was brilliant this morning.

I even Stuck the Landing.


 TWIN


----------



## Lane Sparber

Awright...the birthday stuff was a great and welcome diversion, but once again let's get back on track with some tech stuff, gentlemen! 

-Lane


----------



## TwinACStacks

Lane, You got any Idea how TECHNICALLY perfect that landing Was?


 TWIN


----------



## MajorNut1967

TwinACStacks said:


> Lane, You got any Idea how TECHNICALLY perfect that landing Was?
> 
> 
> TWIN


----------



## MajorNut1967

Lane Sparber said:


> Awright...the birthday stuff was a great and welcome diversion, but once again let's get back on track with some tech stuff, gentlemen!
> 
> -Lane



Hey you go take a nap old man!


----------



## Lane Sparber

I give up!



-Lane


----------



## MajorNut1967

Lane Sparber said:


> I give up!
> 
> 
> 
> -Lane



Like I said, "Go take a nap!, you need it"


----------



## Lane Sparber

MajorNut1967 said:


> Like I said, "Go take a nap!, you need it"



Wait a minnit! Aren't you one of the members who PM'd me asking me to keep this thread to tech talk and not let it "run away?" I find this ironic! 

Also, you are correct...a nap might just be forthcoming so I can ditch this fever. 

-Lane


----------



## TwinACStacks

Sorry Lane. I'm okay now. I'm just like a Shark when it smells blood, I go into a Feeding frenzy....

 TWIN


----------



## CKCinMass

I was really looking forward to some info on power scaling mods that were mentioned until the train went directly off the tracks........


----------



## Lane Sparber

CKCinMass said:


> I was really looking forward to some info on power scaling mods that were mentioned until the train went directly off the tracks........



Well, in terms of me installing these mods in an actual amp and making a blog about it, that ball is in Peter's court at this point.  However, to check out some kits for yourself, I think you'll find posts #173 and #181 on this thread particularly useful. Being as how you've successfully built your own amp from scratch at this point, I can't see you having any problems installing these simple kits...and if you do, as always you have my number! 

-Lane


----------



## CKCinMass

Lane Sparber said:


> Well, in terms of me installing these mods in an actual amp and making a blog about it, that ball is in Peter's court at this point.  However, to check out some kits for yourself, I think you'll find posts #173 and #181 on this thread particularly useful. Being as how you've successfully built your own amp from scratch at this point, I can't see you having any problems installing these simple kits...and if you do, as always you have my number!
> 
> -Lane



Thanks Lane. I did look at those two units and am suprised at the price difference and overall appearance of the two. The Hall Amplification unit looks like it would be a piece of cake to install. Might be worth the $50 just to give it a whirl.


----------



## peterichardz

Lane Sparber said:


> Well, in terms of me installing these mods in an actual amp and making a blog about it, that ball is in Peter's court at this point.  However, to check out some kits for yourself, I think you'll find posts #173 and #181 on this thread particularly useful. Being as how you've successfully built your own amp from scratch at this point, I can't see you having any problems installing these simple kits...and if you do, as always you have my number!
> 
> -Lane



*Hi Lane and others.

I have purchased the VVR kit. It seems to be a very easy install, but I have not had the time as I've been playing alot. I will document the install and chat with Lane about posting it when complete. Again here is where to find it;*
http://www.hallamplification.com/main.html#2,2


----------



## Razzle

TwinACStacks said:


>


I'm rolling over here.


----------



## eddyrox

*Re: Repairing a DSL Appendix: Caps and Sandpaper*



Lane Sparber said:


> Here’s a list of the caps I used in this amp. While your quantities may vary depending on board revision number, the actual caps themselves are the same. As stated in my last post, the HT caps are NOT spe’d here, as I don’t want to step on JCMJMP's toes. I suggest you take your amp apart, count your own totals, and then use these links to order your new caps. All capacitors are radial unless noted:
> 
> 22uf/25v Axial Capacitor (I needed 1):
> 
> TVX1E220MAD Nichicon Aluminum Electrolytic Capacitors - Leaded
> 
> 10uf/100v (I needed 3):
> 
> ECA-2AHG100I Panasonic Electronic Components Aluminum Electrolytic Capacitors - Leaded
> 
> 1000uf/16v (I needed 2):
> 
> EEU-FC1C102B Panasonic Electronic Components Aluminum Electrolytic Capacitors - Leaded
> 
> 470uf/35v (I needed 3):
> 
> SK471M035ST Mallory Aluminum Electrolytic Capacitors - Leaded
> 
> 3300uf/10v NOTE: the following caps have thicker leads than the stock caps. They WILL fit, you just need to remove every molecule of old solder from the holes (I needed 4):
> 
> EEU-FC1A332 Panasonic Electronic Components Aluminum Electrolytic Capacitors - Leaded
> 
> 4.7uf/63v (I needed 1):
> 
> EEU-EB1J4R7 Panasonic Electronic Components Aluminum Electrolytic Capacitors - Leaded
> 
> 1uf/100v (I needed 1):
> 
> ECA-2AM010B Panasonic Electronic Components Aluminum Electrolytic Capacitors - Leaded
> 
> 22uf/50v (I needed 1):
> 
> EEU-FR1H220 Panasonic Electronic Components Aluminum Electrolytic Capacitors - Leaded
> 
> 47uf/63v (I needed 8):
> 
> UPM1J470MPD1TD Nichicon Aluminum Electrolytic Capacitors - Leaded
> 
> 22uf/50v BI-POLAR caps (I needed 2):
> 
> UES1H220MPM Nichicon Aluminum Electrolytic Capacitors - Leaded
> 
> Also, just because Adwex asked about them, here’s where I got my ultra fine grit sandpapers:
> 
> STEWMAC.COM : Micro-Mesh Finishing Abrasives Kit
> 
> There you have it…all of the caps (minus the HT) that you need to get your amp back in tip-top shape. Enjoy, and happy restoring!
> 
> -Lane


Lane, an insane blog and well worth reading (I will be reading this many times again, just to try and understand all of the information you've thoughtfully and thoroughly documented. WOW!
Thank you for taking the time.
Regards,
Mike


----------



## Lane Sparber

*Re: Repairing a DSL Appendix: Caps and Sandpaper*



eddyrox said:


> Lane, an insane blog and well worth reading (I will be reading this many times again, just to try and understand all of the information you've thoughtfully and thoroughly documented. WOW! Thank you for taking the time. Regards, Mike



Thanks, man! I am just glad that you enjoyed it. 

-Lane


----------



## Michael1987xl

Just a little something to add to Lane's thread. First. a little personal history to explain why I'm so jazzed about what eventually took place here:

Back in his youth, my dad had been a working jazz musician throughout high school, college and med school (as a way of putting himself through school). As a member of the local musician's union back in the late 1940's/early 1950's he had gotten to play with a lot of the greats. In fact, throughout his life and my childhood, he maintained friendships with most of these guys and everyone from name players to session guys were regular guests at our home. Just by way of example, Joe Morello who played drums for Dave Brubeck and past away just a few weeks ago was a regular at the house. Having been in these bands and hanging around with these guys as much as he did right up until his own passing 13 years ago, my dad knew what this music was supposed to sound like not just up close and personal, but in its recorded form as well. 

As a result, back in mid-1960's, my dad became something of an audiophile and subsequently had a real effect on how I grew to "hear" music, as well. A good friend of his was quite the electronics tinkerer himself and had built himself a H.H. Scott kit stereo amplifier which my dad had absolutely fallen in love with and he decided to get one of his own. Sometime in '64, he acquired a 24 watt, all tube (of course), Scott LK-48 integrated stereo amp which his buddy assembled for him and he used it pretty regularly for a few years; included in this set-up was a Scott tube FM Tuner (either a 110 or a 310, can't remember for sure), a turntable I can't recall, a Viking reel-to-reel deck and a pair of AR 2aX speakers. For the time, this was just about as cutting-edge as you could get in the home market, accordingly this was "His Stereo" set up in his little listening area and young hands at the controls were absolutely _verboten_, but I spent countless hours listening to just about anything from big bands to modern jazz and even modern rock with him. That was a real special time for me.

It was an amazing rig, but around '67 or so Scott released the LK-72 series integrated stereo amplifiers, which pumped out (for the time) a bone crushing 48 watts and I guess "he just had to have it". Almost immediately, the LK-72 was purchased, once again assembled by his buddy and replaced the LK-48; at this point an Acoustic Research (AR) turntable was added to the rig as well since it played not only 33 rpm disks, but 78's, too (the previous unremarkable one one being given to one of his other friends). A few years later (early 70's) my dad was spending more of his free time not just listening to his music but playing the drums again, as golf was just not his thing. He set up the old LK-48 down in the basement where the drum kit was, added another Scott tuner (pretty sure it was a 310 by this point), a Gerard turntable, and some speakers (I can't recall) which were blown and repaired regularly as played along on his Tempo kit (I've mentioned this in other threads) with his favorite records. As some of the years passed, this set up got more and more use by me and my brother and I became quite attached to it. 

In the late 70's I was going off to college and knew I'd need a stereo or I'd lose my mind. By that point, solid state was all the rage, to the point that that was about all you could get and even with my dad's offer of helping me pay for something "budget" (the money I was making playing in my band and working in a record store for the summers didn't really garner much cash), I was coming up short trying to find anything that had the warmth we had both very much grown accustomed to from those old Scott rigs, so we struck a deal; I'd buy a turntable, some amp 'suitable' to leave home for my younger siblings, my dad would score me a set of speakers and let me take the LK-48 off to school. With what cash I had, I hit Tech Hi-Fi (you old dudes remember that, don't lie!) scored a Technics SL-23 turntable, some solid state thingamabob for the basement, my dad grabbed me a pair of floor model KLH Research X speakers, handed off one of the Scott FM Tuners and I was off to school, armed with some excellent high fidelity. Back then, Infinity speakers, TEAC decks, Kenwood/Fisher/Pioneer/Fill-In-The-Blank-Here solid state rigs were all the rage, but they left me flat; I didn't have the watts to blast against those guys, but I was (and still am) willing to trade the quality of the sound for all that high-fallutin'-in-your-face sterile sound those guys had going. 

That LK-48 rig served me not only through college, but all through law school, as well. The only hiccup it developed was an occasional "hum", that quite by accident, I discovered went away if I pressed against the front panel. Knowing even less-than-the-nothing I know about fixings amps now, I decided that the way to remedy this situation was to use a piece of uber-sticky surgical tape to pull the front panel back to the chassis; genius, I know, but it worked and remained in place for a number of years. When I returned home and my dad wanted to set that rig up again in our dining room, I was immediately put on the spot to answer the "What the Hell is _THIS_?" about the tape strip, especially once he pulled it off and it's sticky remnant remained behind so beautifully on the chassis. Needless to say, this was what I like to call "an issue". 

As the years went by and my dad got older, the Scott amps developed some problems and he brought them to various people for repair, but they were never quite right again, he got tired of trying to find someone to fix them correctly and they were eventually packed away and replaced by a pretty good solid state system in the early 90's or so. Fast forward to 1998, my dad passed away, his equipment remained untouched and mostly forgotten about, or so I thought. A few years ago, having gotten "the bug" again, I decided to go through the stuff and set some of it up in my home only to discover that my mother had grown tired of having it all wrapped up in packing paper in the back of her laundry room and had taken it all to the local recycling center; both amps, both tuners, the walnut cases, the turntable, reel-to-reel deck, the whole f-ing smash. This was, of course, "an issue" between us and continues to be to this day; the less said about it the better, frankly. In any event, I immediately fired through my dad's old papers to find any info on what he'd purchased (he was a real stickler for keeping his records around) and while my mother had disposed of a lot of it, I was able to find the operating manual and build sheet for the LK-72 and the actual 11"x17" schematic for my old LK-48. Figuring this was the best I'd ever do, I had to be satisfied with a these items for a number of years to fill that part of the void of my memory of my dad. Yeah, it sucked, but what can ya do?

Fast forward a few more years and I'm still perusing e-bay pretty regularly to see what this stuff goes for these days, making myself increasing sick to my stomach in the process, and I see a local guy who's got an LK-48 for sale. 






Pretty cool, I'm thinking, same case and model as I had; neat-_o_. It's then that I spy_ this_:






Yep, look on the top of the chassis just just behind the front panel and you'll see the tell-tale tape mark that I'd gotten my ass ripped about almost 30 years ago. My dad and I didn't have too many tense moments between us, so I remembered it clearly. Anyway, I'm thinking it's just a coincidence until I see _this_:






Immediately, I dig out the papers I grabbed from my dad's files; the hand-written serial number for the LK-48 on the schematic is a dead-on _match_. It's about this time I start to experience shortness of breath and get some really good chest pain to go with it. I rifle through the rest of the guy's auctions to see if there's anything else that I'd recognize, but no luck. Now began the tortuous 6 day wait for the end of the auction, during which other guys keep bidding the price up and up and up. Undeterred, I stand my ground waiting patiently to snipe the amp at the last few seconds; f-ed up or not, I'm getting this thing and that's all there is to it, after all, I know great amp tech.

6 days later, for a Prince's ransom, BTW, to the Victor went the spoils....and that would be _ME_. 

I immediately drive to guys house to buy the thing and get the back story from him about how he acquired from another local guy a few years back for about what I paid for it, never did much with it, but "had it gone through a couple of times by his tech and that it sounded OK". I race home with it, hook up some speakers and..........welcome to Hummmm City, nestled in the County of Oscillating Whistles, State of Buzz-O-La. 

Shit.

Enter the young, talented and infinitely patient Lane Sparber, upon whose doorstep I unceremoniously dump this mess:











To Lane's credit, he did not curse me nor stab me in the eye with his soldering iron, all of which are perfectly viable, acceptable and commonly exercised options in New York, btw. I attribute this to the fact that all of this occurred in the middle of the December Holiday Season and, to a greater degree, that children and other witnesses were present at the time. In any event, the soldering iron was pointed towards the door and clearly marked the path of my expected exit which directive I followed immediately.

Over the course of the next few months, all of which I have been reliably assured were tortuous, Lane did his magic and I was eventually the grateful recipient of this:





























































In all honestly, this shows about 1/3 (if that) of the work Lane did so meticulously to this ole box o'tubes. To have him explain it (since I lack both the vocabulary and the knowledge) here's what happened: 


> The laundry list for this repair was quite large...full electrolytic re-cap, replace selenium rectifier with modern silicon diode bridge and adjust the resistors for the filament/bias supply accordingly, replace all paper caps with poly Sprague "orange drops," replace all plate load resistors with 1% metal film resistors, and a full re-tube. I also converted the last gain stage/phase inverter tubes from the rare and expensive 7199s to the more plentiful and inexpensive 6U8As. Also replaced mis-matched resistors on the Cathodyne phase inverters to bring them into balance.



There you have it, as succinctly as only Lane could say it. Lane will have to fill you in on the nitty-gritty details if he's so moved. All I know is I went from "shit" to this work in progress:






Note the Technics SL-23 turntable which also benefited from a capacitor-refresh courtesy, again, of the House o' Sparber, to stabilize the speed after 34 years since Panasonic cranked it out. I scored a pair of Polk Audio Monitor 50's for an absolute steal on e-bay and have been in High Fidelity bliss for a few weeks now. Crystal clear at any volume, no hum, hiss, whistles or what-have-you and surprisingly *L O U D.* In fact, it's so damned good, I've been listening to it constantly instead of posting this, which given the amazing work Lane performed to bring my rig back from the dead, by all rights I should have done right away. Lane, my sincerest apologies, buddy; I just couldn't tear myself away from the thing to get this done.

In the end, what's important to me is that Lane gave me a piece of my Dad back after 13 years, and for that I will be forever in debt to him. He's talented, tenacious, honest, dependable and too damned modest, if you ask me; he would never puff his chest about something like this, despite the fact that he absolutely deserves to, so I'm doing it for him whether he likes it or not. I'm gonna lay off him for a while before I dump my recently-humming Univox on him, but I_ am_ going to encourage any of you who've got an amp that's acting up to contact Lane and have him cure what ails you. He's 3 for 3 with me and 2 of those projects have been _incredibly_ involved and, more to the point, personally important stuff. Are there other guys who could do this, who know just as much as or more than lane does or are just as talented? I have no idea. I'd guess there _probably_ are, but that doesn't mean I would so much as let them plug my stuff into the wall, much less work on my stuff or have to deal with them. Not only am I pretty picky about who I do business with, but the patience and talent this took to achieve is so far beyond my understanding that what anyone else could do doesn't really matter to me who else could do what. The amp is perfect now, that's all I need to know and Lane did it for me.

Unreal. Just.................unreal.

I really just don't know what else to say. Kudos, Lane, you're the man.


----------



## Lane Sparber

Erm...well...um...I am TOTALLY speechless, Michael. Wow. 

I am THRILLED that you are getting such enjoyment from this, but I re-assert that I am a simple tech...no more, no less. I just do what I do like any other tech on here and that's about as "magical" as I get. 

Once again, I am humbled beyond measure by your kind words...they are GREATLY appreciated.

-Lane


----------



## solarburn

Awesome read...awesome outcome! Sounds like you put a smile on sumbodies mug Lane. That's a great talent you have there. Way to use it!


----------



## Michael1987xl

Lane Sparber said:


> Once again, I am humbled beyond measure by your kind words.



Like I said, man, "too damned modest". 

The amp is amazing; take a bow, you deserve it. 

That is all.


----------



## lespaul339

Thats a cool story Michael, and good job Lane!


----------



## Adwex

How cool is it, that you found the actual amplifier your dad had, not just the same model. 
Awesome story.

I can kinda relate...my dad had an interest in audio when I was young, and I certainly inherited the interest. We had some nice speakers and a Teac reel to reel, which all "became" mine as a teenager. I listened to music through that equipment for countless hours, for years. The speakers are still at their house, and they will eventually be in mine someday. I can fully understand how you feel, Michael.

Kudos to you Lane.


----------



## Lane Sparber

Hey, gang!

Just popping in for a sec to let anyone interested know that I've put some new photos up in my FB "workbench" section for your collective enjoyment and/or partial boredom alleviation.  This is a large part of why I've been posting a bit less here on the forum - I have been crazy busy with the day job, a new nephew, and the guitar and amp shop has been off the hook lately, for some reason. It seems that the madness _might_ be letting up soon, and when (and if!) it does I'll get some new blogs going. In the meantime, here's the link again, and feel free to comment...good bad or indifferent! 

Lane's Workshop | Facebook

-Lane


----------



## solarburn

Lane Sparber said:


> Hey, gang!
> 
> Just popping in for a sec to let anyone interested know that I've put some new photos up in my FB "workbench" section for your collective enjoyment and/or partial boredom alleviation.  This is a large part of why I've been posting a bit less here on the forum - I have been crazy busy with the day job, a new nephew, and the guitar and amp shop has been off the hook lately, for some reason. It seems that the madness _might_ be letting up soon, and when (and if!) it does I'll get some new blogs going. In the meantime, here's the link again, and feel free to comment...good bad or indifferent!
> 
> Lane's Workshop | Facebook
> 
> -Lane



Very cool Lane. Enjoyed the pics of your work area and the amps. I was hop'n to see a shot of you in there so I could see the mug that is the Tech hehe. I don't have a FB account.


----------



## Lane Sparber

solarburnDSL50 said:


> Very cool Lane. Enjoyed the pics of your work area and the amps. I was hop'n to see a shot of you in there so I could see the mug that is the Tech hehe. I don't have a FB account.



YOU ASKED FOR IT (don't say I didn't warn you, Joe!):






For clarification...I am on the LEFT! 

-Lane


----------



## solarburn

Lane Sparber said:


> YOU ASKED FOR IT (don't say I didn't warn you, Joe!):
> 
> 
> 
> 
> 
> 
> For clarification...I am on the LEFT!
> 
> -Lane



Hahaha! You headed me off. I was going to say you look just like Ozzy!!!!!!

Good to meet the man Lane.


----------



## Lane Sparber

solarburnDSL50 said:


> Hahaha! You headed me off. I was going to say you look just like Ozzy!!!!!!
> 
> Good to meet the man Lane.





-Lane


----------



## Lane Sparber

Just purely for reference, here are a couple of signal flow charts for the DSL 50 and DSL 100 that I hope you find useful/effective. I reserve the right to correct and update them as necessary! 

DSL 50:






DSL 100:






Maybe this can help to clear up some questions!

-Lane


----------



## chuckharmonjr

Fantastic! Thanks Lane. Makes much better sense now.


----------



## Lane Sparber

chuckharmonjr said:


> Fantastic! Thanks Lane. Makes much better sense now.



Glad you like it...because in this instance, you were one of the chief inspirations for me creating these documents. 

-Lane


----------



## Adwex

Nice job, Lane, thank you for the effort.

Not to give you any more work, but I'd love to see one for the Jubilee, as I know it has a somewhat unique circuit. I've stared at the 2555 schematic many times, but amplifier circuits are not my specialty.


----------



## Lane Sparber

Adwex said:


> Nice job, Lane, thank you for the effort.
> 
> Not to give you any more work, but I'd love to see one for the Jubilee, as I know it has a somewhat unique circuit. I've stared at the 2555 schematic many times, but amplifier circuits are not my specialty.








-Lane


----------



## duffhuff

Lane Sparber said:


> -Lane



Nice! 
There's an 'interesting' tone stack on these isn't there! tandem bass pot? hmm!


----------



## Lane Sparber

duffhuff said:


> Nice!
> There's an 'interesting' tone stack on these isn't there! tandem bass pot? hmm!



Indeed. The unique tone stack is just one of the many things that make this amp my all time favorite!

-Lane


----------



## TwinACStacks

Lane. Any Idea what the HT voltage for a Vox AC30CC2 PT should be? Vox is pretty standard 280/280 for most reissues. I'm thinking of Trying the Magnetic Components Stuff in my CC2. Thought maybe you might know.

 TWIN


----------



## Lane Sparber

TwinACStacks said:


> Lane. Any Idea what the HT voltage for a Vox AC30CC2 PT should be? Vox is pretty standard 280/280 for most reissues. I'm thinking of Trying the Magnetic Components Stuff in my CC2. Thought maybe you might know.
> 
> TWIN



The Vox AC30CC2 power transformer's B+ winding is wound a bit hotter - it's spec'd at 295.5-0-295.5 according to the scheme. When rectified by the GZ34, this yields you about 340v.

Link:

http://www.bymcomunicacion.com/pvecino/Esquema_Vox_AC30CC2_CC2X.pdf

This what you needed?

-Lane


----------



## TwinACStacks

Thanx Lane. Answered My question. There is a Low voltage tap on the CC2 transformer that the Mag. Components Trans doesn't Have. Oh well I can probably swap out the OT anyways.

 TWIN


----------



## Lane Sparber

TwinACStacks said:


> Thanx Lane. Answered My question. There is a Low voltage tap on the CC2 transformer that the Mag. Components Trans doesn't Have. Oh well I can probably swap out the OT anyways.
> 
> TWIN



Which tap are you speaking of? There are three taps on the CC2 tranny: HT, 5v for the GZ34 heater and 6.3v for the other heaters. Which one does the Mag not have?

-Lane


----------



## TwinACStacks

Lane look closely at the PT on Page 5 schematic. Note at the top of the Trans Pic there is a note that says the Heater taps are NOT shown. There appears to be a Secondary tap around 25V (Bottom Tap). Probably like a DSL for LV effects.

 TWIN


----------



## Lane Sparber

TwinACStacks said:


> Lane look closely at the PT on Page 5 schematic. Note at the top of the Trans Pic there is a note that says the Heater taps are NOT shown. There appears to be a Secondary tap around 25V (Bottom Tap). Probably like a DSL for LV effects.
> 
> TWIN



D'OH! Of COURSE! For the op-amps/lv circuitry. BAD Lane. BAD BAD BAD Lane.

You could always have Heyboer custom wind you a new tranny!

-Lane


----------



## TwinACStacks

Lane Sparber said:


> D'OH! Of COURSE! For the op-amps/lv circuitry. BAD Lane. BAD BAD BAD Lane.
> 
> You could always have Heyboer custom wind you a new tranny!
> 
> -Lane



Ya think It would be worth it?

 TWIN


----------



## Lane Sparber

They make EXCELLENT stuff, and they're nice folks, as well. What's your issue with the current (pun intended) PT?

-Lane


----------



## j2112c

Sorry, Lane, sorry Twin I know you are in the middle of a chat... I do not mean to butt into your chat, but when you get a moment could you have a think about this question for me?

I posted this question in the workbench but did not get a corrective answer...
I have a 2061x, sounds great clean and crunched up... but up to 10 the single notes have a 'fizz' to their decay.. it is in the chords too, but obviously most noticeable when soloing single notes - it is a nasty tone... which is a shame as the amp in every other way including a loud 20w output is a nice package.

So what causes fizzy gain on the notes?
What can be done to mod it out of the amp?

I heard Papus and his 2061x with a Swank Motee cascade mod on You Tube.. it sounded great, no fizz.. when I asked him he said the fizz was only eliminated by mic placement.. so I assume he has it too..

Any ideas Lane or the guys?
I am not sure this is the correct use of your blogg as technical helpline, excuse me if I am being cheeky!


----------



## Lane Sparber

j2112c said:


> Sorry, Lane, sorry Twin I know you are in the middle of a chat... I do not mean to butt into your chat, but when you get a moment could you have a think about this question for me?
> 
> I posted this question in the workbench but did not get a corrective answer...
> I have a 2061x, sounds great clean and crunched up... but up to 10 the single notes have a 'fizz' to their decay.. it is in the chords too, but obviously most noticeable when soloing single notes - it is a nasty tone... which is a shame as the amp in every other way including a loud 20w output is a nice package.
> 
> So what causes fizzy gain on the notes?
> What can be done to mod it out of the amp?
> 
> I heard Papus and his 2061x with a Swank Motee cascade mod on You Tube.. it sounded great, no fizz.. when I asked him he said the fizz was only eliminated by mic placement.. so I assume he has it too..
> 
> Any ideas Lane or the guys?
> I am not sure this is the correct use of your blogg as technical helpline, excuse me if I am being cheeky!



I avoided your original thread initially because this is a VERY subjective subject, and could lead to endless tone/chasing and modding. 

That being said, MY take on "fizz" is that it is usually caused by too much gain too early + too much high mid/high frequencies in the signal. Other techs might disagree with this, but that's just how I feel about it...and it's MY blog, innit? 

Do you use one channel over the other? Which one do you plug into? Jumper them? All of this makes a difference as to how we approach modding this amp. Also, as this is basically a NMV single channel amp, any changes we make WILL also affect the clean tone, so be advised.

Now then...assuming that THIS is the correct schematic:

http://www.drtube.com/schematics/marshall/1917.gif

...then there are a couple of methods/approaches you COULD try. You could try upping one (or both) coupling caps after the 100k plate resistors on V1a and V1b to .047s. This will allow more bass frequencies through to the phase inverter for a more wide range and balanced signal. It MIGHT get too mushy though -especially when cranked- so as each one of these caps is fed by a single channel input, you might wanna change out just ONE and try a/bing and jumpering and see what happens.

Also, you could change one or both 500pf caps in the tone circuits to 820pfs to attenuate a lower high frequency shelf via the volume knob...that might also work. 

If it's simply too much gain that's causing the "fizz", you could lower one (or both) of the 100k plate load resistors on V1 to 82k and see what that gets you.

Finally, you could try the cascade mod that Buggs linked you to in your original thread. Separating the preamp cathode circuits like that will open up many more tone/gain shaping opportunities than the shared cathode arrangement that's in there now.

Finally, you might want to try a different speaker. THAT might get you what you want without even cracking the amp. The speaker is one of THE most important factors in the amp. We can talk later about options should you decide to go this route.

THE FINE PRINT (A re-iteration):

As I said above, this is all subjective. What causes fizz (and makes one guy hear said fizz and another guy NOT hear fizz out of the same gear) is a tricky thing. Be prepared to experiment; it's not likely that any of the mods above will be a "silver bullet" solution...most likely it will be two or three of them in tandem - if they work for you at all. Welcome to the wonderful world of tone shaping an amp!  When I do this kind of thing, I insist on the client being there in the room with me with HIS guitar and HIS speaker cabinet and signal chain, as what sounds good to ME might not be what he's after. I'm working for _his_ hears, not mine!

Good luck, and I'm sure if I've erred here other techs will jump in...I invite it!

Let me know how it goes!

-Lane

P.S. It's the end of a VERY long day here in Sparberville, so forgive me if anything's not clear or there are any inaccuracies in the above post.


----------



## j2112c

Thanks for the input Lane,  the amp was going through a stack of 1960 gt75s both channels jumped at full pelt... not subtle I know... 
I have a V30 in a cab here, I will try that first.

Channels were jumped, so I will also try using one the lead channel to see it goes, if it does then I will know which circuit it is in and if I can mix the second channel in without getting fizz.

If these do not work I will take the schematic and the suggestions to a mate of mine and see if we can try a few of these things and perhaps do the SM mod at the same time.
Yes the mod Buggs gave me is the Swank Motee one Papus had done... it sounded good and other forums seem to think it is a good move without losing a lot of the amps character or ability to clean up on the guitar volume. 


It would be nice to get it sorted as it is not a big lump to carry to practice but louder than Hades.

Thanks again for your time Lane.


----------



## Lane Sparber

No problem, John! That's why I'm here.

One more thing...you could also try the standard Marshall trick of a 100pf cap between the plate and cathode of V1a and/or V1b.

Happy experimenting!

-Lane


----------



## j2112c

Hello, back again...

My 2204 appears to have lost a bit of gain. 

When I first had it no booster required monster gain. 
This past few weeks I thought it might just be my ears but the gain felt more like a 1987 than a 2204... solos were lower gained so choked a little.. I thought it might just be me, but no I have videos of it previously and it was definitely meatier then.

It was new 18 months ago..(isn't that so cool new 2204) ...can the bias drift.. perhaps a little cooler so causing lower gain?

Do the components have any sort of breaking in and dropping off like the caps? 

What do you think?




I am going over to a town about 20 minutes drive from Marshall at the end of the month so I will take the head in for a check over.. but I wondered if you had any thoughts on this.


----------



## Adwex

Sorry Lane, I gotta step in here for a sec....

John, you're not considering modding the Pink Panther, are you?


----------



## j2112c

Adwex said:


> Sorry Lane, I gotta step in here for a sec....
> 
> John, you're not considering modding the Pink Panther, are you?



 Oh God no mate, do not fret, she will remain as from the factory for all my lifetime.

It is simply that she has lost a bit of gain. Chords are not so noticable, but solos you can tell... I am needing a booster now, which I was not before..

I was wondering if it had just broken in, when I go over to Marshall at the end of the month I will get them to check it over and rebias if required... I just wondered what Lane thought... of the gain falling, if it is a drift in bias, tubes or my ears!

Thanks for your concern, it is nice (reassuring) to know that if I was ever daft enough to mess with the Pink Panther, I have a friend that would talk sense to me!


----------



## james1100

Would that not be sacrilegious to mod that pink beauty


----------



## Lane Sparber

Try the easiest solution first - all new tubes and a fresh bias. There are no rules governing tube life expectancy, and I'd look there first...or just wait for it's checkup. At the very least you can try some new preamp tubes and see what -if anything- that buys you. 

-Lane


----------



## Adwex

james1100 said:


> Would that not be sacrilegious to mod that pink beauty



It would be a crime. That amp was not a production model.


----------



## j2112c

james1100 said:


> Would that not be sacrilegious to mod that pink beauty



Agreed.




Lane Sparber said:


> Try the easiest solution first - all new tubes and a fresh bias. There are no rules governing tube life expectancy, and I'd look there first...or just wait for it's checkup. At the very least you can try some new preamp tubes and see what -if anything- that buys you.
> 
> -Lane



OK Lane that is fine, it is good to have an opinion on it, that it could be a simple re-tube and re-bias... I will book it in with Marshall in the morning for one of their single day appointments and ask them to check it over with a view to the gain drop.
I will be able to test it there, that day.

Can I ask one more thing..?

I know it is a minefield on tubes.. but is there anything you would recommend.. simple for me.. if I go to the Tube thread I will get 1001 different recommendations of the last of the Telefunkens found on a 1960s space shuttle prototype that I should get at 13,456 bucks.


Anything simple, cheap and effective for a 2204?

Also.. I wonder as I have an effects loop in the PP if I also changed the settings for the effects rack at any point and had some boost... I wonder if the loop was jumped it might make a difference as it does in some other Marshalls?
I have no idea how it was wired up as it was retro fitted after the amp was done.


----------



## Lane Sparber

I am not a metalhead...my tastes are more punk, so take this with a grain of salt, but I like cp Tung-Sols and ElectroHarmonix pres in that order. For power tubes, try JJ EL34Ls...they are relatively cheap and have sounded great in every amp I've used them in. Just my two cents here.

As to the loop, what it does or does not do when jumpered all depends on the design of the loop itself, and it sounds like (pun intended) we don't have that info. Just go ahead and jumper it to hear what it does. You certainly won't hurt anything.

-Lane


----------



## j2112c

Lane Sparber said:


> I am not a metalhead...my tastes are more punk, so take this with a grain of salt, but I like cp Tung-Sols and ElectroHarmonix pres in that order. For power tubes, try JJ EL34Ls...they are relatively cheap and have sounded great in every amp I've used them in. Just my two cents here.
> 
> As to the loop, what it does or does not do when jumpered all depends on the design of the loop itself, and it sounds like (pun intended) we don't have that info. Just go ahead and jumper it to hear what it does. You certainly won't hurt anything.
> 
> -Lane



Thanks for that simple tube advice a blessing. 
No offence to the boys that model their sound by a variety of collectable and rare NOS tubes, but for me, if the gain is about the same, they are fine.

JJsEL34s are easy to get over here, Watford Valves... I will check out the others.


I will see what happens with the loop tomorrow, I will let you know if there is any difference or none. Cheers.


----------



## jcmjmp

Much prefer the SED =C= over the JJ EL34L. Also prefer the Tung Sol EL34B.


----------



## Lane Sparber

jcmjmp said:


> Much prefer the SED =C= over the JJ EL34L. Also prefer the Tung Sol EL34B.



Winged Cs have gotten way too expensive for most of my customers, JCM, although I love them too.

-Lane


----------



## TwinACStacks

Hey Lane, I need to change some values of a few caps in my Vox AC30 to more vintage specs. I haven't opened it up yet, but I need to change a Couple of Bright Caps and one in the Normal channel tone stack. The values are 68, 47, and 100pf. All I can seem to locate in these small values are Mica and Ceramic. Any suggestions about what type to Use?

 TWIN


----------



## Lane Sparber

TwinACStacks said:


> Hey Lane, I need to change some values of a few caps in my Vox AC30 to more vintage specs. I haven't opened it up yet, but I need to change a Couple of Bright Caps and one in the Normal channel tone stack. The values are 68, 47, and 100pf. All I can seem to locate in these small values are Mica and Ceramic. Any suggestions about what type to Use?
> 
> TWIN



Conventional wisdom states that ceramic caps are more "grainy" and "gritty" sounding whereas the silver micas are reportedly "smoother" and have a more "high-fi" sound to them. This is all subjective of course, but in my experience, these maxims have indeed shown themselves to be accurate. I almost always use silver micas myself, unless I am replacing what's there EXACTLY in a vintage amp...like a Fender. In YOUR case, Twin, if I recall correctly the vintage AC30s used wax covered silver mica caps for those components, and since IMHO the micas sound better anyway, I think that that's what you should use.

Hope this helps!

-Lane


----------



## TwinACStacks

Thanks Lane. Your advice is deeply appreciated.

 TWIN


----------



## TradAmpGuy

I use micas for all small value stuff. They're cheap enough that you dont need to go ceramic.

Hey Lane, have you tried Sozo caps? If so how'd you like them? Ive been using Dijons from Mojo for my British stuff and was just curious.


----------



## TwinACStacks

Hey Lane, I'm wrestling with a Mod description for the AC30cc It involves putting a 68pf cap across lugs 1 & 2 ??? of the Normal Channel Vol. Pot. Does that mean Wiper to ground or wiper to the other leg that goes to the Trace with R49 on it?


http://www.bymcomunicacion.com/pveci...30CC2_CC2X.pdf

Thanx, TWIN


----------



## jcmjmp

I just ordered a bunch of Murata Ceramics for my 1987x rebuild. Should be better than the stock stuff for sure. Went with Wimas in some spots and the old MKTs for the rest.


----------



## TwinACStacks

twinacstacks said:


> hey lane, i'm wrestling with a mod description for the ac30cc it involves putting a 68pf cap across lugs 1 & 2 ??? Of the normal channel vol. Pot. Does that mean wiper to ground or wiper to the other leg that goes to the trace with r49 on it?
> 
> 
> http://www.bymcomunicacion.com/pveci...30cc2_cc2x.pdf
> 
> thanx, twin



bump

 TWIN


----------



## jcmjmp

Twin - That means accross the middle lug and the lug that is connected to the cct, the 3rd one going to ground.


----------



## TwinACStacks

jcmjmp said:


> Twin - That means accross the middle lug and the lug that is connected to the cct, the 3rd one going to ground.



Thanx jc. I didn't quite know how to interpret that, as I've also preformed a mod on the DSL where Joey Had me wire a resistor middle to Ground.

 TWIN


----------



## Lane Sparber

jcmjmp said:


> Twin - That means accross the middle lug and the lug that is connected to the cct, the 3rd one going to ground.



Thanks for holding down the fort for me while I was away, JCM! Much appreciated. 

-Lane


----------



## Lane Sparber

TradAmpGuy said:


> Hey Lane, have you tried Sozo caps? If so how'd you like them? Ive been using Dijons from Mojo for my British stuff and was just curious.



Nope...I've never used them, but Jon has. He used to use them all the time, so I'd PM him for his thoughts. 

-Lane


----------



## TwinACStacks

Lane Sparber said:


> Thanks for holding down the fort for me while I was away, JCM! Much appreciated.
> 
> -Lane




( folds arms and taps foot)

AND where were you MISTER?

 TWIN


----------



## TwinACStacks

Lane Sparber said:


> Nope...I've never used them, but Jon has. He used to use them all the time, so I'd PM him for his thoughts.
> 
> -Lane



I've also used them in an 800 mod. I didn't care for the regulars, but the Vintage premium ones are TITS. I'm using them in my Vox AC30CC mod.

*sniff-sniff* Anyone smell cork?

 TWIN


----------



## Lane Sparber

TwinACStacks said:


> ( folds arms and taps foot)
> 
> AND where were you MISTER?
> 
> TWIN



Erm...holiday. 

-Lane


----------



## jcmjmp

TwinACStacks said:


> I've also used them in an 800 mod. I didn't care for the regulars, but the Vintage premium ones are TITS. I'm using them in my Vox AC30CC mod.
> 
> *sniff-sniff* Anyone smell cork?
> 
> TWIN



Twin - please start another thread for your Vox AC30CC. 

I have one and would be interested to see what you do to yours and how you like the outcome. Make sure you put some pics up too.

The only thing I did on mine was snip the treble bleed cap on the TB channel volume. I have some other mods that affect the loop. Thought of doing an OT/PT swap but wasn't sure if it was worth it.

Aren't those things well built? I was really impressed with them.


----------



## TwinACStacks

Lane here is a Pic of a Mod done to an AC30CC by another tech. My question involves the Values of the 2 circled Caps they are C17 &C18 for the Grids V3. Along side of them are C19 &20 for the Plates. *ALL FOUR* are supposed to be .1 uf--the two circled however, (C17 & 18), are visably smaller. Any Idea why he would decrease the Value of Grid caps, and what Value would he use? They look to be .022 or .047 in size, the Pic is to blurred to read them.







Thanx, TWIN


----------



## Lane Sparber

TwinACStacks said:


> Lane here is a Pic of a Mod done to an AC30CC by another tech. My question involves the Values of the 2 circled Caps they are C17 &C18 for the Grids V3. Along side of them are C19 &20 for the Plates. *ALL FOUR* are supposed to be .1 uf--the two circled however are visably smaller. Any Idea why he would decrease the Value of Grid caps, and what Value would he use? They look to be .022 or .047 in size.
> 
> 
> 
> 
> 
> 
> 
> Thanx, TWIN



Decreasing the value of those caps will cut some bass out of the signal. Without knowing specifics, I suspect the tech was trying to tame some "flabbiness" out of the sound and tighten up the bass response by raising the value of those caps. As to the values, your guesses seem accurate, becuase if you're going to raise values from a .1uf, a .047 and then .022 are the next common values in line. My two cents is that if you have too much bass and want to tighten the amp up, try it. You just might like it. 

-Lane


----------



## TwinACStacks

Lane Sparber said:


> Decreasing the value of those caps will cut some bass out of the signal. Without knowing specifics, I suspect the tech was trying to tame some "flabbiness" out of the sound and tighten up the bass response by raising the value of those caps. As to the values, your guesses seem accurate, becuase if you're going to raise values from a .1uf, a .047 and then .022 are the next common values in line. My two cents is that if you like the sound, leave them. If not and you want more bass, restore the stock values.
> 
> -Lane




Thanx Lane, BTW: that is not my AC30CC But I'm using Lyle's mod pic as a reference when I noticed the cap sizes in the Pic didn't jive with the Values on the schematic. I think I'll go with stock values first and If I find it's too Flabby, (which isn't my description of an AC30 at all), I'll experiment with the Two other values later.

AS always Your advice is greatly Appreciated, as are all our Tech's here on the forum. You guys are just GREAT!!!!

 TWIN


----------



## Lane Sparber

TwinACStacks said:


> Thanx Lane, BTW: that is not my AC30CC But I'm using Lyle's mod pic as a reference when I noticed the cap sizes in the Pic didn't jive with the Values on the schematic. I think I'll go with stock values first and If I find it's too Flabby, (which isn't my description of an AC30 at all), I'll experiment with the Two other values later.
> 
> AS always Your advice is greatly Appreciated, as are all our Tech's here on the forum. You guys are just GREAT!!!!
> 
> TWIN



Yeah...I realized that and edited my post. I never thought of AC30s as flabby either, but you never know what speakers etc. he is using. 

-Lane


----------



## jcmjmp

Twin - you just doing the Lyle Caldwell mods listed in the Vintage Amps forum? That's pretty simple. I probably wouldn't go with sozos or mallorys though and just stick to MKTs


----------



## TwinACStacks

jcmjmp said:


> Twin - you just doing the Lyle Caldwell mods listed in the Vintage Amps forum? That's pretty simple. I probably wouldn't go with sozos or mallorys though and just stick to MKTs



Most of 'em, don't need to do the F/X loop it's all ready done. I still have the Sozos I need left over from the 800. I'm also putting some Carbon Comps in the signal path.

Might as well "Vintage it up a bit". I can replace the choke and OT with Magnetic component. It will sound EPIC.

Daddy needs a Choke and Xformer for Father's Day......

 TWIN


----------



## TwinACStacks

jcmjmp said:


> Twin - please start another thread for your Vox AC30CC.
> 
> I have one and would be interested to see what you do to yours and how you like the outcome. Make sure you put some pics up too.
> 
> The only thing I did on mine was snip the treble bleed cap on the TB channel volume. I have some other mods that affect the loop. Thought of doing an OT/PT swap but wasn't sure if it was worth it.
> 
> Aren't those things well built? I was really impressed with them.



Hey JC. I missed this post completely. I think they are exceptionally well built. That is why I favor the CC's. They used some cheaper (softer) screws on the cosmetics which everyone had a fit about because they were too heavy-handed with their screwdrivers but other than that there were actually very few issues with these amps. The PCBs are outstanding in thickness and quality. JMHO

I will post pics as I go along. I'm not sure yet about replacing the OT and Choke but Lyle and others say it makes a lot of difference. I'm going to use Magnetic Components rather than Mercury if I swap them though. I feel the MC stuff is closer to vintage contruction then anything MM puts out.

 TWIN


----------



## jcmjmp

TwinACStacks said:


> I will post pics as I go along. I'm not sure yet about replacing the OT and Choke but Lyle and others say it makes a lot of difference. I'm going to use Magnetic Components rather than Mercury if I swap them though. I feel the MC stuff is closer to vintage contruction then anything MM puts out.
> 
> TWIN



If I change my OT out, I'll have a custom spec'd one made from Heyboer.


----------



## TradAmpGuy

Lane Sparber said:


> Nope...I've never used them, but Jon has. He used to use them all the time, so I'd PM him for his thoughts.
> 
> -Lane



Thanks Lane :cool2:


----------



## Lane Sparber

Here's a link to a new blog elsewhere on the forum, for those who care to see what I've been up to...

http://www.marshallforum.com/marshall-amps/17524-1987x-help.html

I hope you enjoy it. 

-Lane


----------



## Lane Sparber

*Vox Hi-Jinx, Part One*

Hello again, Lane’s Blog readers!

I was recently presented with the rare opportunity to revitalize an early 60s vintage Vox AC30/6 non-Top Boost model. I figured it would be an excellent chance to share my experiences working on this beautiful and rare bird with you.

The objectives of this repair were simple: replace any worn parts, get her in tip top electrical shape again and install the full set of vintage Mullard tubes that the owner had provided (I don’t even want to THINK about what he’d paid for them). Last but NOT least, I was to install the provided top boost module, effectively converting this amp to a full on Top Boost model. This top boost installation will be covered separately in a future blog installment. First, I had to get the amp back to 100% functionality, as it’s my personal philosophy not to mod any broken amps! 

First off, after installing a new Edison plug (the original was a European model), it was time to perform some preliminary tests. The owner had informed me that when the Vox engineers calculated the American voltages and Hertz cycles, they made an error in thinking that we used 50 Hertz instead of 60. This error then resulted in most Vox amps’ power transformers from the period having to be run on a dialed-down voltage regulator or needing to be dialed down on a Variac to compensate for the error. This shouldn't have been an issue anyway, as any transformer wound for 50 hertz is fine for 60. It's going the OTHER way that can cause issues. At any rate, I tested this amp, and with 115vac being fed into the amp (which was what the power transformer was allegedly wound for), I got EXACTLY 6.3 volts on the heaters. Well, so much for that internet theory…at least with THIS particular amp. My findings here do not get us completely out of the woods though, as modern American wall outlets provide 120vac, and most of us have MORE than in our homes and practice spaces. This is bad with any tube amp, but it’s especially problematic with a vintage Vox like this, because they run hot – VERY hot. This client is purchasing a Variac and will run the amp at 108-115vac so that the amp will run happily and safely.

So…now that we have solved that mystery, it was time to begin the re-cap. Here she is pre-surgery:






After removing the back, you have to disconnect the speaker wires in order to fully remove the chassis on it’s slider board. 

In addition to the hazards of high voltages when working on tube equipment, there are OTHER hazards when working on old amps that have not been serviced for years. When I removed the slider board and glanced back up at the chassis, I was greeted with the site of THIS 2.5" long lovely lady:






Don’t worry folks, as she’s been dead for at least 20 years, I’d guess. Still, she gave me quite a start, as that’s hardly what I was expecting to see there!  It's a good thing that I love spiders!

To get back to the task at hand, once we remove the six bolts holding the slider board to the chassis, we can get to the power tubes’ cathode bypass cap and the 32uf post-choke stage filter cap:






This amp had been previously serviced, and the last guy did a pretty great job with the work he’d performed. That was a relief after some previous experiences I’ve had. He did NOT however, change out ALL of the electrolytic caps...even leaving this filter cap stock. Curious.

The main filter cap can is a dual 16uf x 16uf cap. This dual cap came in two different diameters – a 1” and the wider 1.25” diameter cap that all of us Marshall owners are familiar with. As far as I know, the skinnier caps were used on the initial models, and then after a few years they transitioned to the fatter cap. The last tech seems to have had ONLY the skinnier cap, and he had used rolled up paper fastened with glue to the cap in order to get it to fit. While this was an interesting technique, it didn’t hold very well over time, as the cap was loose in the chassis when I got it. That was a VERY bad thing:











Here’s the new F&T I installed with the date written on it. Excuse the handwriting, please!






Here’s a gut shot of all of the new under-chassis caps installed. Notice that they’re MUCH smaller than the originals. That’s not a bad thing in this case, as the caps I used had pretty good ratings in terms of ESL/ESR.






While at this point in the repair discussion, I’d like to point this out to you as a cautionary aside. Take a look at the power transformer:






That nasty yellow stuff is wax that has run out of the transformer due to overheating. Why? Well, a major contributing cause was that this amp had been used consistently with wall voltages of 120vac and up, and this over-voltage caused some of the wax to melt out of the PT’s internal structure. This happens often on vintage Vox amps run off of modern US wall voltages. This owner is VERY lucky, as this PT tested fine, but it could have been fried. THIS is why us techs constantly tell forum members to check their wall voltages! It does make a big difference, as you can see here! Don’t let this happen to you.

Flipping the chassis over, here’s a shot of the power tube sockets:






Look closely. See that red stuff on the contacts of the power tube socket second from the left? That’s the red dye that Vox used on all of the solder joints in the amp when completed. This was to make it easy to tell if the amp was tampered with outside of the factory. This red junk also had a tendency to run and to seep into places where it wasn’t supposed to go. Patience, rubbing alcohol, a #11 X-acto blade and ½ hour later, the sockets were clean.

Having completed this part of the re-cap, I flipped the chassis over yet again in order to finish the job. All that was left was one more dual filter cap and three cathode bypass caps. The old dual filter here was a replacement 8uf x 8uf from Radio Spares, just like the dual 32uf can above that had the paper wrapped around it. I replaced it with a nice new F&T model double secured with hot glue so that it won’t be going anywhere:






Now, to finish up, I installed the three preamp cathode bypassers. They are all 25uf/25volt caps. 1 is on the shared cathode on the “Normal” and “Brilliant” 1st stage preamp tube, one is on the first gain stage cathode of the “Vibrato” channel, and the last capacitor is a cathode bypass on the oscillator circuit for said Vibrato channel. Here they are installed:

The normal/brilliant bypass cap:





Note the two sets of resistors sticking up in an inverse “V” shape on either side of this cap. This is a method used by a lot of techs to add a parallel resistance circuit across a resistor that has drifted off of spec to knock the overall resistance value back down to where it needs to be. I have no problem with this method…AS LONG AS THE OLD RESISTOR THAT’S JUMPERED IS STABLE! This rarely happens, because as the old resistor continues it’s journey towards open-ness, the overall value continues to shift. In all cases here, the original resistor had failed outright (open circuit) and the previous tech had left the vintage component in the amp and solved the problem using this method. As the old resistors were completely dead and would be causing no more problems, I left them as is.

Here’s the first stage Vibrato channel cathode bypasser:






Finally, the oscillator cathode bypass cap:






After forming all of the new caps, everything worked perfectly…EXCEPT that the Vibrato channel’s effect was kind of weak. It worked, but did not have the intensity that I like to see in a healthy tremolo circuit. Upon examining the oscillator circuit, I found that several of the resistors in that circuit had drifted significantly off spec. This wouldn’t do, so I rebuilt the entire oscillator circuit (minus the 3K9 cathode resistor, which WAS still on spec). Here’s what it looked like when I was finished:






Note the jumper I installed between the 4th and 6th terminals from the left on the bottom. This is because the amp originally shipped with a footswitch between these two terminals for the vibrato effect. A previous owner had cut the cord and lost the switch. Sigh. As these contacts need to be connected for the vibrato to work, I installed this wire so that the effect would run. If my client decides to purchase a footswitch at a later date, it would be VERY easy to simply remove the jumper and install the switch.

After the re-build, adjusting the internal “Depth” trimpot yielded sounds ranging from a subtle warble all the way to a chopper-like effect. It sounded epic!

Now that the amp was healthy and electronically sound again, it was time to install the Top Boost module, however I’ll save that for another post…and another day. 

Until next time!

-Lane


----------



## MM54




----------



## Adwex

After reading this blog, I feel inspired to do a better job at whatever I do.

Excellent work, Lane.


----------



## chuckharmonjr

Lane kicks ass...takes names....and documents it well...doesnt he Adam? Hell Id hire him in a New York minute.


----------



## chuckharmonjr

And for the record....Im hiring


----------



## Lane Sparber

Thanks so much for the compliments, guys. For me, it's this _FORUM_ that kicks ass, and that's also why I'm so happy to be a small part of it.

Cheers, brothers! 

-Lane


----------



## MM54

I have a bunch of tube sockets that are pretty corroded (some to the point of being blue), how would you suggest I go about cleaning them up, Lane?


----------



## Lane Sparber

Good question! Here's how I personally go about this job, Matt:

With the amp off and caps drained, use a toothbrush dipped in 91% isopropyl alcohol to gently and carefully scrub the sockets and loosen the crud. Be sure to keep the alcohol contained solely to the corroded areas...no drips or spills in this step, please! Then take the tiniest jewlers's screwdriver you can find and slowly scrape away the corrosion. In addition, a safety pin or a #11 x-Acto blade will work just as well here. Take your time, be extremely patient and careful and you'll see the contacts begin to clean up after a while. 

Next, flush the socket with a GOOD electronics cleaner (NO LUBRICANT) while continuously working the tube into and out of the socket. Finally, make absolutely sure that all of the alcohol has COMPLETELY evaporated before applying any current to the socket. I usually let it dry overnight for safety.

-Lane


----------



## MM54

I'll give that a shot and let you know how it goes. I have an idea for something that may work but I'll test it out first (so nobody here sees it, tries it, and screws something up ) and let you know. The scraping process seems very slow, and I have 44 sockets to clean (with varying number of pins).


----------



## Lane Sparber

So these sockets are loose and uninstalled at the moment? That does change things! 

-Lane


----------



## Lane Sparber

*Vintage Vox Top Boost Module Installation*

Hello, again!

This photo journal will cover the installation of a “Top Boost” module into a vintage Vox AC30. The Top Boost design modification was introduced in about 1961 and for the first year or two of it’s existence, it was added on to existing AC30s as a separate module mounted inside the back of the amplifier. A rectangular cutout was then routed into the back panel in order to provide access to the new bass and treble controls. Later on, the new circuitry was incorporated into the tag board design and the new controls were integrated into the control panel itself, thus eliminating the need to cut into the back panel.

One of my customers recently brought in an early 60s Vox non top boost amp, and he’d also purchased the required module to convert it into a Top Boost model from these good people:

Vintage Pedal Workshop » AC30 Top Boost Unit

Before we get into the actual install, let’s first take a closer look at just what the Top Boost module is and what it does. Here’s the schematic:






Basically, what we have here is a standard full-range gain stage into a cathode follower circuit that then leads to the tone stack. The cathode follower changes the high impedance signal into a lower impedance signal that is strong enough to drive the tone stack with minimal signal degradation. This is why the cathode follower is used here. The tone stack itself is a bit odd in construction as you can see, and rumor has it that the Vox designers simply stole this circuit intact from a Gibson amp design. The bass and treble controls are EXTREMELY interactive. This is to say that adjusting the “treble” control affects the sweep of the “bass” control and vice versa. You’ve really got to play with the controls a bit to get the hang of how they operate, but they do sound great together! 

To install this new circuit, we need to:

1.	Physically mount the bottom of the module to the existing bolt underneath the center of the chassis between said chassis and the slider board.
2.	As the module contains a tube, we need to connect it’s heater into the existing heater string.
3.	Connect the module’s B+ into the existing HT rail at the junction of voltage dropping resistors R10 and R11.
4.	Connect the module’s ground wire to the grounding tab next to V1.
5.	Insert the module into the bright channel’s signal path between the wiper of the volume pot and R9, which carries the final signal to the phase inverter.
6.	Add a 100pf “Bright Cap” to the aforementioned volume pot.
7.	Drill a hole into the chassis for the module’s support screw.

Here’s a schematic I’ve doctored showing all of these insertion points:






Here’s a picture looking at the back of the amp that shows all of the insertion points for the grounding wire, the B+ wire, and where the module’s heater wires will be attached.






Now, let’s do it!

First, I soldered the B+ wire and the heaters to their respective terminals. Note that the heater wires on the module are blue and yellow, which match the color code of the amp’s existing heater string. Thus we simply solder the blue wire to pins 4/5 on V2, and the yellow wire goes to pin 9. Here’s what this step looks like completed:






Note that I’ve dressed the heater wires out and away from the tag board in order to keep induced noise from the heater string to a minimum.

Now we can attach the black ground wire to the aforementioned grounding tab at V1. I ran this wire UNDER the tag board for cleanliness. You can see how it turned out here (note that there are now TWO black wires attached to the bottom solder lug underneath the nut):






Now that the module has it’s B+, grounding and heater wiring straightened out, we can jump it into the signal path. As this module is inserted between R9 and the volume pot wiper, first we unsolder R9 from the brilliant channel volume pot. Here’s the pot pre-mod – it’s the one on the LEFT in this picture:






In the following photo, I’ve connected the “hot” of the shielded cable going to the module’s pin 2 input grid to the volume pot wiper, and the cable’s ground connects to the pots’ grounding buss, as you can clearly see here:






Also note that I’ve also installed the silver mica 100pf bright cap across the two “hot” terminals of the pot. Actually, the above picture is of the fully completed mod (output wire to R9 is on the right), but here's how I did it:

To connect the other shielded cable from the module’s “treble” pot directly to R9, I stripped away the end’s shield and covered it with heat shrink tubing for cleanliness and to quell any accidental shorts due to exposed shielding wires. Also note that I’ve slid the final piece of shrink wrap over R9’s lead to insulate the final joint in the next step:






Finally, here’s the joint with it’s shrink wrap fastened:






Now, we simply drill (and counter-sink) the hole for the top mounting screw and attach it. Here’s the completed modification:






Normally, the next step would be to rout out the rectangular hole in the back panel for control access. However, since this is a vintage amp we didn’t want to do any permanent alterations outside of drilling the one tiny hole for the top screw (which is covered by the back panel anyway). This client has ordered a reproduction cabinet and back panel in a vintage correct “fawn” color, and it already has the cutout in the back panel done for us. This way, we can keep the original cabinet fully intact and at the same time preserve it from further wear and tear. He’s brining it with him when he picks up the amp, and I'll post pics once I get the amplifier fully re-assembled.

This amp sounds AMAZING, and the addition of this module really made it’s “Brilliant” channel sing. I hope this has helped you understand both what’s going on in the circuit as well as how to physically mount the module. As you can see, it’s not TOO hard, and the amp really roars now. 

Cheers, folks, and as usual feel free to post if you have any questions, comments or rants!

-Lane

P.S. - Here's a GREAT reference link for all of you Voxophiles out there!

http://www.blueguitar.org/new/articles/other/topboost.pdf


----------



## MM54

Lane Sparber said:


> So these sockets are loose and uninstalled at the moment? That does change things!
> 
> -Lane



Nope, they're installed and wired up in-circuit


----------



## Nu_Majorguy

Hey Lane, you seem to be the "go to guy" here could you explain ultralinear is, I don't get it?


----------



## Lane Sparber

Hey!

Simply put, in an ultra linear output configuration, the screens on the power tubes are regulated directly by taps on the output transformer primary and NOT a separate node on the HT rail. Whereas in most "normal" output configurations the screens are regulated by the screen resistors, an UL design is a way of directly inducing negative feedback to the screens which makes the response more linear (less distortion). It's also important to note that UL designs HATE power tube clipping, and the input signal to the output stage must be regulated to avoid this.

Simply put: 

Regular Marshall (guitar amp) Output stage: Yummy warm power section clipping.

Ultralinear Output Stage: Ultra clean, ultra powerful hi-fi sound. This is why it's not often used for us distortion login' guitar nuts, although the Majors do sound GREAT...just...different!

Does this help?

-Lane


----------



## Buggs.Crosby

Lane.....have you ever tried a welder's torch tip wire brush to clean sockets?
they would seem to be perfect for cleaning them


----------



## Lane Sparber

Buggs.Crosby said:


> Lane.....have you ever tried a welder's torch tip wire brush to clean sockets?
> they would seem to be perfect for cleaning them



No, I haven't. Great idea, Buggs! Thanks!

-Lane


----------



## Nu_Majorguy

Lane Sparber said:


> Hey!
> 
> Simply put, in an ultra linear output configuration, the screens on the power tubes are regulated directly by taps on the output transformer primary and NOT a separate node on the HT rail. Whereas in most "normal" output configurations the screens are regulated by the screen resistors, an UL design is a way of directly inducing negative feedback to the screens which makes the response more linear (less distortion). It's also important to note that UL designs HATE power tube clipping, and the input signal to the output stage must be regulated to avoid this.
> 
> Simply put:
> 
> Regular Marshall (guitar amp) Output stage: Yummy warm power section clipping.
> 
> Ultralinear Output Stage: Ultra clean, ultra powerful hi-fi sound. This is why it's not often used for us distortion login' guitar nuts, although the Majors do sound GREAT...just...different!
> 
> Does this help?
> 
> -Lane



Thanks very much Lane, very helpful. Do you know why the Marshall Major's output is ultralinear?


----------



## Lane Sparber

I have no idea WHY they decided to use this scheme...maybe MajorNut would know. 

-Lane


----------



## jcmjmp

MM54 said:


> Nope, they're installed and wired up in-circuit



Ha! I'm actually working on restoring one of these right now. They're a real pain to debug and mine has a problem in the GE test. Complete rats nest.


----------



## thelorddread

lane

wow! amazing stuff. 
this was the first time i read this stuff and it was great. 
you had answered a simple preamp question for me in another thread. 
thanks! 

i have some questions: how did you start and what has helped you
the most? im currently in school for EE but im stopping at an associates. 
cant afford more school plus im 35 now so you know...

oh and i too was a huge alkaline trio fan. not so much these days, but 
i was totally obsessed with them. those first 4 albums or so were amazing. 
maybe we should get that amp back to skiba!


----------



## Buggs.Crosby

Lane Sparber said:


> No, I haven't. Great idea, Buggs! Thanks!
> 
> -Lane



Thanks....naa....just surprised i have never seen it posted and wondered if it was tried.....thank MM for posting the original question....as he brought it to mind


----------



## Lane Sparber

thelorddread said:


> lane
> 
> i have some questions: how did you start and what has helped you
> the most? im currently in school for EE but im stopping at an associates.
> cant afford more school plus im 35 now so you know...



I started out because as a lower, lower, _lower_ middle class kid in Kentucky, I had few people around to service my gear when it failed, and I usually couldn't afford to fix things when they broke down. I grew up on the blues and punk rock, so in turn I am VERY demanding of (and abusive to) my gear. In my case, necessity was the mother of self-discovery in a way, because I discovered through these ordeals that I had some small propensity to fix things. I had always gotten in trouble taking apart and breaking things around the house to find out how they worked, and that habit still haunts me to this day. I grabbed every book and article I could find on amplifier and guitar maintenance and ran with it. No one is ever really done learning, and my journey is far from complete, but I do love helping others when I can.



thelorddread said:


> oh and i too was a huge alkaline trio fan. not so much these days, but
> i was totally obsessed with them. those first 4 albums or so were amazing.
> maybe we should get that amp back to skiba!



The first four albums were _incredible_, and after that...well, it's hit or miss with me. I would love to have Skiba sign and authenticate that amp someday. I doubt it's gonna happen, but I can dream, can't I?

-Lane


----------



## yladrd61

I can make it work, however Lane can make it right !!!!! \m/> <\m/


----------



## TwinACStacks

*Re: Vintage Vox Top Boost Module Installation*



Lane Sparber said:


> Hello, again!
> 
> This photo journal will cover the installation of a “Top Boost” module into a vintage Vox AC30. The Top Boost design modification was introduced in about 1961 and for the first year or two of it’s existence, it was added on to existing AC30s as a separate module mounted inside the back of the amplifier. A rectangular cutout was then routed into the back panel in order to provide access to the new bass and treble controls. Later on, the new circuitry was incorporated into the tag board design and the new controls were integrated into the control panel itself, thus eliminating the need to cut into the back panel.
> 
> One of my customers recently brought in an early 60s Vox non top boost amp, and he’d also purchased the required module to convert it into a Top Boost model from these good people:
> 
> Vintage Pedal Workshop » AC30 Top Boost Unit
> 
> Before we get into the actual install, let’s first take a closer look at just what the Top Boost module is and what it does. Here’s the schematic:
> 
> 
> 
> 
> 
> 
> Basically, what we have here is a standard full-range gain stage into a cathode follower circuit that then leads to the tone stack. The cathode follower changes the high impedance signal into a lower impedance signal that is strong enough to drive the tone stack with minimal signal degradation. This is why the cathode follower is used here. The tone stack itself is a bit odd in construction as you can see, and rumor has it that the Vox designers simply stole this circuit intact from a Gibson amp design. The bass and treble controls are EXTREMELY interactive. This is to say that adjusting the “treble” control affects the sweep of the “bass” control and vice versa. You’ve really got to play with the controls a bit to get the hang of how they operate, but they do sound great together!
> 
> To install this new circuit, we need to:
> 
> 1.	Physically mount the bottom of the module to the existing bolt underneath the center of the chassis between said chassis and the slider board.
> 2.	As the module contains a tube, we need to connect it’s heater into the existing heater string.
> 3.	Connect the module’s B+ into the existing HT rail at the junction of voltage dropping resistors R10 and R11.
> 4.	Connect the module’s ground wire to the grounding tab next to V1.
> 5.	Insert the module into the bright channel’s signal path between the wiper of the volume pot and R9, which carries the final signal to the phase inverter.
> 6.	Add a 100pf “Bright Cap” to the aforementioned volume pot.
> 7.	Drill a hole into the chassis for the module’s support screw.
> 
> Here’s a schematic I’ve doctored showing all of these insertion points:
> 
> 
> 
> 
> 
> 
> Here’s a picture looking at the back of the amp that shows all of the insertion points for the grounding wire, the B+ wire, and where the module’s heater wires will be attached.
> 
> 
> 
> 
> 
> 
> Now, let’s do it!
> 
> First, I soldered the B+ wire and the heaters to their respective terminals. Note that the heater wires on the module are blue and yellow, which match the color code of the amp’s existing heater string. Thus we simply solder the blue wire to pins 4/5 on V2, and the yellow wire goes to pin 9. Here’s what this step looks like completed:
> 
> 
> 
> 
> 
> 
> Note that I’ve dressed the heater wires out and away from the tag board in order to keep induced noise from the heater string to a minimum.
> 
> Now we can attach the black ground wire to the aforementioned grounding tab at V1. I ran this wire UNDER the tag board for cleanliness. You can see how it turned out here (note that there are now TWO black wires attached to the bottom solder lug underneath the nut):
> 
> 
> 
> 
> 
> 
> Now that the module has it’s B+, grounding and heater wiring straightened out, we can jump it into the signal path. As this module is inserted between R9 and the volume pot wiper, first we unsolder R9 from the brilliant channel volume pot. Here’s the pot pre-mod – it’s the one on the LEFT in this picture:
> 
> 
> 
> 
> 
> 
> In the following photo, I’ve connected the “hot” of the shielded cable going to the module’s pin 2 input grid to the volume pot wiper, and the cable’s ground connects to the pots’ grounding buss, as you can clearly see here:
> 
> 
> 
> 
> 
> 
> Also note that I’ve also installed the silver mica 100pf bright cap across the two “hot” terminals of the pot. Actually, the above picture is of the fully completed mod (output wire to R9 is on the right), but here's how I did it:
> 
> To connect the other shielded cable from the module’s “treble” pot directly to R9, I stripped away the end’s shield and covered it with heat shrink tubing for cleanliness and to quell any accidental shorts due to exposed shielding wires. Also note that I’ve slid the final piece of shrink wrap over R9’s lead to insulate the final joint in the next step:
> 
> 
> 
> 
> 
> 
> Finally, here’s the joint with it’s shrink wrap fastened:
> 
> 
> 
> 
> 
> 
> Now, we simply drill (and counter-sink) the hole for the top mounting screw and attach it. Here’s the completed modification:
> 
> 
> 
> 
> 
> 
> Normally, the next step would be to rout out the rectangular hole in the back panel for control access. However, since this is a vintage amp we didn’t want to do any permanent alterations outside of drilling the one tiny hole for the top screw (which is covered by the back panel anyway). This client has ordered a reproduction cabinet and back panel in a vintage correct “fawn” color, and it already has the cutout in the back panel done for us. This way, we can keep the original cabinet fully intact and at the same time preserve it from further wear and tear. He’s brining it with him when he picks up the amp, and I'll post pics once I get the amplifier fully re-assembled.
> 
> This amp sounds AMAZING, and the addition of this module really made it’s “Brilliant” channel sing. I hope this has helped you understand both what’s going on in the circuit as well as how to physically mount the module. As you can see, it’s not TOO hard, and the amp really roars now.
> 
> Cheers, folks, and as usual feel free to post if you have any questions, comments or rants!
> 
> -Lane
> 
> P.S. - Here's a GREAT reference link for all of you Voxophiles out there!
> 
> http://www.blueguitar.org/new/articles/other/topboost.pdf




GREAT POST LANE.

Now You need to get one of these bad boys.

 TWIN


----------



## Lane Sparber

New pix in the FB workbench section...for those who care about such things (I have been keeping myself pretty busy, thank heavens!). The new pics include a 1974 HiWatt DR 103 repair, a 1959 restoration, and some guitar repairs, among other things. Check it out if you like! 

Lane's Workshop | Facebook

-Lane


----------



## Lane Sparber

During my day job today, I was asked by a couple of touring techs for notes on how to bias their bands' amps. This band tours with Fender and Orange amps, and they were asking primarily about the Fenders. Here's the quick primer I sent them on biasing. I post it here in the hopes that others may read it and possibly better understand the process. Here's my missive (with some minor alterations for Forum use). Feel free to comment, lambast or flame me at will! 

BIASING: A quick tutorial.

SAFETY FIRST:

These amps contain voltages that can KILL you. Dead. They can also store this lethal charge for MONTHS after they’ve been unplugged. You MUST practice proper safety procedures when working on an amp. If you don’t know how to drain the filter caps, please ask me for that info BEFORE doing any serious work. Also, when working on a live amp, take off all jewelry/rings beforehand and ALWAYS keep one arm behind your back if the amp is live. This will nullify the chance that any current will arc across your arms and through your heart when working. You can still shock your arm by touching two points with a voltage/current potential across them, and this will hurt like hell, but shouldn’t KILL you.

If I haven’t scared you off, then let’s get to work. If you like, you can print and cut out the following to tape to the inside of your workbox. 

To bias any generic, class A/B push pull fixed bias output stage with common tools, we need these items:

-A Bias Probe
-Two Multi Meters
-A full set of PLASTIC HANDLED jeweler’s screwdrivers. Non-conductive handles are the key here to avoid accidental shock.
-A MATCHED SET of power tubes.

To bias the amp, we need to know:

-The LOADED plate voltage (with all tubes in the amp)
-The maximum plate dissipation (in watts) of the power tubes used by the amp we’re working with.

To bias a Fender amp with 6L6GCs:

1.	Remove the chassis from the cabinet (or head box) and prop it up on a sturdy surface. LEAVE THE SPEAKERS CONNECTED FOR THE ENTIRE PROCESS!!!

2.	Remove the old power tubes and leave the sockets empty for now.

3.	Turn all knobs to zero.

4.	Clip the black lead of one of your meters to the chassis. This will be the meter that measures the bias voltage and the loaded plate voltage, so set it to read volts DC.

5.	Power the amp on and CAREFULLY measure the voltage at PIN 5 of any power tube socket. It should be a negative number between 30vdc and 50vdc. Turn the bias pot all the way UP so that you get the MAXIMUM negative voltage there. This will bias the tubes VERY coldly upon startup and insure that they do not red-plate out of the gate.

6.	Install the new, MATCHED power tubes (one of them obviously goes into the bias probe and THEN into the tube socket). Hook the bias probe up to the second meter. If your bias probe reads voltage, set the meter to read “Millivolts” or “mV”. If the bias probe reads current (or amperage), set that meter to read “milliamps,” or “mA.” 

7.	Turn the amp’s power and standby switches ON, and let it warm up for at least two minutes. You should now also have a reading on the bias probe’s meter of how much current that tube is drawing in mV or mA, depending on the probe type.

8.	Once the amp has warmed up, place the red lead of the voltage meter on PIN 3 of any power tube socket. You should get a voltage (depending on the amp) of anywhere between 420vdc-500vdc. Write this number down.

9.	To calculate the bias, we take the maximum dissipation rating for the tube, divide it by the plate voltage, and then multiply it by the percent dissipation we’re after. Most techs aim for 65% dissipation, which is a nice, safe number. NEVER EVER go above 70%. Finally we add 2ma for screen current, because almost all bias probes read the current at the power tubes’ cathodes (PIN 8), and the power tubes’ screens eat some of that current up. So, let’s assume we get 460vdc at pin 3 of the power tubes, which as we know are 6L6GCs. For a 6L6GC, the maximum dissipation in fixed bias class A/B operation is 30 watts. The calculation would be:

30watts/460vdc on the plate*.65% dissipation plus .002 (2 milliamps of screen current). 

To simplify:

30/460*.65+.002=0.04539130434ma…or 45ma, rounded off. Adjust your bias pot until the meter on the bias probe displays 45ma. It’s actually pretty easy.

10.	Once you’ve adjusted your bias initially, re-check your plate voltage at PIN 3 of the power tubes. I bet it’s changed, as it always does when you make significant bias adjustments. Simply repeat steps 8 and 9 one more time. Things should even out after that. If not, repeat steps 8 and 9 yet again.

11.	Leave the amp on for at least 15 more minutes. The amp will settle in after that time and the numbers might drift a bit. If they have, repeat steps 8 and 9 yet again. If the bias holds steady for another few minutes, you’re done! Remove the bias probe and re-assemble the amp.

12.	If you adjusted the amp with the voltage regulator in place and use it from now on, your bias (and the amp’s circuit in general) should remain stable, all things being equal.

How does this process change for for an EL34 tube (like the ones in the ORANGE amps you’re touring with)? Well, the maximum dissipation rating is 25 watts instead of 30 and we add 5ma for screen current instead of 2ma, so our above equation would change accordingly.

That’s biasing in a nutshell. Make sure you FULLY understand these instructions before proceeding. I assume NO responsibility or liability should you not heed these instructions fully and injure yourself. PLEASE be careful out there!

Finally, to bias your “The Twin” amps, just follow the instructions in the manual, which you can find here:

http://support.fender.com/manuals/guitar_amplifiers/94_Twin_Amp_manual.pdf

If you want to do this super-duper accurate procedure I outline above on THESE amps, you CAN do it, but the process is a bit different. Hit me up and I’ll walk you through it.

All the best!

-Lane


----------



## cylon185

Awesome again.


----------



## JTyson

Great stuff, I appreciate you posting this, I know it took quite a bit of time


----------



## Lane Sparber

Interesting new developments...after talking with the makers of the Top Boost unit I installed in that Vox, they linked to my blog on their site. Check it out here:

Vintage Pedal Workshop » AC30 Top Boost Unit

I am also currently accepting ideas for future blogs...what would you guys like to see? Hit me up!

-Lane

P.S. - The wife says any new blog ideas should not be too time consuming! 

-Lane


----------



## MajorNut1967

Lane,

Excellent post, presented well and with great info. I'm glad the forum has a Gentleman like you to help us with the tube amp questions! Thank you!

MajorNut1967


----------



## TwinACStacks

Jeez Major. You should at least buy him dinner first.

 TWIN


----------



## MajorNut1967

TwinACStacks said:


> Jeez Major. You should at least buy him dinner first.
> 
> TWIN



why you're the one that's going to be the tossed salad! what took you so long to bite?


----------



## Joey Voltage

MajorNut1967 said:


> why you're the one that's going to be the tossed salad! what took you so long to bite?


 I think I'd rather be the salad than the one tossing it


----------



## MajorNut1967

Joey Voltage said:


> I think I'd rather be the salad than the one tossing it



Do you know of anything besides the Salad that gets tossed? And I don't want to hear any of that Metro-sexual BS that undoubtedly some of the girly mans will say! LOL


----------



## TwinACStacks

majornut1967 said:


> why you're the one that's going to be the tossed salad! What took you so long to bite?



:d:d:d:d twin


----------



## TwinACStacks

???? I can't live without emoticons.

TWIN


----------



## Lane Sparber

*VOX Repair - The CODA*

Hey, all!

Sorry I've been less active here...I've been REALLY busy!

In the meantime until my schedule clears up, please enjoy some quick shots of the completed Vox repair I detail in the above posts. I REALLY like the new repro "Fawn" colored cabinet that this client chose! 

The front:






The back (note the cutout for the top boost module!):






Finally, the control panel:






Working on an amp like this was a once in a lifetime experience, and I'm glad I got the privilege. I don't take it lightly!!

-Lane


----------



## MM54

Very nice 

Also, where did you get your spools of wire?


----------



## Lane Sparber

MM54 said:


> Also, where did you get your spools of wire?



I think all of the colored 600v wire spools are from AES (tubesandmore.com) and the cloth braided wire came from Stew-Mac.

-Lane


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## MM54

22 AWG? Maybe my mind's slipping but something made me think 20 was the common 'recommendation' for tube amps. Nonetheless, COOL! I didn't know they had wire by the spool, and pretty cheap too. I'll have to stock up some time


----------



## MajorNut1967

MM54 said:


> 22 AWG? Maybe my mind's slipping but something made me think 20 was the common 'recommendation' for tube amps. Nonetheless, COOL! I didn't know they had wire by the spool, and pretty cheap too. I'll have to stock up some time



Either is fine for signal and B+, but not for Heaters. 22ga wire will carry 1 amp fine; 20ga will carry 1.5 amps.


----------



## MM54

MajorNut1967 said:


> Either is fine for signal and B+, but not for Heaters. 22ga wire will carry 1 amp fine; 20ga will carry 1.5 amps.



That makes two things I learned today! (The other is that small earthquakes are trippy)

Thanks Major


----------



## David Davies

Hi Lane, Thanks for posting on how to fit a top boost on and ac30. I do have a question on this - Can you help? I really liked your pictures. It looks as if you were working on a westrex chassis. You mention attaching the shield on the signal line to the negative rail near the volume pot. Is the other end of the sheilding attached to anything on the unit? I also noticed the doubles resistors - are these to adjust for high originals? Thanks again David


----------



## Lane Sparber

David Davies said:


> Hi Lane, Thanks for posting on how to fit a top boost on and ac30. I do have a question on this - Can you help? I really liked your pictures. It looks as if you were working on a westrex chassis. You mention attaching the shield on the signal line to the negative rail near the volume pot. Is the other end of the sheilding attached to anything on the unit?



Hey, David! Welcome!

Yes, the shield on that cable is attached at the negative rail near the volume pot ONLY. The other end is heat-shrinked over and doesn't attach to anything in order to avoid possible ground loops. You are correct!



David Davies said:


> I also noticed the doubles resistors - are these to adjust for high originals? Thanks again David



Yes. It seems that all of the original 220k resistors had failed completely open. Later on, I broke down and removed all of the dead original resistors and the "V" resistors strapped over them. I put in fresh 220ks flat against the board just like the originals. Once again, you are correct.



-Lane


----------



## MM54

Lane Sparber said:


> ...It seems that all of the original 220k resistors had failed completely open...




That's just weird


----------



## Lane Sparber

MM54 said:


> That's just weird



Kinda...I've seen it before once or twice where one value in an amp had drifted completely while the others were more or less on spec. Bad batch, I guess.

-Lane


----------



## jcmjmp

MajorNut1967 said:


> Either is fine for signal and B+, but not for Heaters. 22ga wire will carry 1 amp fine; 20ga will carry 1.5 amps.



For the heaters, its not just the amps... its also the voltage, no?

Where did you get that 1.5a rating and at what voltage is that?


----------



## chadjwil

The current rating of wire is a standardized thing based on its diameter and whether or not it is solid or stranded. You can do some math and figure it out, but it's easier to look it up in a reference book.

The only real concern for voltage is that the higher the voltage the larger the electromagnetic field surrounduing the wire is, which could lead to interference and "cross talk"...basically inducing the signal from one wire onto another wire if it's physically close enough. AC is worse about this than DC, and high frequency AC is the worst, although we're really talking about radio frequency...like megahertz type stuff, not really something we worry about too much in our amps. If it were that big of a deal in Marshalls you would see more shielded wires inside them.


----------



## Lane Sparber

chadjwil said:


> If it were that big of a deal in Marshalls you would see more shielded wires inside them.



While that was an EXCELLENT post for the most part, Chad, I must say that I can't agree 100% with this statement. IMHO, there were a lot of times when Marshall SHOULD have used shielded wire and DIDN'T. By way of example, every 2203/2204 that comes into my shop gets shielded wire installed to the grids of V1a and V1b. You'd be AMAZED at how much quieter those amps get if you do this...not to mention that it also dramatically lessens (or removes _entirely_) the oscillating you can get on those amps if you dime the Presence, Treble, and both volumes all at once.

-Lane


----------



## chadjwil

Oh, without a doubt Lane. That's why you sometimes can hear a radio station through your speakers. Adding a little shielding is definitely a worthwhile upgrade to any tube amp...I was just pointing out that the freqs going through our amps aren't big problems, unlike any RF reciever or transmitter. I worked on a GPS unit once that we had to separate wires by a foot before it would even begin to work! That's bad RF interference. The unit itself was only about 5 inches by 10 inches, it was a mock up pre-production dillyo but it illustrates how bad E-fields can be in high frequency wires.

Glad you checked me on that one Lane, very worthwhile info for anyone who has the courage and desire to make a noticeable improvement to their rig!


----------



## MajorNut1967

lol


----------



## chadjwil

Oh, I see. Well hopefully someone will find that info as useful as you find it amusing.

I told you, it's not hard to get over on me. Enjoy


----------



## Lane Sparber

*Rangemaster Kit Assembly*

Tony Iommi. Brian May. Marc Bolan of “T.Rex” fame. What do they all have in common besides incredible tone? Well, they all were users of a semi-obsure unit called the “Dallas Rangemaster." The Rangemaster had a unique treble booster circuit utilizing a single germanim transistor. Rumor has it that Eric Clapton also used one of these devices on the “Bluesbreaker” album, however to my knowledge this has never been verified.

I had always wanted a Rangemaster, but the originals are extremely rare and pricy. In addition, most modern copies are put into pedal format and most folks add all sorts of whistles and bells to the original circuit. I simply wasn’t interested in a modded Rangemaster in a pedal – I wanted as close to the real thing as I could get. So, when looking at V.P.W.’s website one day, I came across _this_:

Vintage Pedal Workshop » RANGEMASTER KIT

…and it was PERFECT! It is a clone of the original stand-alone unit right down to the front panel graphics and hammered metal finish. The ONLY modification in this kit to the original circuit was the conversion of the “On/Off” switch to true bypass. IMHO this is a welcome improvement. It also uses an American made replica of the OC-75 transistor used in many of the originals 

I had to have one. Just HAD to! In this blog entry, I will share my experience building this iconic little monster.

Here’s how the kit is packaged:






…and here is the hand-drawn wiring diagram that accompanies the instruction packet that comes with the kit:






If you’re following along (or want to build one yourself), you might want to print out that diagram and refer to it as we go. If you’re just along for the ride, enjoy!

The first order of business was to assemble the tag strip as much as possible before installing it into the chassis. If you look closely, you’ll see that it’s possible to assemble and solder the ENTIRE tag strip prior to installation – with the sole exception of the far left tab. This is because one of the battery’s leads will connect there, and we need to run those wires through the chassis later on in the process.

I found it easiest for assembly to tape the tag strip vertically to my workbench like so:






Having secured the tag strip, I began bending leads and installing the components. This is the most critical and involved step of the entire build, and so I took EXTRA care to make sure that all components were in the right place and that the work was neat. Due to the nature of tag strip construction, making changes after the fact is a real pain, and I didn’t want to have to disassemble the whole thing again later. I tried my best to make sure to get it right the FIRST time. Here’s a picture of the 3 resistors, some of the wires and one of the caps installed:






Note that nothing is actually soldered yet. This is important. I did not solder ANYTHING on this strip until all components were present and all components triple checked. Here are two photos of the completed tag strip just prior to final soldering and lead trimming:











At this point, I checked each nexus point on the tag strip thoroughly to make sure that nothing was accidentally in the wrong place. I actually checked off each connection at each lug on my instruction sheet as I wanted to make sure it all added up. Finally, it was ready for soldering and installation, which looked like this when completed:






Next step? Installing the 9v battery connector so that I could solder that last joint on the tag strip:






I then moved to prepping the “On/Off” switch, because there were also some connections there that needed to be taken care of prior to installation. First I dealt with the shielded output wire, which gets it’s braid soldered to the switch body and the hot wire soldered to the middle lug:






Flipping the switch over, I made the final pre-connections as per the diagram:






At last, all other components could now be mounted and the final wiring tasks performed. The faceplate is also held in place by these components, so that was also installed at this point.






Here’s a top shot of the chassis at this point in the build:






I started the last few steps by wiring up the front panel jack as per the diagram:






Now, the 4n7 capacitor from the tag board needs it’s remaining lead extended in order to make it to the switch. Here, I’ve soldered the extension in place before slipping the insulation provided with the kit over the joint:






Finally, I wired up the rest of the switch and the pot, thus completing all internal connections. Here are some photos of the completed interior:











After installing the 1/4" plug onto the output cable, I needed to check the transistor’s bias voltage at the collector as per the written instructions. These instructions advised that the bias voltage could vary based on battery health and ambient temperature conditions. The recommended voltage was -7vdc, plus or minus 1 volt. As a cable needs to be inserted into the font panel jack to power up the unit, I did so at this time.






Here’s my voltage reading:






Almost dead-on perfect. I then plugged the unit into a 2203 and rocked out for a while to test it out. It sounded…incredible. It provided clarity, definition, and a nice ringing tone that hadn’t been there before. I was quite unexpectedly knocked out by what I heard. Time to box it up! Here I have installed the cover and the supplied rubber feet:






Here is the completed build:






I hope that you have found my exploits here informative and entertaining. I'd like to point out that the Rangemaster was _not _meant to be used as a pedal; it was meant to be switched on and LEFT on at all times. I can see why. The true bypass modification was admittedly a nice touch, but I doubt I’ll be using it much. This little beast has earned a permanent place atop any amp I play through.

Until next time, cheers, folks…and thanks for reading!

-Lane


----------



## MajorNut1967

*Re: Rangemaster Kit Assembly*



Lane Sparber said:


> Tony Iommi. Brian May. Marc Bolan of “T.Rex” fame. What do they all have in common besides incredible tone? Well, they all were users of a semi-obsure unit called the “Dallas Rangemaster." The Rangemaster had a unique treble booster circuit utilizing a single germanim transistor. Rumor has it that Eric Clapton also used one of these devices on the “Bluesbreaker” album, however to my knowledge this has never been verified.
> 
> I had always wanted a Rangemaster, but the originals are extremely rare and pricy. In addition, most modern copies are put into pedal format and most folks add all sorts of whistles and bells to the original circuit. I simply wasn’t interested in a modded Rangemaster in a pedal – I wanted as close to the real thing as I could get. So, when looking at V.P.W.’s website one day, I came across _this_:



First of all the range master is not a semi-obscure device, it's only obscure to you Americans. It was as widely used as the pro-co rat or the bigmuff was in the States, as the range master was in the UK and Europe since the mid-60s. The fact is the Yanks took forever to figure out what was creating that sound.


----------



## MajorNut1967

can we have some sound samples please?


----------



## Lane Sparber

*Re: Rangemaster Kit Assembly*



MajorNut1967 said:


> First of all the range master is not a semi-obscure device, it's only obscure to you Americans. It was as widely used as the pro-co rat or the bigmuff was in the States, as the range master was in the UK and Europe since the mid-60s. The fact is the Yanks took forever to figure out what was creating that sound.



Stupid Americans! . I will try to get some decent sound clips. 

-Lane


----------



## MM54

Very nice, I like terminal strips for some reason, they make circuits look so small and efficient 

Can't wait for some clips


----------



## MajorNut1967

MM54 said:


> Very nice, I like terminal strips for some reason, they make circuits look so small and efficient
> 
> Can't wait for some clips



Isn't that choice to do it the old way!


----------



## TwinACStacks

*Re: Rangemaster Kit Assembly*



MajorNut1967 said:


> First of all the range master is not a semi-obscure device, it's only obscure to you Americans. It was as widely used as the pro-co rat or the bigmuff was in the States, as the range master was in the UK and Europe since the mid-60s. The fact is the Yanks took forever to figure out what was creating that sound.



 How is it You Brit Blokes always have the NEWEST stuff?

All Us Scots ever do Is make Whiskey, Fight, Breed animals and Fuck our Womins.

On second thought that ain't half-bad.

Major, be a good Laddie and toss me that Caber over there. Yeah, the BIG one....

 TWIN


----------



## MajorNut1967

*Re: Rangemaster Kit Assembly*



TwinACStacks said:


> How is it You Brit Blokes always have the NEWEST stuff?
> 
> All Us Scots ever do Is make Whiskey, Fight, Breed animals and Fuck our Womins.
> 
> On second thought that ain't half-bad.
> 
> Major, be a good Laddie and toss me that Caber over there. Yeah, the BIG one....
> 
> TWIN



Roger that mate! What's a Caber? LOL Actually we have a Highland games down in Turakina about 5hrs from Auckland.


----------



## SigurdTheGreat

Nice one, Lane!

As it reportedly worked like a charm with a 2203, it got added to my project waiting list. Indeed, I had been searching for an OD for my JMP 2203, but I think I'll make one of those instead.


----------



## Lane Sparber

SigurdTheGreat said:


> Nice one, Lane!
> 
> As it reportedly worked like a charm with a 2203, it got added to my project waiting list. Indeed, I had been searching for an OD for my JMP 2203, but I think I'll make one of those instead.



I highly recommend it. I love mine! 

-Lane


----------



## TwinACStacks

Lane Sparber said:


> I highly recommend it. I love mine!
> 
> -Lane



Lane, Did you order yours from Britain on that website?

 TWIN


----------



## Lane Sparber

TwinACStacks said:


> Lane, Did you order yours from Britain on that website?
> 
> TWIN



Yeah, the one I linked to. I believe they also have one up on the US version of eBay. They're the same company that built that Top Boost module my other client bought. That's how I found this kit, actually! 

-Lane


----------



## Lane Sparber

Hello, Marshall Forum family!

I am back _temporarily_ to deliver on a promise made to certain MF members on Facebook. Some of you wanted a blog about an amp repair I was planning to perform on a piece that I literally discovered on the street one afternoon.

I was walking home in a light drizzling rain when I saw that one of my neighbors had thrown out a slew of stereo gear. Among that gear was a Harman-Kardon “Allegro” integrated tube amp. This is a MONO 15w class AB amplifier that uses two EL84 tubes in it’s cathode biased output section. It’s the little brother to the H-K “Ballad” stereo amp in my listening room! Well, I don’t usually pride myself on being a dumpster-diver, but I literally couldn’t help myself. I swiped this little gem later that night under cover of darkness. I brought it home eagerly, but as I had a pile of amps to work on and this was a personal project, it had to wait patiently until I had the time. 

Well, the wife took both kids out yesterday for errands and I had an empty shop - _and _I had the afternoon to myself. I was SUPPOSED to relax and take it easy, but my soldering iron literally called me into the workshop to finish this little project while I can - before I’m hit with the next incoming round of broken amps. Thus, I eagerly made my way downstairs to see what this diminutive monster had in store for me.

I wanted to establish a single over-arcing ground rule for this repair to make it interesting: I was limiting my budget to $50.00. As this was literally a found item, I didn’t want to sink a lot of money into it, and it would be a good exercise in economy and good decision-making, as this also kept me from going nuts and modding the SNOT out of it! 

The night I…um…”rescued” this amp, I took it apart to make a quick part order. To my dismay, all of the original Mullard tubes were shattered and/or not working, so that was the first hurdle. I had used-but-good (mostly NOS) tubes in my bin that would work, but the sticking point was the EZ80 9-pin rectifier tube. That’s a fairly rare tube, so I needed to buy one. Damn. No one I checked with had one, so it was off to eBay land! $14.99 + $5.50 for shipping. Total so far? $20.49

It obviously needed a re-cap, as all of the electrolytics were original, and in a single “3 in 1” cardboard tube. It had clearly failed. There are two options in this instance: Take the cap apart and install new radial caps INSIDE the old tube thus preserving the “look” of the amp’s interior (this approach is favored by many old-time radio enthusiasts), or just use discrete caps soldered directly onto the board. I chose the latter. There were only two filter caps plus the cathode bypass cap on the power tubes. As there was VERY little space on the board to fit these caps, I chose radials, and I also had to pay close attention to the physical size of the new caps I was going to order so that they would fit and play nicely with the other components fighting for the same real estate. 

It’s worthwhile at this point to note that the first filter cap after the rectifier tube was a 40uf/375v cap. Now, the most common and closest values to the original component (in radial caps) nowadays are 33uf and 47uf. I went with the 33uf. Why go with the LOWER capacitance when we all know that -to a point at least- more capacitance equals a tighter, more focused sound; something ESPECIALLY desirable in a high-fi amp? Because a quick check of the spec sheet for the EZ80 lists 50uf as the MAXIMUM capacitance value that it wants to “see” after it. The 47uf cap could, with it’s standard 20% tolerance, go as high as 56uf. That’s obviously over the limit for this rectifier tube. Would it still work perfectly? Most likely. Did I want to risk it with my new twenty-dollar rectifier tube? Most definitely I did NOT. Hence, I went with the 33uf.

Finally, the two resistors in the power tubes’ “balance” circuit had burned themselves literally in half. Something catastrophic had happened inside this chassis! I didn’t have those 330 ohm 1 watt resistors in stock either.

In addition to all of that, this amp also needed a new fuse and pilot light - both of which I thankfully had PLENTY of in stock. However, it also had two molded paper coupling caps, which DID have to go, as paper caps don’t age or hold their value well. Thus, my Mouser order contained 3 electrolytic radial capacitors, two Sprague “Orange Drop” coupling caps, and the two new power tube balance resistors. The total cost at Mouser plus shipping came to $17.91

Parts total: $20.49 + $17.91 = $38.40. Not bad. I even had some “padding” there for later just in case I needed anything else.

Now on to the exciting stuff…the actual repair. Here’s what I found when I pulled the lid off of the chassis and removed the old tubes and broken glass:






Pretty clean, all things considered! Note the area to the middle left of the drawing where the multi section capacitor’s black/red/yellow/green wires join the board. This is the entirety of the space I had to mount all 3 new electrolytic caps!

Here’s a close-up of the old electrolytic cap can. Note the mis-shapen wax bulge on the right side of the cap where the leads emerge – this thing had DEFINITELY joined the choir invisible!






Here are the two fried power tube balance resistors:






Finally, here are the two ancient paper coupling caps that had to go:











In addition, when that electrolytic cap can fried, it literally melted, sending molten wax down the chassis and into the volume pot, which also contains the power switch. This component is common in old hi-fi equipment like this – basically, when you turn the volume all the way down, a little extra pressure will engage the power switch and shut the amp off. The wax had rendered this pot absolutely immobile (unless I heated the shaft with a soldering iron). I was going to have to perform the INCREDIBLY risky job of removing this delicate component, dismantling it, and manually removing the wax. Here it is disassembled and ready for repair:






I removed the wax by applying heat indirectly with my Zippo and quickly removing the molten wax with Q-Tips. This had to be done separately on the shaft/wiper assembly, carbon ring, and body of the pot. It took a while, but when I was done it turned smoothly and tested fine on the meter. I then reinstalled it into the amp.

Next up I installed the new fuse, pilot light, and 330 ohm balance resistors. This brought me to the stickiest problem - figuring out the best way to mount the new electrolytic caps. After entertaining several mounting options, I decided to mount one filter cap vertically and one filter cap horizontally, securing them both with hot glue. This way, they would take up the least possible amount of real estate and at the same time maintain maximum distance from the sensitive preamp circuitry less than an inch away! Here are two angles of the finished, mounted caps:











Now, you might have noticed that there is almost NO space left to mount the cathode bypass cap, which theoretically goes right next to those caps. My solution to this problem was to “cheat!” I mounted it to the other side of the circuit board…underneath the other components:






Next, those two paper coupling caps had to go. Here are the new Orange Drop caps installed in their new homes:











At this stage of the repair, I was ready to form the electrolytics on the Variac and test this amp out, but instead I was provided with yet another challenge. This amp, like many older radios/stereos of the era was equipped with a “safety” feature wherein the power cord was riveted to the outer chassis, so that when the cover was removed, the power cable came with it. Thus, you could not physically power the amp on when the cover was removed. Well, this just wouldn’t do, so I needed to come up with a workaround. The solution? Fortunately the designers of this particular amp saw fit to include an auxiliary outlet on the back of the chassis. EUREKA! I could feed the power INTO this outlet and use it for the exact opposite of it’s intended purpose! This way, I could get power into the amp while it was disassembled. I stripped the insulation from an old zip cord power cable I had and tinned the ends with solder to avoid stray strands of wire shorting anything out. I fed them right into the auxiliary outlet and plugged the other end into my Variac. Worked like a charm:






WARNING!! The above step and it’s solution are VERY dangerous. Do NOT, I repeat NOT try this at home unless you have a thorough knowledge of electrical theory and safety procedures. Trained professionals ONLY. 

Once fired up, to my amazement, it ACTUALLY WORKED! Without it’s outer covers, it was a bit noisy, but it still sang and chimed and sounded fantastic. All voltages checked out too! Sometimes, you just get lucky.

It was time for cleanup. I didn’t feel like cutting the metal straps and removing the old multi section capacitor, so I just clipped the bare leads and cable-tied the wires to the cap’s body. Now it was totally removed from the circuit and out of the way. It won’t be hurting anyone anymore. 






Here’s a master shot of the finished underside of the chassis:






Next, here is the amp all fired up for testing. Note the trusty iPod feeding it on the left side of the picture:






All ready to rock!






I spent the entirety of the remaining afternoon CRANKING Beatles’ mono mixes through this beast, and it was an incredible listening experience, to say the least. Tube audio amps, like their guitar counterparts, just sound better. If you ever get the chance, try it yourself and hear the difference!

Now I just have to decide what to do with this amp. Any ideas? Any takers? 

As a quick aside, I _am_ still in my recuperative phase. I need this time to heal and get my head together, and already I _do_ feel much better. I WILL be back eventually, but for now I’m just not ready to come back on a more permanent basis. 

Thank you all SO MUCH for your kind words and concern. I assure you that these sentiments mean the WORLD to me, and have aided in my recovery to an un-measureable degree.

Cheers, and sayonara again for now!

Most importantly:

HAPPY HALLOWEEN!

-Lane


----------



## cylon185

Great stuff as always Lane


----------



## thrawn86

Good read, Lane. Please take your time and heal properly. One of the worst things you can do is rush your recovery since you feel better, and end up lengthening the process. We miss you bro, but we'll be waiting here.


----------



## Les Moore

I read somewhere that you left the forum. Can´t say how glad I am to see that that was wrong. Truly. 
Sad to read you´re ill. I think you rock. Get well soon


----------



## Lane Sparber

Les Moore said:


> I read somewhere that you left the forum. Can´t say how glad I am to see that that was wrong. Truly.
> Sad to read you´re ill. I think you rock. Get well soon



Thanks, Les.

I am in a MUCH better place now. I will probably be back - albeit on a more limited basis - some time after the new year. It seems that there are a few new guys handling things pretty well, and Joey's back (sort of) so you've all been in good hands. 

In the meantime, I just competed a wacky Marshall repair that I'm thinking of doing a new blog about, so maybe that will be up in the next week or two. I consider writing these blogs therapeutic...don't know what THAT says about me! 

Cheers, and thanks for the concern, everyone! 

-Lane


----------



## TwinACStacks

I do miss you, better-looking Little Bro. Say Hi to Mom for me.

 TWIN


----------



## Lane Sparber

Hello again, faithful blog readers!

Today’s offering is about a 1974 Marshall model 1959 that recently came into my shop. The owner had bought this in a lot with two other amps for the princely sum of 500 bucks. That’s right, he got this vintage Marshall head for about $166 dollars. Why can’t this stuff happen to me?!?

Anyway, he brought it into my shop for a checkup, as it had been worked on, and he wanted to make sure it was bone stock and in good health. This client is in a major touring band and runs a busy recording studio on the side, so we needed to make this amp as “bullet-proof” as possible. The first thing I noticed when plugged in was that the amp was VERY noisy for a ‘59, and, well, it just didn’t sound right to me. It also distorted around “2” on both volumes, and anyone who has EVER been lucky enough to own a 1959 (my personal favorite Marshall model, for those who care), that just ain’t right. Externally, it also had one mismatched speaker jack that the client had tried out on his own, and he found that this jack didn’t seem to do anything at all. Curious. It also had all of it’s original DALY filter caps, which I initially thought was the cause of all of that noise. Those caps’ days were numbered.

Upon disassembling the amp, I noticed that the power transformer had been replaced at some point with another Dagnall. I STILL can’t find much out about this PT, and, regrettably I didn’t take a clear pic of it. It was MASSIVE, and new holes had to be drilled in the chassis to accommodate it. It had a sticker on it that identified it as a “T3556” model, but almost NOTHING about it is on the web. To complicate matters further, someone had written “Fender” on it with a non-existent part number. I found ONE picture of a “Dagnall T3556” transformer on the internet, and it looked NOTHING like this one. This oddball tranny also featured cloth covered wire, which I’d NEVER seen on a Dagnall. Part of me thinks that someone just stuck that ID sticker on to fool people, although I could be wrong.

This amp had to be modded in SEVERAL ways to accommodate this transformer, because all of it’s secondaries were NOT spec for this amp:

1.	The heater winding had no center tap, meaning that a false center tap had to be created using two 100 ohm resistors from each leg to ground – Fender style. The original tech had installed these resistors RIGHT ACROSS THE V8 POWER TUBE SOCKET! BAD idea. THAT was what was creating a lot of that excess noise.

2.	The HT winding was 185-0-185 at a 120v input. That’s too high for vintage Marshall spec, which is about 175-0-175 The plate voltage on the tubes was over 500vdc. These tubes were the original GE 6550s, and they seemed to have taken it well, but it was time for a change.

3.	The bias supply winding was wound for roughly half of the voltage of an original Marshall 100w Dagnall PT. This winding needs to be 100vac for spec, and this one was 55v, so MAJOR mods to the bias supply had been done.

Thus we can see that this transformer was a poor choice for almost every conceivable reason. It needed to come out. I chose a Hammond replacement that was wound to vintage specs, with the addition of extra voltage taps on the primary for 220 and 240vac, respectively.

Finally, all of the 1 watt 10K B+ decoupling resistors had been replaced with ½ watt 15k resistors. Why was THIS done? I have no idea. Maybe it was to drop the preamp voltages back down to spec due to the higher B+ winding, but even so, 1 watt resistors _should _have been used.

So, here’s the laundry list of repairs for this amp:

1.	Install new power transformer and reverse all mods done to facilitate the incorrect one.

2.	Change the power section over to EL34 specs. This, IMHO, is CRUCIAL in a vintage non-master volume Marshall that shipped with 6550s; much more important and effective than doing this in a master volume Marshall from the same era. Why? Because non master volume amps get a significant amount of their distortion tone from over-driving the POWER section, and a 6550, to my ears, sounds MARKEDLY different from an EL34 in this respect. For true Marshall tone in an amp like this, it should be EL34s all the way!

3.	Replace the incorrect value and wattage B+ decopling resistors with the correct spec resistors.

4.	Replace the weird mis-matched speaker jack with a new, matching socket.

5. with a modern switch for drastically improved reliability.

6.	Disable the dangerous polarity selector switch.

7.	Fully re-cap the amp and bias it up.

Now, I try to give EVERYONE the benefit of the doubt, but over-all, the work done to this amp, while electrically sound, was amateurish at BEST. Sloppy, above-the-board mods, cold solder joints, and messy, carelessly arranged wiring abounded. Let’s take a look!

Here’s how the T3556 transformer was wired into the circuit. The wiring is sloppy and poorly done, but in this pic you CAN make out the cloth covered wire. Weird, no?






Here are the 100 ohm heater supply false center tap resistors wired RIGHT across the V8 power tube socket [shudder]:






The mis-matched modern style output jack:






Here’s the inside of the chassis, showing said mis-matched jack. HMMMMM….wonder why it didn’t work? IT WAS NEVER EVEN CONNECTED!






At some point, the original Erie 330uf cathode bypass cap on Channel 2 had failed. Here’s how it was dealt with:






Have a look at the bias supply on the right side of this shot. As previously stated, it had been modded to allow enough voltage out of that lower voltage bias tap to tame the 6550s, but the work was EMBARASSINGLY sloppy and the solder joints were ice cold. They actually broke apart as soon as I touched them. There's even solder dribble on the bias supply caps! Sigh. Also, on both sides of this pic you can see where all four of the 10k 1 watt B+ decoupling resistors have been replaced with ½ watt 15k resistors in the lazy, “above the board” splice’n’dice fashion. Lastly, note that the grid leak resistors to the power tubes (should be 150k for Marshall 6550 spec) are 82ks!






Here’s a closer look at that modded bias supply:






Below you can see the chassis after the removal of the old transformer. Note all of the extra holes that had to be drilled out for that old transformer. In the picture, I’ve already moved the rubber grommets on the left to the inner, original holes, and had yet to install the one on the right side (the T3556 had all of it’s wires exit on one side, as opposed to the more standard array using both sides of the transformer):






Unfortunately, the Hammond replacement transformer was STILL a little too narrow to fit into the vintage holes. It wasn’t a problem that some washers from the local hardware store couldn’t solve!






Here’s the underside of the chassis after mounting the new transformer, but before creating the wiring harness:






All wired up! Note at the bottom center of the picture that I heat-shrinked off and labeled the additional 220 and 240v primary taps (the blue and purple wires, respectively) just in case the owner decides to move to Europe at some point. 






Here’s how the V8 socket with turned out with cleaned up wiring – and no extra resistors!






With the new transformer installed and tested, it was time to move on to the re-cap and board repairs. I personally prefer to just un-bolt the pots rather than de-soldering them to get at the underside of the board. This pic should illustrate what I mean. Also, the jack and impedance selector were replaced at about this time. At the back of the pic you can see the new buss wiring I installed for the output jacks:






Here’s the back of the chassis showing the new output jack and impedance selector:






Now, this wouldn’t be a TRUE overblown and boring Lane’s blog entry without the gratuitous cap-forming shot, would it? You KNOW you want it!






Finally, we have the finished, cleaned up and re-capped board. Spot the differences! I know that those new blue Panasonic B+ decoupling resistors LOOK small, but they’re actually TWO watts and are rated for 600v! Cool!











Ready to rock!!






After re-building a good bit of this amp, it finally sounded LOUD, punchy, and did everything a healthy, vintage 1959 is supposed to do. All voltages checked out, and it sounded AWESOME. This was a hard one to give back to the owner. I especially felt a kinship with this amp because it’s the same vintage I am – a 1974 model!!

Thanks for reading this and sticking it out! I hope you were able to get something out of my experiences here and found at least some of it useful. It is, after all, why I do these.

Also, HAPPY THANKSGIVING! I am thankful for this forum, the fact that I was given my own little corner here to play in, and all of the wonderful techs and friends I’ve made here. Have a great holiday!

Until next time…and KEEP IT CRANKED!

-Lane


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## Kunnz

▀▄▀▄▀▄▀▄█▓▒░  1st Class, # 1  ░▒▓█▀▄▀▄▀▄▀▄▀


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## MM54

Excellent work as always, Lane 

I've used those little blue Panasonic resistors in a million different things, they're pretty awesome!


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## Lane Sparber

Hello again blog readers!

Today, I have another “by-request” offering for you. This entry isn’t so much a “how-to” missive like my others. Rather, this installment will document a basic repair/restoration on a fairly rare and VERY cool 1966 twin chassis Gretsch 6159 “Bass” Amp. This amp was one of many related models made by Valco for various distributors –Gretsch and Supro being two of the more famous imprints. Rumor has it that Jimmy Page recorded the first Led Zeppelin album in it’s entirety with a Supro cousin of this amp – how cool is that?! 






This is a REALLY cool little beast. Basically, it has 4 inputs – 2 bass inputs, an “Accordion” input (yes, you read that right…”Accordion”), and a guitar input. It features a tremolo circuit on the accordion/guitar channel as well. Here’s the schematic:






Check out that output section! What we have here is a pair of 6L6GC tubes in a cathode bias configuration. They’re biased fairly hotly at about 28 watts a tube according to the schematic, and my real-world measurements bore this out. To those who would ask me how I got that dissipation rating, here’s how - the info needed is all right there on the schematic:

30 volts at the power tubes’ cathodes divided by the 200 ohm cathode resistor=.15 amps or 150mA total draw (75mA per tube). So, we take 150mA multiplied by 370 volts (400 volts at the plate – 30v mean listed cathode voltage) = 55.5 total watts, or 27.75 watts per tube! That’s pretty close to the maximum dissipation rating of a 6L6GC at 30w, no?

When I received this amp, it was missing a power tube and needed a complete re-tube, had a two-conductor power cable and “death cap” installed, had a blown pilot light and, finally, it needed new caps. This is the story of how I approached the repair.

Here’s the control panel (I’ve already removed the lower chassis containing the power and output stages in this picture). Note that “Accordion” input! You can also see the Tolex at the bottom of the cabinet has all but detached around the base.






I wanted to tack that Tolex back down first and let it dry while I performed the repair, so I used my Luthier’s clamps (and a couple of industrial spring clamps) to fix the Tolex in place while the glue dried. In this picture, the glue and clamps are applied and we’re just waiting on the glue:





The upper chassis, which contains the preamp circuit, was REMARKABLY clean inside. Note the shielding plates soldered to the input jacks. The large white caps are the dried-up electrolytics that need replacing. Also, the soon-to-be-removed “death cap” is that HUGE ceramic cap on the bottom right side of the first picture.
















Here’s a top view of the lower chassis as I found it. Note the mounting hole punched into the chassis. This hole was originally intended for the rectifier tube in a previous iteration of this model. By ’66, when this amp was made, they’d already switched to solid state rectification. On this particular amp, however, they used an older lower chassis. A previous tech had simply cable-tied the main and preamp filter caps to these mounting holes. This was crude, but HIGHLY effective!











At the bottom of the above pic, that blue mini LCR was a dual cap that housed the preamp filters. The single Sprague Atom cap cable tied to it’s left in the pictures is the first main filter cap. Overall, this amp is criminally under-filtered for a bass amp. The highest filter cap value is just 20uf! As the owner liked the amp’s extremely spongy and uses it primarily for harmonica, I kept that scheme for the most part. I DID more than double the value of the screen filter cap to 47uf, however. This was because in the case of a modern bass being plugged into this amp, I wanted it to be able to hold together at a bit better at higher volumes without turning completely to mush!

The large silver filter cap for the power tubes’ screens (upper right in the above pic) was original, and needed to come out. I’ll never understand why some techs will replace SOME caps and not others. I just don’t get it. Can someone maybe enlighten me?

Another minor detail worthy of note is that there were no rubber grommets installed on this chassis where the cables passed through it. This is VERY bad, as over time the wires will chafe and the insulation then becomes compromised - leading to these wires possibly shorting to the chassis. So, I first installed new grommets:











Another idea I had was to make better use of that gaping rectifier hole in the chassis. I had a brand-new 16uf/16uf mini dual cap just like that old LCR in the photos, so I decided to mount this new cap to that hole vertically like in a Marshall. The other main filter cap I moved to the tag strip out of the way of everything else. Here’s how it turned out with the new caps and cleaned-up lead dress:






Here’s a close-up of the caps. Note what WAS that old Sprague Atom has become a black F&T 16uf cap mounted to the tag strip at the extreme left side of the image.






Here’s the top side of the chassis showing the new, vertically mounted dual filter cap:






Guess what’s coming up next?!? YOU GUESSED IT! CAP FORMING SHOT!!






Here are two quick shots of the upper chassis after cap replacement – the power cable has been replaced and it’s strain relief reinforced with hot glue, the death cap has been excised, and the old white electrolytic caps have been replaced with the silver Spragues:











Finally, here’s the lower chassis installed in situ:






To conclude, here’s a master shot of the back of the amp showing the cleaned up lead dress, re-glued Tolex, and new power cable:






So how did she sound? With a bass, it was surprisingly clear and loud, but not very “tight” or “punchy,” as was to be expected for the aforementioned reasons. With a guitar, though, this amp CAME ALIVE! Especially cranked, she exhibited a smooth, creamy distortion that had a tonal signature all it’s own. Think warm overdrive with a hint of sharper-edged breakup. This amp would be PERFECT for indie rockers, punks, and blues aficionados. 

Overall, this amp was a JOY to work on. You simply don’t see a lot of them around, and I was thrilled to finally dissect one and find out just how she “ticked.” Studying schematics are one thing, but actually having an example in front of you really brings it home. Being as how I was lucky enough to land one of these in my shop last month, I simply couldn’t pass up the rare opportunity to share the repair experience with my friends here on the Marshall Forum!

Thanks again for reading!

-Lane


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## Lowlife

nice read, you get to work on some pretty cool amps


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## MM54




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## Lane Sparber

*2203/2204 Squeal Remedy*

Does your 2203/2204 squeal like a banshee when the volumes, treble and presence controls are almost all the way up? Does it do this even with new tubes and caps? What I do in this situation is replace both grid wires on V1 with shielded cable and that usually clears it up. Here's how I do it (slightly modified from an earlier post - I just wanted it to be here in my sticky thread so it would be easier to find!): 

Remove ALL wires entirely going to pins 7 and 2 on V1 and set them aside.

The new shielded cable you're going to install from the "HI" input jack to pin 7 on V1 gets it's shield connected at the jack's ground. I use heat shrink on the other end to keep the shield from accidentally shorting anything out. Then, solder a 68k resistor between pin 7 and the hot of your shielded cable on that end. Keep the leads as short as possible. 

The other cable is even easier. It's ground gets soldered right at the volume pot. The other end gets the same heat shrink treatment and the hot goes right to pin 2 on V1. 

Keep both of these runs as short as possible and you should find that squeal greatly diminished, if not gone entirely. 

Good luck!

-Lane


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## Lane Sparber

One of (if not THE) most often asked question around most D.I.Y. forums is "How do I safely drain my filter caps?" Well, there are several methods you can use. Some of them are safe, and some...less so. I'll discuss a few of them here.

First, I'd like to dispel a myth which states that if you unplug the amp while it's powered up and leave the STANDBY on, it will discharge the filter caps on it's own. This is only PARTIALLY true. If your amp's high voltage rail does NOT have a "totem pole" stack (more on this below), it will only drain the caps until the tubes become cool enough to stop conducting, and this DOES leave a residual charge in the filter caps. Thus, you should ALWAYS check with your meter to make ABSOLUTELY sure that your caps are drained before doing ANY work on the amp.

So, continuing on, there are basically two ways that the filter caps can be wired into an amp's circuit. In some stages, two caps can be wired in SERIES (commonly referred to as a "totem-pole" stack) for a specific filtration section, while most stages just use one single cap on it's own. Keep in mind that both methods can be (and often ARE) used in the same amp. Some examples of amps with a totem pole stack would include almost all Fender Silverface and Blackface amps above 50 watts, and Marshall DSL and TSL amplifiers. Examples of amps WITHOUT a totem-pole stack would include other Marshall amps, such as the 1987, 2204, etc. The main difference between amps that use a totem-pole filter stack and those that don't for our purposes here is that amps incorporating a totem-pole stack into their design will, in theory, COMPLETELY DRAIN THE CAPS THEMSELVES. Why is this? Well, when we place two caps in series, we need to stabilize the voltage across them so that one does not pull any more voltage than it's brother. This is done by placing a resistor in parallel with each cap so that they are in balance with respect to the voltages that each one "sees." These resistors also serve a secondary purpose - they drain all of the voltage out of the cap once the power supply is turned off. This is why these resistors are also commonly referred to as "bleeder resistors." These resistors don't just drain the caps they're connected to - they will usually drain EVERY cap in the amp's HT circrcuit - even filter caps in different stages that they're not directly connected to. This being said, it's impossible to know what's inside YOUR amp without actually dismantling it or studying the schematic. It's worth noting that even if your amp DOES have bleeder resistors, you should STILL check across the caps with your meter (after the amp's been powered down for a few minutes with the standby switch "ON") to make sure that there's no residual voltage there before doing any work on it.

So...you've got the amp apart and need to drain the caps. How to do it? Well, here's ONE method I do NOT endorse. In this video, amp tech Cesar Diaz uses a screwdriver to directly short the caps to ground. This is NOT advisable because it's dangerous and can scar the chassis (and/or your screwdriver). It also creates a huge spark. I.M.H.O., it's all kinds of bad:

[ame=http://www.youtube.com/watch?v=hedZTu7S4HE]diaz mtn - YouTube[/ame]

My favorite cap-draining method is to take a simple jumper cable with alligator clips at each end and attach one end to the chassis. The other end goes to the pin 1 (or pin 6) connection at any preamp tube socket that uses a 12AX7 or any of it's relatives. Then just wait 1-2 minutes for the caps to completely drain and you're good to go. Leave the "standby" switch ON for this method. Be sure you use wire that's rated for at LEAST 600v and is 22awg or thicker in gauge. So...how does THIS method work? Pins 1 and 6 are the plate connections, and shorting them to the chassis shunts any voltage left in the caps to ground through the plate load resistors already in the amp! Still, this method assumes that the plate loaders are in good repair, so as ALWAYS, you'll need to check across each cap with your meter before proceeding further to make sure they're drained. In fact, I usually leave the jumper in place whilst working on the amp so that dielectric absorption (the phenomenon of the caps recharging themselves due to atmospheric conditions) doesn't rear it's ugly head and bite you! :think: Just remember to remove the jumper before powering up or you might get a NASTY surprise!! :mrgreen: Once again, I can't overstate that you should STILL check the caps with your meter before proceeding!!

The final method I'd like to discuss is to take a powerful resistor with jumper clips and directly short each cap to ground. This method is SIMILAR to the method Cesar Diaz used above, with the notable difference being that instead of directly shorting across the caps, we are using a high-wattage resistor drain the caps. This is MUCH safer and yields a less nasty spark. For this method, we just need to determine what value (and what wattage) of resistor will get the job done safely and effectively, and we can figure this out using ohm's law.

We know that 500v is the most voltage that can be in any single filter cap in a typical Marshall, Fender and most other amps. To determine which resistor would work to discharge a fully loaded filter cap (which is the "worst case" scenario), first we need to determine the current that would flow through that resistor using ohm's law. Lets start with an 11k, 10 watt resistor as an example...just to see what would happen:

I=E/R or Current=Voltage/Resistance, so:

I=500v/11,000 ohms = .045454545 amps.

Now, we plug that into THIS formula:

P = I^2 x R or Wattage=Current Squared times Resistance. Here we go:

P = .045454545 (squared) x 11,000 ohms = 22.72 watts. Thus, we can see that, at only 10 watts, This resistor is _not_ going to be able to safely handle discharging a fully loaded standard issue filter cap.

I myself use a 100k 5 watt resistor for this purpose, which is MORE than adequate for this task. How do I know this? Let's plug it into the same formula:

I=500v/100,000 ohms = .005 amps, and so:

P = .005 (squared) x 100,000 ohms = 2.5 watts.

I soldered two spare test leads I had to the ends of this resistor and covered the whole mess with heat-shrink to make it look nice and increase durability. Here's a picture of my apparatus. I call him "Mr. Bleeder:"






You can find a 5 watt 100k wire-wound power resistor here for a whopping 36 cents:

280-PRM5-100K-RC Xicon | Mouser

I hope that through the above methods you can figure out how to safely drain your filter caps AND determine which method works best for both you and the amp you're working on. Working on amps IS a lot of fun, but safety must come first and the filter caps should be checked before doing ANY work on an amp.

 Please stay safe, folks!

-Lane


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## Micky

GREAT post, as always!


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## Adwex

Yes, great post. Glad to see you again Lane.


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## thrawn86

Good to see you Lane! Always enjoy your posts.


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## core

Hi Lane! Great to see this post going so well  I'm coming in way late and it may have been answered. Stupid question, but I've always been curious, what exactly is going on when you power down an amp? As you keep playing through the amp you hear the guitar fade out for several seconds even though there is no power to the amp. My first thought is that it's draining any excess current left in the tubes but I've always been curious to exactly what is happening.

Cheers!


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## Lane Sparber

core said:


> Hi Lane! Great to see this post going so well  I'm coming in way late and it may have been answered. Stupid question, but I've always been curious, what exactly is going on when you power down an amp? As you keep playing through the amp you hear the guitar fade out for several seconds even though there is no power to the amp. My first thought is that it's draining any excess current left in the tubes but I've always been curious to exactly what is happening.
> 
> Cheers!



Honestly, it varies from amp to amp. Basically the "fade-out" you're hearing is, in fact, the _caps _draining until the tube filaments cool off to the point that they (the tubes) are not conducting anymore. Tubes don't actually store current, so that part of your statement was a bit off of the mark, to be honest. Once the filaments have cooled to the point that no more electrons are boiling off of the cathode and making the jump to the plate, the caps "hold on" to any stored electricity they have left at that point, assuming there are no "totem-pole" resistors in the circuit, like I mentioned earlier. 

Excellent question, Core! 

-Lane


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## core

Thanks Lane, great explanation! Ahh, I remember now about the tubes not storing current, they pass current. That's why they are called valves doh! 

Not to take the place of actually using any of the draining caps method when working on them I'd assume just to be safe.


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## All4Tone

Lane, this type of post adds so much value to this forum. The work you put into posting this info for the rest of us here is very much appreciated and you may have even saved someone from toasting themselves or their amp..

Cheers!!


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## bvoris

Hey Lane I just got through your entire blog. Thanks for keeping this up. There is a lot of really good info for everyone here. Thanks again also for the Mr. Bleeder LED version. Your recommendation I am sure has kept me from frying my sack while working on the few amps I have had the privilege to work on.


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## Lane Sparber

I'm glad you found it useful. Thanks again for all of the kind words!

I've been VERY busy recently, so anyone who wishes can see what I've been up to here, just like it says in my sig (looks like you have to be logged in to FB):

http://www.facebook.com/media/set/?set=a.1266486135987.41488.1044798875&type=3

-Lane


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## Kunnz

*LANE*

Your back!

havn't seen you about in a while, I hope all is going good with you, you F-----N genius


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## Lane Sparber

LOL!!

Thanks, Kunnz. High praise indeed, but I assure you - genius I ain't! 

I'm mostly "retired" from forum life, but I do like to stop by occasionally.

-Lane


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## Lane Sparber

*Measuring Plate Voltage*

I'm moving this post here (and making some edits), as people seem to be asking about it recently:

To measure the loaded plate voltage, pull the chassis from the amp and fully power it up - BOTH power and standby switches ON. Make sure ALL tubes are installed. Make SURE a properly matched speaker load IS connected. Turn all knobs to zero. Set your DMM to read D.C. voltage, and if it's not auto ranging, set it to the 500v (or higher) setting. Place the red lead of your DMM on PIN 3 or any power tube socket (for 6L6, EL34 and 6V6 tubes), and the black lead goes to the chassis (ground). You should get a voltage reading somewhere in the 400s, generally.

NOTE: If the power tubes are removed from the amp, the plate voltage will RISE, as the power tubes provide a resistive load to the HT supply. Also, with all power tubes removed from the amp, the output transformer is out of the circuit, so you technically do NOT need a speaker load hooked up to the amp in this case. That being said, always having the proper load connected to the amp when working on it is an EXCELLENT habit to get into. 

WARNING!!!!  See my sig!

-Lane


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## thrawn86

Good to see you again, Lane.


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## Lane Sparber

*Repairing Vintage Blackface and Silverface “Champ” and “Vibro Champ” Amplifiers*

The Blackface and Silverface “Champ” and “Vibro Champ” amplifiers present several unique repair and restoration challenges. Having worked on several, here are my findings – and what I do to correct the modern problems associated with these vintage amps.

First, the heater string needs to be re-done to minimize the noise it can induce into the signal path. Stock, one leg of the heater string references ground directly. This is FAR from ideal in terms of noise cancellation. I remove all of the heater ground references at the tube sockets, and completely re-wire the heater string using the standard “twisted pair.” I then attach the standard two 100 ohm false center tap resistors. However, instead of grounding these resistors directly, I run the resistors’ junction to the power tube cathode. This will elevate the heater string by about 20-35 volts with NO extra parts, and in tandem with the twisted pair, it makes the heater string all but silent. This is critical in “class A” single ended amps such as this.

Next, we need to look at the B+ rail voltages. Here’s where it gets a bit funky. In almost ALL of the Champs/Vibro Champs I’ve seen, the B+ is very, VERY high. I’ve seen it get as high as 420 vdc! This seems to be the case for all but the VERY earliest examples of these amps. The Champs’ power transformers mirrored the Princetons, and when the Princetons went with a push-pull design incorporating more voltage, the Champ’s PTs followed suit. To over simplify, the “AA764” circuit had the lower B+ on the schematic, and the “AB764” circuit reflected the higher B+ voltages.

At any rate, by the Silver Face era, ALL of these amps were blasting their 6V6 tubes with very high voltages. When you consider this phenomenon in tandem with the higher wall voltages we see these days, it can cause some very real reliability issues – especially considering the lower quality of current production tubes. 420vdc is a LOT on these 6V6s! In addition, this higher voltage can cause the power tube to exhibit an extremely harsh, un-musical distortion characteristic when pushed due to the EXTREMELY asymmetrical clipping on the top half of the waveform. The problem is that Fender didn’t update the cathode circuit on the power tube when it went with the higher voltage PT. There are two ways to correct this. If the amp has ALREADY been recapped, you can simply replace the 470 ohm resistor and 25uf/25 volt cap with an 820 ohm or 1k 2 watt (or better) resistor and change the cap to a 50uf/50volt cap. The reason for the difference in the cap specs is due to the fact that we are shifting the bias point with this resistor change, so in order to maintain a similar frequency shelving point, we need to shift the cap up. Also, since this new resistor will cause the voltage at the cathode to rise to 35-40 volts, we need a cap that can handle that higher voltage level. If the amp has NOT been recapped, I solve this high voltage issue a different way: I add an additional PI filter BEFORE the first pre-existing filter stage. The benefits of this method are two-fold. First, it removes exponentially more ripple from the DC B+ supply than the stock configuration does. Secondly, it allows us to drop the B+ to much more manageable levels for longer tube life using the correct value decoupling resistor. I’ve found that a 5 watt 1.5k or 2.2k resistor in this position will bring the B+ down to a much saner 340-360 target voltage. If you’re replacing the cap can with discreet capacitors, this is a relatively easy mod. If you want to replace the existing cap can with a new FP type from CE, they DO make a 20uf-20uf-20uf-20uf model that’s perfect for this application. If you choose this method, there is NO NEED to swap component values on the 6V6 cathode – it will fall right into spec without additional modification. I shoot for a target current draw of 35mA-43mA or so at the power tube. 

While we’re inside the amp, we should also examine are the existing filter capacitor values. At about the same time these amps were switched to the higher voltage, Fender began installing a 40uf-20uf-20uf filter cap can as well. A quick look at the datasheets for the 5Y3 rectifier tube tells us that the 5Y3 wants to see a 20uf capacitor on the output. Fender nearly doubled this. I always go with a 20uf on replacement. That being said, I’ve rarely, if ever, seen a blown rectifier tube in these beasts.

If the amp doesn’t have one already, it never hurts to install a 1k/5w screen resistor on the power tube socket. This will prolong tube life with current production tubes significantly.

Finally, be advised that with the AA764 and AB764 circuits, there’s a “quirk” with the “vibrato” footswitch control. While this switch WILL ground out the LFO circuit and stop the actual oscillation, there is STILL DC being sent from the vibrato circuit to the second stage cathode. This amount of DC voltage IS STILL MODULATED BY THE INTENSITY CONTROL! The effect of this is that when the oscillator is switched off, the “intensity” control will act as a secondary volume control and cut the amp’s volume to varying degrees depending on where it’s set. I usually just tell my clients that rather than re-design the LFO circuit, it’s better and cheaper to just disconnect the footswitch and turn both the “speed” and “intensity” knobs to zero when the tremolo function is not required. I haven’t had a complaint yet. 

In conclusion, these are GREAT amps for recording, practice, and even some live situations when maintained correctly. I hope these hard-earned pointers and tips will be useful to you during your next repair!


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## MartyStrat54




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## mickeydg5

Good read and nice bits of information.


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## Micky

When I re-worked my Princeton Reverb, I just couldn't wrap my head around the tremolo footswitch, and the strange way it worked. I didn't even think to check that it might bypass to the second stage. 

Thanks for the info Lane.


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## Lane Sparber

Micky said:


> When I re-worked my Princeton Reverb, I just couldn't wrap my head around the tremolo footswitch, and the strange way it worked. I didn't even think to check that it might bypass to the second stage.
> 
> Thanks for the info Lane.



Micky - your Princeton Reverb's vibrato footswitch operates in the EXACT same manner as the Vibro Champ - which is to say that it simply grounds out the positive feedback loop in the first triode of your "vibrato" tube. In the most basic terms, the three caps between the plate and grid of this triode form a positive feedback loop that reverses phase every time it goes through one of those caps. This is what generates the oscillation used in the vibrato circuit. Your switch just grounds out one node of this loop, effectively shutting it down. Where the two circuits DIFFER is that in your amp, the vibrato varies the bias voltage to your POWER tubes - sending them into cutoff repeatedly at a rate controlled by said oscillator. In the Vibro Champ, it controls the bias to a PREAMP triode. 

Check out Merlin Blencowe's article. As usual, he's a fountain of excellent info!

The Valve Wizard- Tremolo Oscillator

Hope this helps!

-Lane


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## lez57

*Re: Lane's Corner - Rangemaster kit assembly*

Hi Lane, that's a great looking kit. I was about to start making one when I came acrooss this. Do you know if they are still around. Their Facebook page is inactive and their website doesn't work. Cheers, Les


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## Lane Sparber

Hey, Les! 

Welcome!

I've recently noticed that their website and Facebook account seem to be inactive as well. I wish I had more info to offer you on their current state of affairs, but alas I do not. 

The GOOD news is that with about $20 in parts (not counting whatever enclosure you decide to use), you could build the whole thing into a pedal if you like. There are plenty of folks currently offering OC44 repros and NOS transistors as well on eBay. This circuit would work well in a pedal like that, and many manufacturers already offer such a thing. 

-Lane


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## Lane Sparber

*Repairing My Own 1974 Super Lead*

Hey, folks!

By request, here are some pics of the recent restoration I did to my own personal 1974 Super Lead. This amp was a 40th birthday present, and it was obtained at a KILLER price due to the fact that the seller NEEDED to sell and the amp had been modded. No worries, I was happy to have it, since it's the same vintage as me (1974)! As most of you already know, I enjoy the challenge of putting vintage amps back to stock, so no worries there. Here's what she looked like on the inside when I got her:





















Now, I wasn't looking for a museum piece, and this sure wasn't ever going to be one. I prefer to own beaten-to-death, abused road warriors rather than mint examples of an amp. That way, I'm more likely to gig and record with them, since I'm not super-concerned with maintaining their beauty. Not only was THIS old gal road tested to my satisfaction, there were no extra holes drilled in the chassis other than for a replacement PT someone had installed in the early 90s. SCORE! 

My objective was to remove all of the mods and restore it to stock using ONLY vintage components. What I found most surprising and uplifting about this project was the fact that as soon as I put out the word that I was looking for vintage '74 Super Lead parts, a LOT of my well-connected friends opened up their cherished stashes to help me out. Most notably from the Marshall Forum were Damien (DemonUFO) and "rtcook." I can't thank ALL of you guys enough for the extremely rare parts I needed to put this thing back together.

What was modded? Well, as you can see, there was a PPIMV installed, as well as extensive preamp modifications done - including (but not limited to) cascading the channels at the V1 socket, replacing cathode r/c values for the first three triodes, and a conversion to the "MK1" presence control. Also, those Sprague orange drops had to go. Almost all modding was done in the above the board "chop off the old component and solder the new one to the remaining leads of the old one" method that I HATE! Speaking of the board, an additional challenge was the board itself. These first-run Marshall PC boards from mid 1973-late 1974 were really poorly made. The traces were so delicate that if you even BREATHED on them they'd crumble. Thus, most techs (myself included) will replace components using new ones with extra long leads, and solder them directly to where the existing trace went. It might not be pretty, but the results of doing it this way are rock-solid, and more reliable than the original board was, IMHO. Here's a pick of what the underside of the board looked like mid-repair and cleanup:





Once all of the parts trickled in to my shop, here's what the finished product looks like now. Spot the differences!! 









I had some vintage 50s and 60s Mullard preamp tubes in my stash, and those went into the V1-V3 positions, with a REALLY sweet 1959 Blackburn in V1. The power tubes are my favorite current production EL34s for Marshalls, JJ EL34Ls. 









Now all I need is to hit the hardware store for a back panel and chassis screw and I'm done. This is now easily the best sounding amp I own…and my wife said she thinks so too! Well, actually what she SAID was that she could hear it from inside the car a block or two away, but I'll take that as a complement!

In addition to this being quite possibly the last amp I'll ever buy (my favorite Marshall model of all time from my birth year), it means all the more to me because of my friends from around the globe who hooked me up with rare, vintage parts when I needed them most. Therefore, this amp means the world to me…on several levels!

Cheers!

-Lane


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## Micky

Awesome job! Incredible to have you back here to show this beast off!


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## solarburn

Fun to watch the progression Lane. You gave it some sugar baby! 

Thanks for sharing and awesome job on a killer Marshall. Man that thing looks like it's been around the block a few times.LOL


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## MartyStrat54

I'm glad you found the parts you were looking for.


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## Lane Sparber

Hey, Gang!

I've recently re-tooled the incoming AC rig that I use to test and "burn-in" amplifiers on my workbench. I've synthesized ideas from several other techs that I mention in the video, and so far this new rig has proved to be INCREDIBLY helpful to me when diagnosing problems. Please check it out, and I hope you find it useful.

https://www.youtube.com/watch?v=FeMuZqqkMTU

Since this video was made, I've upgraded the Tripp Lite isolation transformer to the "ISO 1000" 9 amp model, but other than that this rig remains as it is in the video. You don't NEED an isolation transformer (they're pricey), but I use one for an added measure of safety.

SAFETY NOTE!!!! If you want to follow my lead and use a commercially available isolation transformer, I humbly suggest that you perform the slight modification to it that's outlined in THIS video for safety:

https://www.youtube.com/watch?v=11Yve2ijWyk

As usual, I wish all the best to my friends in Marshall Forum land. Happy repairing, everyone! 

-Lane


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## toadfish

The International sales b/¿ch at Stew Mac needs her head read! Or a couple of slaps! Suspended my account with over $1000 credit in it then wouldn't reply to emails! Shifty company! The amount of Australian's they have ripped off would surprise the hell out of people in the USA! but then again the likelihood of an Australian walking in to a Stew Mac shop to recover there money would be a percentage they feel safe with!


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## Lane Sparber

Hey! Just stopping by to say hello, and let everyone know that whilst I’ve “retired” from all forums and forum life, I can still be reached professionally on Instagram. Follow me if you wish here:

https://www.instagram.com/amptech74/?hl=en

So...how have y’all been?


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## LPMarshall hack

Lane Sparber said:


> Hey! Just stopping by to say hello, and let everyone know that whilst I’ve “retired” from all forums and forum life, I can still be reached professionally on Instagram. Follow me if you wish here:
> 
> https://www.instagram.com/amptech74/?hl=en
> 
> So...how have y’all been?


Great to hear from you Lane! Glad you’re doing good


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## mickeydg5

Its good to know you are still kicking.


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## paul-e-mann

Lane Sparber said:


> Hey! Just stopping by to say hello, and let everyone know that whilst I’ve “retired” from all forums and forum life, I can still be reached professionally on Instagram. Follow me if you wish here:
> 
> https://www.instagram.com/amptech74/?hl=en
> 
> So...how have y’all been?


What's up man hows it going!


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## Lane Sparber

pedecamp said:


> What's up man hows it going!


Going well!!! Busier than ever. Two kids, two jobs, crazy schedule. Wouldn’t have it any other way!!!


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