# Jcm800 2204 Build



## coolidge56

I purchased my first JCM800 recently the new Studio SC20H. Kind of fell in love with the little 20 watt's tone so for fun I have decided to scratch build a 2204 50 watt.

The first batch of components arrived lets have a look.

Mercury Magnetics power transformer P50JM-475.
Mercury Magnetics output transformer 050JM.
Mercury Magnetics choke MMC-3H.
Vishay BC 100,000 hour Polypropylene film filter caps, 5% tolerance.
Synergy Royal Mustard USA signal caps.
OHMITE 5W wire wound resistors.

Film caps continue to shrink in size. I have these drawn on the PCB/turret board and they fit fine.






Top view






Side view. The 50 watt power transformer is the same size as a 100 watt.






Comparing the size of the output transformer, here is a 100 watt on the left vs the 50 watt on the right.






This will be the first time I have used these Synergy Royal Mustards. Fingers crossed.






Digi-key misrepresented these TE Connectivity 3W power resistors on their site. I may go with a different brand.






Next I'll continue work on the CAD for the PCB/turret board.


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## ampmadscientist

coolidge56 said:


> I purchased my first JCM800 recently the new Studio SC20H. Kind of fell in love with the little 20 watt's tone so for fun I have decided to scratch build a 2204 50 watt.
> 
> The first batch of components arrived lets have a look.
> 
> Mercury Magnetics power transformer P50JM-475.
> Mercury Magnetics output transformer 050JM.
> Mercury Magnetics choke MMC-3H.
> Vishay BC 100,000 hour Polypropylene film filter caps, 5% tolerance.
> Synergy Royal Mustard USA signal caps.
> OHMITE 5W wire wound resistors.
> 
> Film caps continue to shrink in size. I have these drawn on the PCB/turret board and they fit fine.
> 
> 
> 
> 
> 
> 
> Top view
> 
> 
> 
> 
> 
> 
> Side view. The 50 watt power transformer is the same size as a 100 watt.
> 
> 
> 
> 
> 
> 
> Comparing the size of the output transformer, here is a 100 watt on the left vs the 50 watt on the right.
> 
> 
> 
> 
> 
> 
> This will be the first time I have used these Synergy Royal Mustards. Fingers crossed.
> 
> 
> 
> 
> 
> 
> Digi-key misrepresented these TE Connectivity 3W power resistors on their site. I may go with a different brand.
> 
> 
> 
> 
> 
> 
> Next I'll continue work on the CAD for the PCB/turret board.



What are the 200 volt caps for?


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## coolidge56

ampmadscientist said:


> What are the 200 volt caps for?



Are you asking about those .68u caps?


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## Yugedrums

Subscribed.


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## mickeydg5

What are all the little black boxes? Mouse traps?

(Its joke)


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## coolidge56

mickeydg5 said:


> What are all the little black boxes? Mouse traps?
> 
> (Its joke)



When two black holes merge they absorb the gravity waves and sweeten the reverb.


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## ampmadscientist

coolidge56 said:


> Are you asking about those .68u caps?




You have rectangular filter caps?


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## coolidge56

ampmadscientist said:


> You have rectangular filter caps?



Yes metallized Polypropylene film filter caps. Here's the product sheet. http://www.vishay.com/docs/49430/mkp1848c_vmn-pt0390.pdf


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## mickeydg5

yes, DC-Link capacitors


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## ampmadscientist

coolidge56 said:


> Yes metallized Polypropylene film filter caps. Here's the product sheet. http://www.vishay.com/docs/49430/mkp1848c_vmn-pt0390.pdf



Yes, I have only seen pictures of these and never had any to play with. Looks like some fun.
F&T is making these too.


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## coolidge56

ampmadscientist said:


> Yes, I have only seen pictures of these and never had any to play with. Looks like some fun.
> F&T is making these too.



Yep the future has arrived. The amp basically will never need to be re-capped. If someone played the amp 2 hours a day 5 days a week it will be 200 years before the caps need to be replaced. ESR/ripple is a tiny fraction vs electrolytic. Less ESR less heat. 5% tolerance. Higher voltage rating etc.


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## coolidge56

ampmadscientist said:


> Yes, I have only seen pictures of these and never had any to play with. Looks like some fun.
> F&T is making these too.



Those look sweet. Sadly I don't see a supplier for them here in the USA.


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## junk notes

very _cool,_ 56 ;-). Always nice to see a build populate.

Yes those caps sound hi-fi in their info. Which is what you probably want in an audiophile build.


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## coolidge56

First build with film filter caps so we'll see how this turns out tone wise.


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## ampmadscientist

coolidge56 said:


> First build with film filter caps so we'll see how this turns out tone wise.






Digikey has 20uF 700 V 105C rated 100000 hours at 70C for $11.20 80uF $32.98

I like the specs, that sounds like something I could use....

* lifetime rating of a standard filter cap is typically 5000 hours at rated temperature.
This cap is supposed to last like 20 times longer.


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## coolidge56

ampmadscientist said:


> Digikey has 20uF 700 V 105C rated 100000 hours at 70C for $11.20 80uF $32.98
> 
> I like the specs, that sounds like something I could use....



Link to that cap?


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## FourT6and2

Interesting. Looking forward to seeing how this turns out.


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## ampmadscientist

coolidge56 said:


> Link to that cap?



https://www.digikey.com/en/product-...SfTwuMUGssoA5fRG2vDu_xXwxzbeuUpRoC6B0QAvD_BwE




The caps have no polarity, you can hook them up either way works.


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## coolidge56

Turret/PCB first draft.

Preamp 90 x 330 mm






Power Supply 100 x 160 mm


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## clutch71

In for the build process. Appears your making your own PCB? I'd like to hear more about that.


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## coolidge56

clutch71 said:


> In for the build process. Appears your making your own PCB? I'd like to hear more about that.



These are amazing times we live in. Having custom PCB's manufactured once required minimum orders of 500 boards and expensive PCB CAD software costing thousands of dollars. Today the minimum order is 10 boards and the software is a free download.

Here in the USA there are a number of companies who act as the brokers between you and the PBC manufacturers in Asia. You work with the USA company on your order and pay them.

Some of these USA brokers have their own PCB design software they require you to use. I use an independent PCB CAD software called DesignSpark PCB 8.1. Its a free software not tied to any particular broker. This software is easy to use and will generate all the files the PCB manufacture in Asia will require to manufacture your boards. You click a button in DesignSpark PCB and it builds the files for you. You email these to the broker and they take care of the rest. A week later your boards arrive at your door.

The PCB CAD software gives you very precise control over your board design. Mine are accurate to .25mm. They could have been accurate to .1mm but .25mm is all that is required for the pin spacing on those film capacitors and 95% of the board is laid out at .5mm. There is a snap to grid feature in the software. Set it to .5mm and you can drag caps and resistors around your board and they will snap align to this .5mm grid making spacing and layout of the board really easy.

You don't have to settle for cheap, thin, green PCB boards although those are less expensive. My PCB specs are pretty beefy. .125 inch thick boards, that's really thick for a PCB. Copper is spec'd as 2 oz, again that's pretty thick vs the typical 1/2 oz copper used on cheap PCB's. 2 oz copper gives you quite thick solder pads and traces.

I also spec plated through holes so you have a thick copper pad on the top of the board, a metal through hole and a thick copper pad on the bottom of the board, all connected and sandwiched with the board in-between. Kind of like a rivet with a hole in the middle. This is quite stout. Next I spec black for the board color not green and the top of the board is silk screened with white text and labels.

Finally I have precise control over the plated through holds for turrets. They are sized to the Keystone turret shanks, plus a little wiggle room allowed for variance in turret shank size and manufacturing tolerance of the plated through hole. Still a nice fit, better than you can achieve hand drilling a turret board. Your turrets will be staked into a plated through hole with thick pads on the top and bottom giving you a strong mechanical assembly. I take the added step of soldering the turret at the bottom of the board. So mechanically staked to a metal plated through hole and soldered. ROCK solid.

The 10 board minimum while doable still costs a bit. With my specs a 10 board order with shipping is going to cost somewhere in the $800-$1,000 range. I don't mind paying this to get what I want but others could chose to organize a group buy to lower the cost to $80 to $100 per board.

Another trick to keeping the cost down is this. 1 board cost less than 2 separate boards. The preamp board is currently 90mm wide, the power supply board is 100mm. I will widen the preamp board to 100 and combine both into a single board for ordering. You can leave these as one long board or specify a score line between the two boards so you can snap them apart.

There you have it!

Caution: My .125 inch thick spec boards are so thick you need to keep an eye on component lead length for things like those small PCB film capacitors. Some will have leads that are too short for the board thickness. So check lead length before ordering caps or other PCB lead type components.


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## coolidge56

Another round of board revisions...

Preamp board...

Now 90 x 310 mm (3.5 x 12 inches). I shaved 20mm (.78 inches) off the length by tightening up the component spacing.
Switched to the larger Keystone multi-component turrets.
Increased turret and wire solder pads from 5mm to 6mm.
Sourced 470pf (KEMET) and 47pf (WIMA) film caps with leads long enough for the 3mm (.118) thick boards.
Trace revisions.






With the bottom solder hidden.






Power Supply...

Bias supply now uses 2W Vishay flame retardant power resistors. Still overkill vs the 3W but quite a bit smaller. I was able to swing most of the bias supply components down along the bottom of the board.
Bias supply now has separate HT power before the standby switch not after.
Also switched to the larger Keystone multi-component turret and larger 6mm solder pads.
Trace revisions.
Daughter board added for PCB high/low guitar input jacks. I'm borrowing an idea from my Marshall Studio Classic. The jacks are still chassis mounted but now anchored at the rear with this thick daughter board. I was also able to locate the 470k/470pf components on the board instead of floating in mid air. Wire pads for all connections vs soldering to the jack lugs.
Daughter boards (small, medium) added for the V1, 7 68k and V4-5, 5.6k resistors. I like a board there vs them hanging loose off a wire.
Daughter boards will be scored at the white lines so I can snap them apart.


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## Exojam

That is some very cool stuff right there.

Dumb ass question but how did you how everything needed to be laid out on the boards?


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## coolidge56

Exojam said:


> That is some very cool stuff right there.
> 
> Dumb ass question but how did you how everything needed to be laid out on the boards?



Not a dumb question at all. I started with this layout someone posted on the Metroamp forum years ago. This shows all the connections, component values and placement. I started here then modified to adapt to my choice of components and layout.


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## coolidge56

Here is the latest version. I'm very close to submitting my order to have the boards made. I just need to perform a quality check to make sure I haven't made any mistakes on traces, connections.

I ended up going with a modular design, separate boards.

Board 1 on the left is the preamp board.

Board 2 holds 2x50uF filters caps for V1 and V1 preamp tubes. Separate and modular so I can locate it over near these tubes. But not on the preamp board which would have spread the components out wider, farther away from the three preamp tubes.

Board 3 holds 4x50uF filter caps, 50uF,50uF, and 50+50uF for V3, V4 and V5 and the main 50+50uF filter caps after the rectification. Modular so I could mount them in the chassis at a remote location over near the power transformer.


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## coolidge56

So why one giant long board? Because its much less expensive to have a single board manufactured than multiple boards. The red lines are router lines, they will use a router to cut out all these individual boards.

See the red/black heater wires. The layout drawing above is a bit deceiving, the reality is strong arming the heater wires is a bit bulky and annoying. Then because you need to string the heater wires together from tube to tube you end up having to solder 2 wires per tube socket solder lug. Teflon wire which I'm using now has much thinner insulation than this wire but still.






I'm fixing this issue with these little micro boards. You see two rows of turrets, one for the red and one for the black wires. With a center turret where the wire will attach to the tube socket. These will be mounted along the edge of the chassis to bring the heater wires to each tube.






Here's another micro board change. See the 5.6k resistors which are magically floating in mid air, I don't like that. Also the 5W 1k resistors are easily twice as big as shown in this drawing. You end up having to bend the leads 90 degrees, then 90 again, and 90 a third time to attach to pin 6 and 4 of the tube socket. Pin 6 doesn't do anything, they are just using it here for an attachment point.






Instead I'll mount one of these small 2 turret boards near the tube sockets, attach one end of the resistor to the board and the other to the tube socket.






Here's another problem area. See all the grounds soldered to this buss wire that runs along the pots, in reality this becomes a big glob of soldered mess.






Instead I'll use this small turret board to bring these ground wires together neatly, and a single wire up to the buss wire on the pots.






The traditional way to mount the guitar input jacks. I have always found soldering these up annoying, tight quarters, and I hate how the 470pf cap is globed onto the 470k resistor and how the pair float in mid air.






So I'm borrowing from my Marshall SC20 Studio. I'm mounting the input jacks to this small board with solder pads for these two components. This board material is .125 thick that is very thick indeed. With plated through holes. This method is way stronger. The two jacks anchored to this thick board, then screwed to the chassis is quite a rigid structure vs just screwing the above jacks to the chassis individually. These are plastic nylon jacks and a bit flexible so they can benefit from some beefing up. Plus I can solder these up on my bench vs trying reach down into the chassis with my iron to solder them in place.






Finally this little 1.25 x 2 inch board is for the 12vdc power supply. I'm still amazed how small it is (.875 x 1.3 inch). For now this will drive the power on/off LED light, and maybe an on/off effects loop LED. I was thinking about using some relays for switching but decided against the idea. I could have used the heater power transformer tap then rectified, filtered, to get 5vdc for the LED's but what a hassle. This was easier and neater.


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## Exojam

Cannot wait to see this board as it appear it is going to be nice and stout. I wish manufacturers would make boa do like these.

The boards being shipped now are some damn thin, with crappy solder pads, trace runs etc. 

There was another gentleman on here and he also had his own boards made up like yourself and man did they look great.


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## coolidge56

Exojam said:


> Cannot wait to see this board as it appear it is going to be nice and stout. I wish manufacturers would make boa do like these.
> 
> The boards being shipped now are some damn thin, with crappy solder pads, trace runs etc.
> 
> There was another gentleman on here and he also had his own boards made up like yourself and man did they look great.



They will look like this only with larger turrets. Trivia, when I ordered this set of boards the manufacturer forgot to score between the boards so I had to cut this power supply board free from the preamp board with a scroll saw. About 2/3 across all the teeth on the scroll saw blade were sheered off ahahaha! Tough thick boards.


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## petercornell

Great looking build! Following.


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## coolidge56

A few more refinements this morning. Mostly just swapped some wire attachment points around.


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## coolidge56

Boards are now INBOUND! I got the routing to separate the boards sorted out with the PCB manufacture and ordered this week. ETA May, 14th.

.125 inch thick IFR4
Plated through holes between the top and bottom copper pads
Black solder mash top and bottom with white silk screen labels
Screw holes are #8 on preamp and filter cap boards. #6 on the smaller turret strip boards (right).
Ordered large and medium Keystone turrets from Digikey.


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## coolidge56

Well now look what just arrived!


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## Amadeus91

coolidge56 said:


> Turret/PCB first draft.
> 
> Preamp 90 x 330 mm
> 
> 
> 
> 
> 
> 
> Power Supply 100 x 160 mm


I salute you sir. Damn, that is cool.


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## Amadeus91

Just saw the updates, Outstanding!


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## coolidge56




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## Gunner64

Nice. I always build with traditional turret boards but now I have some new Ideas.. 
Looks expensive though..


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## Fender

I love PCBs with turrets


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## coolidge56

Staked the boards this morning.


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## coolidge56

I smell solder fumes...


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## CoyotesGator

Very cool!


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## mickeydg5

Oh that shits perty.


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## petercornell

That is exquisite!


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## Exojam

Are you going to allow others to use the gerber files?

And those are some badass boards and caps.


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## Exojam

coolidge56 said:


> Yes metallized Polypropylene film filter caps. Here's the product sheet. http://www.vishay.com/docs/49430/mkp1848c_vmn-pt0390.pdf


Do you mind letting me know where those black Vishays are going to be used? I have a 50 watt clone that would probably be using the same or close values and I might be interested in swapping those into my build. Thanks.


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## coolidge56

Exojam said:


> Do you mind letting me know where those black Vishays are going to be used? I have a 50 watt clone that would probably be using the same or close values and I might be interested in swapping those into my build. Thanks.



I'm using them for all filtering. Main 50+50uf filter, power tube filter, PI, V1 and V2 pre-amp, even using 10uf's for the bias.


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## Exojam

Thank you!


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## Exojam

Could you provide me a link to the business you ordered those caps from?

Thanks James


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## coolidge56

Exojam said:


> Could you provide me a link to the business you ordered those caps from?
> 
> Thanks James



I ordered them from Digikey.


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## coolidge56

Exojam said:


> Are you going to allow others to use the gerber files?
> 
> And those are some badass boards and caps.



Sure, I'm using DesignSpark PCB 8.1 its a free download. Happy to share the file. Then people can modify if they wish. DesignSpark PCB generates the gerber files.


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## coolidge56

Exojam said:


> Could you provide me a link to the business you ordered those caps from?
> 
> Thanks James



Here are the 50uf filter caps. https://www.digikey.com/product-det...PaTgzTFNhRWZPSm9jNXAwNURHU0JSSGRsTVN1VGdiZCJ9


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## Exojam

Man, that has to be the sweetest amp board I have ever seen!

Thank you very much for the other information also.

James


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## paul-e-mann

coolidge56 said:


> Here are the 50uf filter caps. https://www.digikey.com/product-det...PaTgzTFNhRWZPSm9jNXAwNURHU0JSSGRsTVN1VGdiZCJ9


How do you keep everything so straight and uniform? I've never seen anything like it!


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## Fender

love of straight lines of components in PCB-design I guess.


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## coolidge56

pedecamp said:


> How do you keep everything so straight and uniform? I've never seen anything like it!



Pretty simple. First the silk screen on top of the board has a box printed on it the same size as the component to help 'eye' center. Second with these turrets there's a trick. If you lay the component, say a resistor across the two turrets, first center using the printed component box as a guide. Then if you rest your wire cutters against the outside of the turret and snip off the excess this will leave about .1 inch to bend over at 90 degrees with the component still centered. Then hook that end in a turret, snip off the other end the same way using the outside of the turret as a guide to length and presto its centered.

I do take some time straightening the component leads. Typically the caps arrive with the leads bent up, annoying. The other challenge is the cap leads are not always centered in the cap they are frequently offset like a bent axle. Just rotate the cap for best centering of the leads looking down at the top of the board. This is just a craft hobby for fun, as such I don't mind taking the time to make it look pretty.

Here's what's really important, two things.

1. I measure every component with a BK Precision meter to confirm the value before soldering in place. Its rare that I reject a component because the components I'm using are typically accurate to 1% or 5% but on occasion I do find one that's whacked out way off from the stated value.

2. I use heat sinks while soldering every component to keep the heat away from the component, to avoid cooking it. They make these little flat tipped alligator clips, you can find them on Digikey. They have no teeth so they won't mar the component leads. I clip one on each side of the component before soldering.


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## Exojam

Probably another dumb ass question but since I have never seen someone do this, how did you go about determining which components you would use turrets for and which ones would be using solder pads?

Thanks, James


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## coolidge56

Exojam said:


> Probably another dumb ass question but since I have never seen someone do this, how did you go about determining which components you would use turrets for and which ones would be using solder pads?
> 
> Thanks, James



For the larger black film filter caps turrets are not possible, they are designed for solder pads and leads are not long enough to use turrets. Plus they are rated for 100,000 hours so I'll be long gone from this world before they need to be replaced, if ever. For those two 470pf film caps on the main board I relented and used solder pads mostly for best spacing. I shifted things around on the board a number of times to reduce the length of the board. Plus those small caps perched on top of turrets would have looked pretty awkward. I should mention I wanted film caps for those 470pf not silver micas or ceramics. If I had uses silver micas I likely would have used turrets there.

For the main board lead wires to pots and tube sockets I waffled back and forth between using turrets or solder pads. Turrets seemed overkill since the board has plated through holes with solder pads on both sides. With solder pads I have the option of soldering the wires on either side of the board. Insert them from the bottom (Marshall) or down from the top (SLO 100). I will solder all those wires to the board before installing the board in the chassis, then trim and solder out to the pots and tube sockets. For wires coming to the board from filter cap boards, PT, etc. that I will have to solder after the board is installed into the chassis (and where I have 2 or more wires coming in to a single location) I used turrets.


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## Exojam

Thank you.

I did download the program last night and have been watching a few of the video tutorials on how to use it.

I am trying to see if Pass Labs still makes their gerber files for their Pearl 2 boards available as I would like to try and mod them a bit. If not I do have the schematic available and could go about it that way.

If I may ask, what business did you use for the actual board manufacturing?

Thanks, James


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## coolidge56

Exojam said:


> Thank you.
> 
> I did download the program last night and have been watching a few of the video tutorials on how to use it.
> 
> I am trying to see if Pass Labs still makes their gerber files for their Pearl 2 boards available as I would like to try and mod them a bit. If not I do have the schematic available and could go about it that way.
> 
> If I may ask, what business did you use for the actual board manufacturing?
> 
> Thanks, James



Reach out to Michelle at michelle@pcbprime.com For the record I have no affiliation with this company I'm just a satisfied customer. Be advised there is a minimum limit of 5 boards. And 5 boards cost more per board than 10, 10 more per board than 15, 20 etc. Also be aware of all the board upgrades I opted for, .125 inch thick, plated through holes, 2 oz copper, silk screen, bottom and top copper, etc. These drive up the cost a bit. I also had them router the main board and all the smaller boards apart into individual boards. This vs tab routing or V scoring. Came out fantastic I was really happy with that.

On that note be advised its MUCH less expensive to submit a single board for manufacture e.g. the main board and all the other smaller boards as one unit then have them router the boards apart vs submitting 2 or multiple individual boards.


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## Exojam

Thank you again!


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## Gunner64

Sweet. Makes me want to throw every amp I've ever built in the pool..thanks for that....you should sell them as board/parts kits.


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## coolidge56

Gunner64 said:


> Sweet. Makes me want to throw every amp I've ever built in the pool..thanks for that....you should sell them as board/parts kits.



Or...some of you guys could organize a group buy and place an order for boards. I emailed Exojam the DesignSpark CAD file the other day.


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## coldengray

These boards are fantastic. Can we please do a group buy?


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## Exojam

So far I have not had a chance to dig into that much but when you just load the file you can see how very neat coolidge56 has all the boards layed out in a very organized manner.

Once I get some more time I will play with it more, I just need to remember to never save any changes I make messing around or just have a master copy in another location.


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## neikeel

coldengray said:


> These boards are fantastic. Can we please do a group buy?


I’happily join in for one.


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## Exojam

Damn coolidge56, you must have done something very right to get niekeel interested.

I wish I could join in but the funds are not available.


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## ampmadscientist

coldengray said:


> These boards are fantastic. Can we please do a group buy?



The board may look good, but how it sounds remains to be seen.
You see, the sound of a tube amp is largely the layout. There is a lot more going on than what is on the schematic.
So just because you laid out parts neatly, side by side, does not mean it's going to sound good.


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## coolidge56

ampmadscientist said:


> The board may look good, but how it sounds remains to be seen.
> You see, the sound of a tube amp is largely the layout. There is a lot more going on than what is on the schematic.
> So just because you laid out parts neatly, side by side, does not mean it's going to sound good.



Its laid out the same way Marshall laid them out no worries.


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## FourT6and2

pedecamp said:


> How do you keep everything so straight and uniform? I've never seen anything like it!



Wiring up turret boards is my fave part of building an amp


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## charveldan

Probably the easiest & most fun too.


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## Exojam

Please provide us your explanation on how this setup will sound of the amp? 

I and others would be interested your explanation.

I for one cannot see how his setup will have any bearing on the sound quality.



ampmadscientist said:


> The board may look good, but how it sounds remains to be seen.
> You see, the sound of a tube amp is largely the layout. There is a lot more going on than what is on the schematic.
> So just because you laid out parts neatly, side by side, does not mean it's going to sound good.


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## ampmadscientist

Exojam said:


> Please provide us your explanation on how this setup will sound of the amp?
> 
> I and others would be interested your explanation.
> 
> I for one cannot see how his setup will have any bearing on the sound quality.



I will give you 1 example:
If 2 audio coupling caps are placed side by side, they radiate into each other. And what is essentially between these 2 caps "is" a third capacitor.
The air space between the 2 caps is forming another cap, through which audio may travel...


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## coolidge56

ampmadscientist said:


> I will give you 1 example:
> If 2 audio coupling caps are placed side by side, they radiate into each other. And what is essentially between these 2 caps "is" a third capacitor.
> The air space between the 2 caps is forming another cap, through which audio may travel...



I call BS on this nonsense. Unless you are prepared to say Metropoulos Amps has been doing it wrong all these years?


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## ampmadscientist

coolidge56 said:


> I call BS on this nonsense. Unless you are prepared to say Metropoulos Amps has been doing it wrong all these years?



I never said anybody was doing it wrong. That was not the point.
Also what I just told you is the whole key to building the best sounding amp possible. It is certainly not nonsense.


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## coolidge56

FourT6and2 said:


> Wiring up turret boards is my fave part of building an amp



I LOVE how clean your board is, its spotless! As I work down the board soldering I shield everything except the component I'm working on with wax paper and blue painters tape. This keeps the solder spatter mess off the board and components.


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## coolidge56

ampmadscientist said:


> I never said anybody was doing it wrong. That was not the point.
> Also what I just told you is the whole key to building the best sounding amp possible. It is certainly not nonsense.



Lets agree to disagree then, I'm done here.


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## coolidge56

A few of you have expressed interest in doing a group buy of these boards. How about I just send you one for free?

Before you answer a couple of things. I'll only ship to the U.S. sorry but I don't want to hassle with international shipping. I'm donating 5 of the 10 boards I ordered so that's how many are available. Consider that these boards won't fit some off the shelf chassis you would need to modify to fit the board mounting hole locations.

Since Exojam, coldengray, and neikeel expressed an interest in a group buy they have first dibs.


----------



## coolidge56

Free boards going once...going twice...


----------



## paul-e-mann

coolidge56 said:


> Free boards going once...going twice...


I wish I could take one but I'm not a builder, I love what you've done with the one you put together, I'm looking forward to you getting this amp built and show off a demo!


----------



## Exojam

I would definitely like one and greatly appreciate the offer, very kind of you!


----------



## Paul H.

Birmingham, England....
Looks like there’ll be some lucky people over on your side.
Looking forward to the completed build.


----------



## FourT6and2

coolidge56 said:


> I LOVE how clean your board is, its spotless! As I work down the board soldering I shield everything except the component I'm working on with wax paper and blue painters tape. This keeps the solder spatter mess off the board and components.



Thanks!

I never seem to get much splatter. I just use a good iron and maybe the type of solder and its diameter I use helps? I use Kester 63/37. That and I figure splatter is from outgassing, right? The rosin flux boiling off. So the angle and speed at which you feed solder will affect how much splatter you get. Just my theory, but it seems to work.


----------



## Paul H.

Gone very quiet over here....
I’ve been watching this thread (from the UK) with real interest. 
Any news?
Progress?

Cheers, Paul H.


----------



## Filipe Soares

Man! I'm moist!!!

That boards looks incredible!!!!! AMAZING!!!!

if by any chance you'll sell some of them, send me a message.


----------



## coolidge56

Filipe Soares said:


> Man! I'm moist!!!
> 
> That boards looks incredible!!!!! AMAZING!!!!
> 
> if by any chance you'll sell some of them, send me a message.



Thanks! I have been distracted by Tele's the past month or so...meet the Texas Twins






*Luna* 2003 Highway One Texas, Glendale stainless single cut bridge plate, Gotoh Titanium compensated saddles, DiMarzio Area Hot T and Area T pickups, Gotoh vintage locking tuners, black Fender Bakelite pickguard, Ash body, 12 inch radius fretboard, tall/narrow frets.






*Psycho* 2008 Highway One Texas, Glendale stainless single cut bridge plate, Gotoh brass compensated saddles, SD Quarter Pound pickups, Gotoh vintage locking tuners, black Fender Bakelite pickguard, Ash body, 12 inch radius fretboard, tall/narrow frets.


----------



## CoyotesGator

coolidge56 said:


> A few of you have expressed interest in doing a group buy of these boards. How about I just send you one for free?
> 
> Before you answer a couple of things. I'll only ship to the U.S. sorry but I don't want to hassle with international shipping. I'm donating 5 of the 10 boards I ordered so that's how many are available. Consider that these boards won't fit some off the shelf chassis you would need to modify to fit the board mounting hole locations.
> 
> Since Exojam, coldengray, and neikeel expressed an interest in a group buy they have first dibs.




I'll gladly pay for one if you have any left.

Cheers!


----------



## coolidge56

CoyotesGator said:


> I'll gladly pay for one if you have any left.
> 
> Cheers!



I'll try to get some boards boxed up early this week guys. PM me your mailing address. As a reminder I will ship only to the continental U.S.


----------



## Exojam

Update?


----------



## Fender

yeaaah we'd love to see the board mounted and wired in the cab !


----------



## Paul H.

+1
And sound....


----------



## Guitar-Rocker

I'd gladly pay for one too.


----------



## Exojam

Can filter caps use only two pin caps as the ones in the below quote?

I was looking at my build which is a 50 watt plexi and mine are showing 3 pin filter caps, 2 being positive and 1 being hooked to ground.



coolidge56 said:


> Yes metallized Polypropylene film filter caps. Here's the product sheet. http://www.vishay.com/docs/49430/mkp1848c_vmn-pt0390.pdf


----------



## Exojam

Did you put together a parts listing?


----------



## coolidge56

Exojam said:


> Can filter caps use only two pin caps as the ones in the below quote?
> 
> I was looking at my build which is a 50 watt plexi and mine are showing 3 pin filter caps, 2 being positive and 1 being hooked to ground.



Technically yes, practically speaking no. A single 50uf film cap rated for 50 watt voltages is quite large physically about 1x2 inches. The cap you are describing is a dual 50uf/50uf cap with a common ground, this is common for electrolytic caps. I'm not sure if anyone makes a dual film cap but a 50uf/50uf film cap rated for these voltages would be quite large and likely too tall to fit within the typical guitar amp chassis.

On this subject when shopping even for single 50uf film caps, they come in a bunch of different sizes. Older stock typically are larger than newer stock. The length, width, height varies. Sometimes a cap with a higher rated voltage is smaller, another indication of older stock vs newer stock. These film caps continue to shrink in size over time with improved manufacturing methods. So search on 50uf, in a voltage rating range of 500vdc to 900vdc (watch the VAC ratings). Start with the size format that best fits your needs. That could be a higher voltage rated cap in a smaller size, and likely more expensive, vs a larger cap with a lower voltage rating and lower price.


----------



## coolidge56

In other news my amp project continues to be on hold due to my day job work has been insane. Likely no time for it until the major holidays later this year.


----------



## CoyotesGator

coolidge56 said:


> In other news my amp project continues to be on hold due to my day job work has been insane. Likely no time for it until the major holidays later this year.



Such is life. 

If you only knew what my Laboratory looked like, full of life moments. 

Cheers!


----------



## Fender




----------



## coolidge56

CoyotesGator said:


> Such is life.
> 
> If you only knew what my Laboratory looked like, full of life moments.
> 
> Cheers!



I purchased 2 Tele's, 2 banjos, and 1 acoustic the past few months, plus some recording gear...none have been played yet due to work/life insanity (face palm)


----------



## Steverino1984

I get it, coolodge56, sometimes important/work/family life precludes (also important) fun/recreation/play life. In my experience, the former generally provides resources for the latter. 
I’m confident no one is more anxious to get back to the guitars, banjos, recording and amp stuff than you!


----------



## coolidge56

Exojam said:


> Update?



Here's an update...I just got home from a work trip 20 minutes ago and I'm off again Monday morning for another one. Plus I see the grass needs mowing...and the check engine light came on in my $74k truck on the way home from the airport  Wait for it...LMAO my life.


----------



## mickeydg5

coolidge56 said:


> Here's an update...I just got home from a work trip 20 minutes ago and I'm off again Monday morning for another one. Plus I see the grass needs mowing...and the check engine light came on in my $74k truck on the way home from the airport  Wait for it...LMAO my life.


Use burnin oils?


----------



## Exojam

Well that sucks but at least your health is there.

What truck do you have a Raptor?


----------



## coolidge56

Steverino1984 said:


> I get it, coolodge56, sometimes important/work/family life precludes (also important) fun/recreation/play life. In my experience, the former generally provides resources for the latter.
> I’m confident no one is more anxious to get back to the guitars, banjos, recording and amp stuff than you!





Exojam said:


> Well that sucks but at least your health is there.
> 
> What truck do you have a Raptor?



No my health has taken a nose dive also (censored). You know damn Ford, a 6 cylinder Raptor...REALLY?? Total turn off. I drove one, talk about gutless off the line. I'm driving a 6.7 diesel super duty...wait for it...440hp and 925lbs torque. It will do a burn off at 40mph LMAO!


----------



## Matthews Guitars

It is a fact that there are factors in play where the relative position of components affects performance. There is a somewhat obscure subset of electronics knowledge called "circuit constants" and by adjusting relative component locations you can change the character of the amp. Capacitors and other components close together do exhibit mutual capacitance and mutual inductance as well. You have to be careful with wire dress and routing. Manage wire lengths and how they are routed.

I've worked on equipment where wire dress was critical to the unit simply OPERATING. You might say that if it was that critical, then the design itself was suspect, but when the wire dress was right, the unit operated to designed specifications reliably and without issue.

Randall Smith tells tales of spending many hours adjusting component locations and wire dress in prototype amps in order to achieve a certain sound, and when it's achieved, freeze the PC board design so that those distributed capacitances and inductances are reliably replicated in prodution amplifiers.

If you disagree with the notion that electronic components interact with each other due to their relative positions, then you DON'T know electronics. Inductive and capacitive coupling is very real. And it becomes ever more important as frequencies get higher. At microwave frequencies, it DOMINATES circuit layout.


----------



## coolidge56

Matthews Guitars said:


> You have to be careful with wire dress and routing. Manage wire lengths and how they are routed.



My last 100 watt Plexi build was so quiet with the volume on 5 I thought it was broken. True story.


----------



## coolidge56

All this talk of amp building...while my work schedule is insane I could finish the CAD for the chassis and have it made.  You know, after the tow truck driver gets here and hauls the Ford to the dealership and I get a loaner, come home and hose all the coolant off my driveway.


----------



## ibmorjamn

coolidge56 said:


> Here is the latest version. I'm very close to submitting my order to have the boards made. I just need to perform a quality check to make sure I haven't made any mistakes on traces, connections.
> 
> I ended up going with a modular design, separate boards.
> 
> Board 1 on the left is the preamp board.
> 
> Board 2 holds 2x50uF filters caps for V1 and V1 preamp tubes. Separate and modular so I can locate it over near these tubes. But not on the preamp board which would have spread the components out wider, farther away from the three preamp tubes.
> 
> Board 3 holds 4x50uF filter caps, 50uF,50uF, and 50+50uF for V3, V4 and V5 and the main 50+50uF filter caps after the rectification. Modular so I could mount them in the chassis at a remote location over near the power transformer.


How much would the that cost ? I have some software that does PCs schematics and will build a board but I’m not well versed in using it.


----------



## coolidge56

ibmorjamn said:


> How much would the that cost ? I have some software that does PCs schematics and will build a board but I’m not well versed in using it.



Okay lets empower you guys to craft your own boards. First up I use DesignSpark PCB. Its a free download and easy to use. Lets walk through a few important steps.

1. Here I have clicked Output/Manufacturing Plots to open this Output Manufacturing Plots popup window. This will generate several files that you need to send to the PCB manufacture so they can manufacture your boards. On the left you see the plot layers I selected for the boards. Everything except the copper paste. To the right on the Output tab note I selected *Gerber*.






2. Here is the Layers tab. Note that I selected Board Outline and Top Silkscreen. The board outline will be used to route the boards, just what it sounds like they use a router to separate the individual boards more on that below.






3. On the Position tab you see the size of the board 25.35 x 3.5 inches. It adds a .0025 buffer. So one giant board with a bunch of individual boards defined by the board outlines for each.






4. Here I zoomed in so you can see what's going on. The green border is the board outline. This will be the outside edge of each board after routing. The red lines are the paths for the router bit. There is .100 inch between all boards, that's the waste material the router bit will remove. So .050 inch spacing either side of the center red lines. The white boarders are part of the white silk screen layer. Technically they are not required on these small boards since its just a printed white boarder but turns out they look pretty cool.






Its MUCH less expensive to design a single large board with all these multiple boards on it, routed to separate the boards from one another vs having individual boards made say one for the preamp and a 2nd for the power supply.

GET CREATIVE - I added some additional length to the board and added a bunch of small boards. One for the two guitar input jacks for example, an idea I borrowed from my Marshall Studio SC20H. I used PCB mount cliff jacks. These jacks still attach to the chassis with the classic Marshall chrome nuts so they are chassis mount. But I'm tying the jacks together on a brute .125 inch thick PCB mini board on the back side which makes them even stronger. Plus I have a place to solder the 470k/470pf and 1M components into brute plated through hole PCB locations with plated through holes for the connecting wires. NOTE: You need to design the input jack board so the face of the jack sticks out a bit farther than the edge of the board so the jacks mount flush/flat against the chassis.

The rest of these little turret boards are for various chassis locations, holding up one end of resistors, those double/triple turret boards I'm mounting near each preamp and power tubes for the heater wires.

Here's my quote for these boards. As you can see price per board varies by quantity of boards ordered and days. I opted for 10 boards, 5 day manufacturing, price $1,029.50 or $102.95 per board. If I was willing to wait 20 days I could have saved $183.80.

Note I opted for a number of upgrades. These boards are quite thick, .125 inch. Lets define that, the thickness of the board plus the thickness of the copper pad plus the thickness of the plating = .125 inch. Just the thickness of the board is about .120 inch.

Its a 2 layer board copper top and bottom. Plated through holes. So you have a pad on the top, bottom, and the hole through the board is also plated creating a very stout soldering point. Most of the board holes are sized for turrets so I'll never had to re-solder them but for the few that are solder pads for components you could re-solder them multiple times. Note I also used plated through holes for all the screw locations that mount the boards to the chassis.

Tab Routing - Here you have to tell the PCB manufacture you want the boards FULLY ROUTED. Tab routing typically leaves tabs of board material connecting all the individual boards. V scoring by the way is more expensive, e.g. where they score the boards with a V and you snap them apart. You won't be snapping boards this thick apart because V scoring still leaves a LOT of material in the middle. So opt for tab routing with no tabs.

Note I opted for LEAD plating. This is the least expensive, but then its not RoHS compliant. I don't care I'm not selling amps. There are however multiple other plating options, including RoHS compliant. The more exotic plating options are more for computer motherboard type boards.

2 OUNCE COPPER - This means 1oz copper on top and 1oz copper on the bottom = 2oz copper total. They literally take 1oz of copper and smash it flat over a board that's where this oz copper stuff comes from. Now I got all chest puffed and ordered 4oz copper once thinking if 2oz was good 4oz would be even more brutish. But it was so thick the manufacture contacted me as the etching process was eating in/under the solder pads so we backed off to 2oz. Just saying.

Note the board material is FR-4 pretty standard fire retardant board material. It is quite strong especially in this thickness. True story, I ordered boards once and they forgot to separate the preamp and power amp boards. I cut them apart with a scroll saw...half way across the 4 inch wide board all the teeth on the scroll saw blade had worn off lol.

Note BLACK solder mask color because black boards are badass! White is a great silkscreen color on the black. But there are other colors. I opted for a blue once, man it was a puke blue/green I didn't care for it. But RED boards with a white silk screen looks pretty good. I almost opted for that on this order.






HOLE SIZE & TOOLING - Try to use standard sized holes and nothing too small or you may have additional charges for odd tooling or tiny holes. Here are all the pad/hole sizes I'm using on the boards. The smallest hole size is .030 but you can likely get away with .020 inch.

PLATED THROUGH HOLES - You need to leave some wiggle room for the plating. Also hole sizes are not accurate to a micron. So for turret holes for example leave a few thousandths of an inch wiggle room for manufacturing variance don't cut it too close. PCB Prime has some how-to info and guidance on this on their website.


----------



## coolidge56

INCH or METRIC...here comes a face palm. So originally I decided to convert to Metric figuring this would be easier than working in inches which is true. But it turns out for PCB boards everything is in mills e.g. inches so they convert back. I don't remember the issues I ran into using metric but I remember doing a giant face palm and starting over on the boards in inches.


----------



## coolidge56

COMPONENT LEAD LENGTH - If you opt for boards this thick you can run into issues where the lead lengths on components, caps, turrets are too short and not long enough to extend through the opposite side of the board. So keep an eye on this when ordering components.

KEYSTONE TURRETS - I'm using 2 different sized turrets, the 1540-4 and 1509-4. Note the .172 inch length of the shank, this is so there's enough of the turret shank sticking out the bottom of the .125 inch thick board for staking. *ALSO Keystone is smoking crack* the TL-5 staking tool does not work on the 1540-4 turret use the TL-8 staking tool. I stake the turrets into the plated through holes, then solder the bottom of the turrets to the board for added BRUTE!


----------



## Exojam

coolidge56 said:


> No my health has taken a nose dive also (censored). You know damn Ford, a 6 cylinder Raptor...REALLY?? Total turn off. I drove one, talk about gutless off the line. I'm driving a 6.7 diesel super duty...wait for it...440hp and 925lbs torque. It will do a burn off at 40mph LMAO!



Well the health part sucks. Trust me, I am still not completely healed up and I have been dealing with possible life ending stuff for over a couple of years now. I am hoping it will be over (for now) in a few more weeks.

I actually just picked up a Ford F-150 sport,4*4 limited edition. The part that killed was getting it setup so the drivers seat would rotate out and down so I can transfer from my wheelchair, and the the hoist to take my wheelchair and put it in the bed. I am loving the truck.

Watch your health man!!!!!


----------



## coolidge56

Exojam I see Fedex is slow as molasses, ETA your location next Monday.


----------



## Exojam

No problem it may be a slow build anyway.

Thank you very much again for sending them over.


----------



## ampmadscientist

Matthews Guitars said:


> It is a fact that there are factors in play where the relative position of components affects performance. There is a somewhat obscure subset of electronics knowledge called "circuit constants" and by adjusting relative component locations you can change the character of the amp. Capacitors and other components close together do exhibit mutual capacitance and mutual inductance as well. You have to be careful with wire dress and routing. Manage wire lengths and how they are routed.
> 
> I've worked on equipment where wire dress was critical to the unit simply OPERATING. You might say that if it was that critical, then the design itself was suspect, but when the wire dress was right, the unit operated to designed specifications reliably and without issue.
> 
> Randall Smith tells tales of spending many hours adjusting component locations and wire dress in prototype amps in order to achieve a certain sound, and when it's achieved, freeze the PC board design so that those distributed capacitances and inductances are reliably replicated in prodution amplifiers.
> 
> If you disagree with the notion that electronic components interact with each other due to their relative positions, then you DON'T know electronics. Inductive and capacitive coupling is very real. And it becomes ever more important as frequencies get higher. At microwave frequencies, it DOMINATES circuit layout.



"It is a fact that there are factors in play where the relative position of components affects performance."

Now here is a guy who is using his smarts. It's a major difference in sound. (and thank you for recognizing the fact)


----------



## ampmadscientist

coolidge56 said:


> Okay lets empower you guys to craft your own boards. First up I use DesignSpark PCB. Its a free download and easy to use. Lets walk through a few important steps.
> 
> 1. Here I have clicked Output/Manufacturing Plots to open this Output Manufacturing Plots popup window. This will generate several files that you need to send to the PCB manufacture so they can manufacture your boards. On the left you see the plot layers I selected for the boards. Everything except the copper paste. To the right on the Output tab note I selected *Gerber*.
> 
> 
> 
> 
> 
> 
> 2. Here is the Layers tab. Note that I selected Board Outline and Top Silkscreen. The board outline will be used to route the boards, just what it sounds like they use a router to separate the individual boards more on that below.
> 
> 
> 
> 
> 
> 
> 3. On the Position tab you see the size of the board 25.35 x 3.5 inches. It adds a .0025 buffer. So one giant board with a bunch of individual boards defined by the board outlines for each.
> 
> 
> 
> 
> 
> 
> 4. Here I zoomed in so you can see what's going on. The green border is the board outline. This will be the outside edge of each board after routing. The red lines are the paths for the router bit. There is .100 inch between all boards, that's the waste material the router bit will remove. So .050 inch spacing either side of the center red lines. The white boarders are part of the white silk screen layer. Technically they are not required on these small boards since its just a printed white boarder but turns out they look pretty cool.
> 
> 
> 
> 
> 
> 
> Its MUCH less expensive to design a single large board with all these multiple boards on it, routed to separate the boards from one another vs having individual boards made say one for the preamp and a 2nd for the power supply.
> 
> GET CREATIVE - I added some additional length to the board and added a bunch of small boards. One for the two guitar input jacks for example, an idea I borrowed from my Marshall Studio SC20H. I used PCB mount cliff jacks. These jacks still attach to the chassis with the classic Marshall chrome nuts so they are chassis mount. But I'm tying the jacks together on a brute .125 inch thick PCB mini board on the back side which makes them even stronger. Plus I have a place to solder the 470k/470pf and 1M components into brute plated through hole PCB locations with plated through holes for the connecting wires. NOTE: You need to design the input jack board so the face of the jack sticks out a bit farther than the edge of the board so the jacks mount flush/flat against the chassis.
> 
> The rest of these little turret boards are for various chassis locations, holding up one end of resistors, those double/triple turret boards I'm mounting near each preamp and power tubes for the heater wires.
> 
> Here's my quote for these boards. As you can see price per board varies by quantity of boards ordered and days. I opted for 10 boards, 5 day manufacturing, price $1,029.50 or $102.95 per board. If I was willing to wait 20 days I could have saved $183.80.
> 
> Note I opted for a number of upgrades. These boards are quite thick, .125 inch. Lets define that, the thickness of the board plus the thickness of the copper pad plus the thickness of the plating = .125 inch. Just the thickness of the board is about .120 inch.
> 
> Its a 2 layer board copper top and bottom. Plated through holes. So you have a pad on the top, bottom, and the hole through the board is also plated creating a very stout soldering point. Most of the board holes are sized for turrets so I'll never had to re-solder them but for the few that are solder pads for components you could re-solder them multiple times. Note I also used plated through holes for all the screw locations that mount the boards to the chassis.
> 
> Tab Routing - Here you have to tell the PCB manufacture you want the boards FULLY ROUTED. Tab routing typically leaves tabs of board material connecting all the individual boards. V scoring by the way is more expensive, e.g. where they score the boards with a V and you snap them apart. You won't be snapping boards this thick apart because V scoring still leaves a LOT of material in the middle. So opt for tab routing with no tabs.
> 
> Note I opted for LEAD plating. This is the least expensive, but then its not RoHS compliant. I don't care I'm not selling amps. There are however multiple other plating options, including RoHS compliant. The more exotic plating options are more for computer motherboard type boards.
> 
> 2 OUNCE COPPER - This means 1oz copper on top and 1oz copper on the bottom = 2oz copper total. They literally take 1oz of copper and smash it flat over a board that's where this oz copper stuff comes from. Now I got all chest puffed and ordered 4oz copper once thinking if 2oz was good 4oz would be even more brutish. But it was so thick the manufacture contacted me as the etching process was eating in/under the solder pads so we backed off to 2oz. Just saying.
> 
> Note the board material is FR-4 pretty standard fire retardant board material. It is quite strong especially in this thickness. True story, I ordered boards once and they forgot to separate the preamp and power amp boards. I cut them apart with a scroll saw...half way across the 4 inch wide board all the teeth on the scroll saw blade had worn off lol.
> 
> Note BLACK solder mask color because black boards are badass! White is a great silkscreen color on the black. But there are other colors. I opted for a blue once, man it was a puke blue/green I didn't care for it. But RED boards with a white silk screen looks pretty good. I almost opted for that on this order.
> 
> 
> 
> 
> 
> 
> HOLE SIZE & TOOLING - Try to use standard sized holes and nothing too small or you may have additional charges for odd tooling or tiny holes. Here are all the pad/hole sizes I'm using on the boards. The smallest hole size is .030 but you can likely get away with .020 inch.
> 
> PLATED THROUGH HOLES - You need to leave some wiggle room for the plating. Also hole sizes are not accurate to a micron. So for turret holes for example leave a few thousandths of an inch wiggle room for manufacturing variance don't cut it too close. PCB Prime has some how-to info and guidance on this on their website.




Did anybody actually build this board and listen to it?
Did it turn out as sounding good?


----------



## Exojam

No one has made one yet.


----------



## MarshallDog

coolidge56 said:


> I purchased my first JCM800 recently the new Studio SC20H. Kind of fell in love with the little 20 watt's tone so for fun I have decided to scratch build a 2204 50 watt.
> 
> The first batch of components arrived lets have a look.
> 
> Mercury Magnetics power transformer P50JM-475.
> Mercury Magnetics output transformer 050JM.
> Mercury Magnetics choke MMC-3H.
> Vishay BC 100,000 hour Polypropylene film filter caps, 5% tolerance.
> Synergy Royal Mustard USA signal caps.
> OHMITE 5W wire wound resistors.
> 
> Film caps continue to shrink in size. I have these drawn on the PCB/turret board and they fit fine.
> 
> 
> 
> 
> 
> 
> Top view
> 
> 
> 
> 
> 
> 
> Side view. The 50 watt power transformer is the same size as a 100 watt.
> 
> 
> 
> 
> 
> 
> Comparing the size of the output transformer, here is a 100 watt on the left vs the 50 watt on the right.
> 
> 
> 
> 
> 
> 
> This will be the first time I have used these Synergy Royal Mustards. Fingers crossed.
> 
> 
> 
> 
> 
> 
> Digi-key misrepresented these TE Connectivity 3W power resistors on their site. I may go with a different brand.
> 
> 
> 
> 
> 
> 
> Next I'll continue work on the CAD for the PCB/turret board.



Hell yeah Bro!!!!


----------



## MarshallDog

coolidge56 said:


> No my health has taken a nose dive also (censored). You know damn Ford, a 6 cylinder Raptor...REALLY?? Total turn off. I drove one, talk about gutless off the line. I'm driving a 6.7 diesel super duty...wait for it...440hp and 925lbs torque. It will do a burn off at 40mph LMAO!



Love those F0RD diesels...nice!


----------



## Exojam

ampmadscientist said:


> Did anybody actually build this board and listen to it?
> Did it turn out as sounding good?



And we were waiting for you to let us know if the capacitor spacing was correct


----------



## ampmadscientist

Exojam said:


> And we were waiting for you to let us know if the capacitor spacing was correct



Capacitor spacing has to be tested.
It will either work good or it will sound like ass.
Put it together and test it.

But I will give you this advice:
if 2 caps are located side by side, one will radiate into the other and vice versa.
That could be a good thing or a bad thing.


----------



## Exojam

I am pretty sure we understand that Amp, you have seen the layout so I gather you would be able to let us know if the cap spacing looks good-bad or what ever.

Is there no formula that can be used taking into account the construction of the cap, the spacing being used etc, that would provide the needed data? How do top shelf amp manufacturers determine this? I do not disagree with the first statement you first made but I think it to much of a blanket one.


----------



## coolidge56

Ah...


----------



## ampmadscientist

coolidge56 said:


> Ah...



Build one and let's hear it.


----------



## Exojam

You have all the information you need so why don’t you build one and fire it and give us your thoughts?


----------



## coolidge56

ampmadscientist said:


> Build one and let's hear it.



We are waiting for you to post pictures of your own build and show Marshall, Metropoulos, and everyone else how they all built theirs wrong.


----------



## South Park

The old school lay out for tube amps works great. It was designed to work with tubes. Tubes have there own set of rules is all you need to know


----------



## coolidge56

Someone received his boards today. Took Fedex long enough geesh!


----------



## Exojam

Thank you Sir.


----------



## Fender

any news ? pics are sadly gone :/


----------



## coolidge56

Fender said:


> any news ? pics are sadly gone :/



Go to this thread https://www.marshallforum.com/threads/82-jcm800-2204-mutilation.113675/


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## Exojam

You will love those XF2’s, well worth the money in my opinion.

If I may ask, how did you test them to find they were so close in specs?


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## coolidge56

Exojam said:


> You will love those XF2’s, well worth the money in my opinion.
> 
> If I may ask, how did you test them to find they were so close in specs?



I picked up a Bias Master recently so I'm able to see the current draw from both in real time. They biased within 1.2mA of each other pretty crazy.


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## Exojam

coolidge56 said:


> Bias Master



You could pull that off with your meter, why the need for that device? 

That device does not seem to me to be able to actually test the tubes in any meaningful way.

Have you by chance looked at the Orange tube tester?


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## coolidge56

Exojam said:


> You could pull that off with your meter, why the need for that device?
> 
> That device does not seem to me to be able to actually test the tubes in any meaningful way.
> 
> Have you by chance looked at the Orange tube tester?



True, until I purchased the JCM900 with it's additional post bias bits of failover, LED's, and junk. There are quite a few threads on how annoying it is trying to bias them so I threw down on the Bias Master. Now all bias jobs are easy peasy.

Also these tubes were from Doug's Tubes and KCA two very trusted sources.

You missed my epic 2020 vintage tube buying meltdown...after purchasing the first two double O getter Mullards I promptly dropped one and broke it like seconds after unpacking it. I got pretty hot under the collar and threw $1,000 down to buy 6 more. lol


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## Exojam

I dropped one myself. That **** sucked.


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