Finally…Plexi 100W in collection (paging the experts)

shakti

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BTW, after I reformed the original Radiospares mains filter caps, and did it correctly this time, it does seem to sound a little better and with less ghosting. Still undecided if it sounds as good and has as little ghosting as it did with the Sozo Royals, but at least reforming was 100% successful. They passed ESR and capacitance tests with flying colours and the voltage drop came down to less than 0.5V, so they seem to be perfectly fine. That’s pretty amazing for 55 year old caps. Say what you will - those old caps seem to have been made very well.
 

Chappy

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Maybe some members here with a lot of free time on their hands (retired) could search through all of Tazin's comments and create a sticky thread here in the Workbench forum. It could be broken down into different topics, with either cut and past quotes or links to the original threads. The guys over at Audiokarma did something similar with one of their contributors.


Just thinkin out loud

Steve
 

Matthews Guitars

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I've seen not less than three or four different font variations just in the metal panel 1959 panel type alone. Some are unique to reissue panel types. When I design reproduction panels I have to figure out what the original font was, usually using photographs and such tools as the Font Squirrel to find the best matches. Even then, it doesn't always get everything right.

I'm 99 percent sure that the Humanist font is right for most original plexi panels. The distinctive way the capital M is built is the single strongest indicator that it's Humanist.

And now I know that Futura is a font that should be in my list to review as well.

I can't reasonably make every possible variation of every possible panel. Imagine how complex the task would be if I offered four variants of the standard JMP 1959 front panel in plexiglas, those four variants being four different fonts. I offer the plexi panels in the Humanist font that I believe to be correct for original Plexi panel amps, and I offer the metal panels in the fonts that I matched up from original metal panels...whatever that is. I don't remember.
 
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neikeel

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I've seen not less than three or four different font variations just in the metal panel 1959 panel type alone. Some are unique to reissue panel types. When I design reproduction panels I have to figure out what the original font was, usually using photographs and such tools as the Font Squirrel to find the best matches. Even then, it doesn't always get everything right.

I'm 99 percent sure that the Humanist font is right for most original plexi panels.
And now I know that Futura is a font that should be in my list to review as well.
I can't reasonably make every possible variation of every possible panel.
I offer the plexi panels in the Humanist font that I believe to be correct for original Plexi panel amps, and I offer the metal panels in the fonts that I matched up from original metal panels...whatever that is. I don't remember.

How’s production and shipping going with those? I hope the originals I sent were useful in matching the fonts, different colours and backing?
 

TAZIN

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Yeah, that's understandable. What about a website then? :)
I thought about a web site but it would become too cumbersome with all the notes & photos I have.

Maybe some members here with a lot of free time on their hands (retired) could search through all of Tazin's comments and create a sticky thread here in the Workbench forum. It could be broken down into different topics, with either cut and past quotes or links to the original threads. The guys over at Audiokarma did something similar with one of their contributors.
You guys are giving me way more credit than I deserve. A lot of the info I present is just rehashed stuff from others that I've accumulated over the years. There are others here like neikeel, NedB, London John, just to name a few, that have a vastly superior knowledge about early Marshall's then I ever will.
 

TAZIN

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I've seen not less than three or four different font variations just in the metal panel 1959 panel type alone. Some are unique to reissue panel types. When I design reproduction panels I have to figure out what the original font was, usually using photographs and such tools as the Font Squirrel to find the best matches. Even then, it doesn't always get everything right.

I'm 99 percent sure that the Humanist font is right for most original plexi panels. The distinctive way the capital M is built is the single strongest indicator that it's Humanist.

And now I know that Futura is a font that should be in my list to review as well.

I can't reasonably make every possible variation of every possible panel. Imagine how complex the task would be if I offered four variants of the standard JMP 1959 front panel in plexiglas, those four variants being four different fonts. I offer the plexi panels in the Humanist font that I believe to be correct for original Plexi panel amps, and I offer the metal panels in the fonts that I matched up from original metal panels...whatever that is. I don't remember.
The majority of the JMP era front plexi panels used Monotype's Gill Sans font. Bitstream's Humanist 521 is a copy/knockoff version.
 

Matthews Guitars

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Ah, that's good information. Now that I know that, I'll switch to the correct font for future production. I've already installed all versions in Adobe Illustrator. Thank you.

My quest is to always get closer and closer to true authenticity. To make panels that can be taken by experts as being true new old stock originals in perfect condition is the goal. (Except I mark them as my product, around a knob hole, where it will never be seen when installed.)
 

Derrick111

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I thought about a web site but it would become too cumbersome with all the notes & photos I have.


You guys are giving me way more credit than I deserve. A lot of the info I present is just rehashed stuff from others that I've accumulated over the years. There are others here like neikeel, NedB, London John, just to name a few, that have a vastly superior knowledge about early Marshall's then I ever will.
Well, the four of you could make this a group effort making this a much, much easier task 😉 In all seriousness, it would really be a shame for this data to be lost. As we've seen with the Plexi Palace, a forum cannot be relied upon to be the keeper either. Thank about the wealth of info that vaporized when that plug was pulled 😢 Plus, the context of a lot of data found in threads is presented in a manner that often just leaves more questions unlike a book.

@neikeel @London John @Ned B
 

shakti

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I’ve now had (near) total success with reforming the original Radiospares filter caps in this amp. I did them stage by stage so I could really pinpoint if there was a problem somewhere, but both the mains caps and screen caps reformed to less than 0.5V drop across a 100k resistor, so they obviously have very little leakage. The phase inverter cap (single 32 uF) was a little harder to get within spec, but several rounds of several hours per day gradually got it down to about 6V loss. I’ve heard some people say you should get it to less than 2V for it to be OK, but I’ve also read that less than 10% of applied voltage is OK (seems very high though). At this point it was getting hit with 500V+ which was also well outside its rated voltage so I decided to quit there and test again.

The amp sounds even better now, nary a hint of ghosting at all, nice and tight but very warm and no noise. So it does look good for these caps. Next up will be tube tweaking. But already now it sounds fantastic with the tall bottom G12H cab and scary close to the Voodoo Child (Slight Return) and other Electric Ladyland tones.

Now it would be great to complete the restoration with a blue Hunts 8uF for the bias circuit. Also I would guess it had a Radiospares 32+32 axial for the preamp where I now have a NOS Erie. If anyone has some of these caps and would be willing to sell I would be very grateful.

Lastly, I’m looking for the end caps for the control knobs, which are all missing. I think I’ve seen people selling them. I have a set of the Scott knobs that Valvestorm used to sell (now sold out) but they’re earmarked for a planned build and this amp has the original knobs, just missing the caps.
 
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Derrick111

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But already now it sounds fantastic with the tall bottom G12H cab and scary close to the Voodoo Child (Slight Return) and other Electric Ladyland tones.
Wasn't VC recorded on a Dual Showman? 😉 I hope you find the parts you need to restore this baby to perfection. Sounds like it's on it's way!
 

shakti

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So they say, but it doesn’t sound like that to
me. Voodoo Chile (the blues jam) sounds like a Fender amp to me, but Sligtt Return sounds like a Marshall to my ears. Would love to see photos. Isn’t there supposed to be film from the recording of the latter?
 

Derrick111

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I wish
So they say, but it doesn’t sound like that to
me. Voodoo Chile (the blues jam) sounds like a Fender amp to me, but Sligtt Return sounds like a Marshall to my ears. Would love to see photos. Isn’t there supposed to be film from the recording of the latter?
I wish there was film, that would be magnificent! It doesn't sound like it to me either, Sakti... I agree with Marshall, and I was posting a bit "tongue and cheek".
 

shakti

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I made a couple of quick clips for your pleasure…or so I hope. At least you might hear how it sounds. One with a Les Paul and one with a Strat and fuzz. Alex Attenuator at -9dB into the tall bottom on the left with 25W T1281s.



 

playloud

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Incredible sound! I like to think the coiled cable is also doing some work here, not to mention that wailin' vibrato. Are you wearing flares too?
 

shakti

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No flares, just regular jeans and comfy slippers. I like to think they contribute to the velvety tone. 😁

I nearly always use a coiled cable when going straight into the amp, at least Marshalls. For amps set entirely clean I like a lower capacitance cable but the higher capacitance of the coiled is crucial for overdriven Marshall sounds.
 

neikeel

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Sounds fabulous- spot on.

Hmmm. I’ve not had a coily cable for years!
 

AndyD

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What a sound! Both videos were spot on. They are both what I understand people referring to as "grail tone". Fabulous!
 

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