The particularities about Eddie Van Halen plexi 12301

pat_rocks

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It has been confirmed that EVH plexi was stock by many people like Suhr, Friedman and even George metropoulos.

So people began to think that evh had a regular 68' 12000 series and the story ends there. However as you may know about vintage gear, it hapenned that sometimes the guys at marshall's were short on components and used other parts resulting in variations in amplifiers and in tone. this is what supposedely happened to EVH plexi.

Even if EVH plexi is stock, many values have nothing to do with a stock plexi of the 12000 series. Here is a board values of the EVH plexi (in the yellow rectangle) according to pictures of the Suhr Sl68. The major differences with a regular 12000 series have been circled in yellow.

EVH 1959 plexi board.png

This is the "regular" (there had some variations of it) version of the 12000 series :

regular 68 12000.png

The principal mod that was done to this plexi was the replacement of the middle pot by a 50k mid pot instead of the regular 25k : this was confirmed by george metropoulos and Friedman.
Now for the 5000 pf bright cap it is supposed that it was used as some models of sl68 have it and others don't.
the last mod was the use of (sylvania) 6ca7 fat bottle tubes a variation of the el34.

Dave friedman recieved eddies plexi to repair the transformer. He found a stock plexi with the same transformer and rewound the wire on the original one. here is what Dave friedman apparently said in metropoulos forums about eddies plexi :

Post by RACKSYSTEMS » Wed Feb 02, 2011 11:40 pm

Split cathode V1a 250uF/820,V1b .68/820
All coupling caps are 0.022uF,Bright channel coupling cap is 0.0022uF

470k mixer resistors
500pf [red out of 69 amp] mixer bypass cap
Bypass cap on V2a is .68uF and a 220uf to 470uf
33k/560pF lemco tone stack combo
100k NFB resistor at 4 ohm tap
220k bias splitter resistors
0.1 uF cap on presence control
.022uf output couplers

filtering is
2] 100uf's f&t in series mains
2] 32uf's f&t in series screens
1]100uf lcr phase inverter
1] dual 33 x 33 f&t preamp

It is interesting to see how variations of components even in a stock plexi could change the tone of an amplifier. Little accidents like shortage of components made those variations happen sometimes in the past. What is more funny it is that one of these ended up in the hands of a great guitar player. Just imagine the probabilites of it happening... crazy !

EDIT : Now there is still a possibility that eddie plexi had jose arredondo mods and that they influenced his signature tone and that those mods were removed when the amp went to the technicians. Yeah eddie knew a lot about gear. Steve Vai and Pete thorn seem to allude that perhaps josé had something to do with eddies plexi in this video :



Why am i posting this here ? To share but there is also a hope that Marshall will begin to do what prs did with hendrix and their HDRX 20. Recreating the tone of an icon of rock and making it available in a small size box. They reversed engeneer the transformers and made a 20watt version of it to miniaturize the tone. Finally they added a master volume on a plexi !!!

Now let's imagine that marshall made a 20 watt plexi called the SL78 (reference to evh first album) with those values above, a 50k mid pot, a PPIMV master volume, fx loop and finally they reduced the size compared to the sv20... Well they would sell many...
 
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pat_rocks

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That Prs HDRX20 is it?, it gets some nice reviews, I haven’t heard one in person yet. Medium gain amp isn’t it?

I’ve been a Hendrix fan for a long time, longer than some of you have been alive, lol. But his tone was never a tone I’d want to try to emulate.

The man was a genus on a guitar fretboard, but his tone was never anything to write home about., imo.

Just my :2c:
I think they are just milking Hendrix's name and they went to the extreme as to duplicate the amp and miniaturize it. Well they are milking plexi amps because marshall wont do it the right way anyway haha... A real tube plexi with a miniaturised real copy of a transformer, a master volume for low bedroom volumes, a fx loop all of this in small size... Even I who prefer to build my own amps want to buy one xd...
 

Matthews Guitars

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So far I have not heard a demo of the PRS HDRX amp that impressed me. Maybe it's the demo, but I'm not hearing the magic. Something's missing.

In truth I have yet to hear a PRS amp that I actually would prefer over other available amps.
 

scozz

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I think they are just milking Hendrix's name and they went to the extreme as to dublicate the amp and miniaturize it. Well they are milking plexi amps because marshall wont do it the right way anyway haha...
Some how my post got messed up, I went to edit a misspelling and,…. well I don’t know?
 

pat_rocks

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I'm writting this thread because EVH is probably the ultimate reference tone for a plexi. After a plexi the best tone would be the tone of a peavey 5150 particulary the tone of Dann Huff :
the most underrated guitar player which was unfortunately born at the wrong time...
 
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playloud

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The details of 12301's circuit conflict in the various accounts. It may just be that different people saw the amp at different times, and parts were replaced over time (was that 50k pot there on the earlier VH albums?)

There was a thread earlier this year which discussed this: https://marshallforum.com/threads/definitive-12xxx-series-evh-spec-warning-long-post.125064/

For that matter, I don't think there's a definitive "12000 series" spec, so almost any example you care to find can be viewed as a "variation", relatively speaking. In that sense, I think the probability you ask us to imagine is actually quite high!

It's also not clear to me why the Suhr SL68 is being used as a benchmark. Was this claimed to be an exact replica of EVH's amp? If so, I'm surprised by the filtering (for a start).
 

pat_rocks

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The details of 12301's circuit conflict in the various accounts. It may just be that different people saw the amp at different times, and parts were replaced over time (was that 50k pot there on the earlier VH albums?)

There was a thread earlier this year which discussed this: https://marshallforum.com/threads/definitive-12xxx-series-evh-spec-warning-long-post.125064/

For that matter, I don't think there's a definitive "12000 series" spec, so almost any example you care to find can be viewed as a "variation", relatively speaking. In that sense, I think the probability you ask us to imagine is actually quite high!

It's also not clear to me why the Suhr SL68 is being used as a benchmark. Was this claimed to be an exact replica of EVH's amp? If so, I'm surprised by the filtering (for a start).
We can assume it is the case, as Suhr was one the guys who spent most of the time Eddies plex. I believe it is the stock plexi minus the josé arredondo mods. Those mods certainly were one of the reasons it sounded like it did. When you look at the guts of a bray coco you'll see that they are pretty close to the suhr sl68 and no one matches EVH tone like David Bray amps does :
 

blues

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It has been confirmed that EVH plexi was stock by many people like Suhr, Friedman and even George metropoulos.

So people began to think that evh had a regular 68' 12000 series and the story ends there. However as you may know about vintage gear, it hapenned that sometimes the guys at marshall's were short on components and used other parts resulting in variations in amplifiers and in tone. this is what supposedely happened to EVH plexi.

Even if EVH plexi is stock, many values have nothing to do with a stock plexi of the 12000 series. Here is a board values of the EVH plexi (in the yellow rectangle) according to pictures of the Suhr Sl68. The major differences with a regular 12000 series have been circled in yellow.

View attachment 119716

This is the "regular" (there had some variations of it) version of the 12000 series :

View attachment 119712

The principal mod that was done to this plexi was the replacement of the middle pot by a 50k mid pot instead of the regular 25k : this was confirmed by george metropoulos and Friedman.
Now for the 5000 pf bright cap it is supposed that it was used as some models of sl68 have it and others don't.
the last mod was the use of (sylvania) 6ca7 fat bottle tubes a variation of the el34.

It is interesting to see how variations of components even in a stock plexi could change the tone of an amplifier. Little accidents like shortage of components made those variations happen sometimes in the past. What is more funny it is that one of these ended up in the hands of a great guitar player. Just imagine the probabilites of it happening... crazy !

Why am i posting this here ? To share but there is also a hope that Marshall will begin to do what prs did with hendrix and their HDRX 20. Recreating the tone of an icon of rock and making it available in a small size box. They reversed engeneer the transformers and made a 20watt version of it to miniaturize the tone. Finally they added a master volume on a plexi !!!

Now let's imagine that marshall made a 20 watt plexi called the SL78 (reference to evh first album) with those values above, a 50k mid pot, a PPIMV master volume, fx loop and finally they reduced the size compared to the sv20... Well they would sell many...

When the Plexi Palace forum was still active Terry Kilgore (tube tramp) knew EVH well

He said his amp was a particularly good sounding stock Marshall.

At one point one of the transformers blew. It was replaced with one from a1971 Marshall.

He said he was there when it blew. The story goes that
the amp blew a fuse. Evh tried to use tin foil to replace the fuse. It did not work out.
 

pat_rocks

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When the Plexi Palace forum was still active Terry Kilgore (tube tramp) knew EVH well

He said his amp was a particularly good sounding stock Marshall.

At one point one of the transformers blew. It was replaced with one from a1971 Marshall.

He said he was there when it blew. The story goes that
the amp blew a fuse. Evh tried to use tin foil to replace the fuse. It did not work out.
Check david bray amps in the video i posted. Inspect the guts of those amps and you'll see the answers. I believe he is the only one to have cracked completely the code.
 

playloud

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We can assume it is the case, as Suhr was one the guys who spent most of the time Eddies plex. I believe it is the stock plexi minus the josé arredondo mods. Those mods certainly were one of the reasons it sounded like it did. When you look at the guts of a bray coco you'll see that they are pretty close to the suhr sl68 and no one matches EVH tone like David Bray amps does :


I'm not questioning whether David Bray or John Suhr make great amps - I'm sure they both do - or whether they get close to EVH's tone (ditto), but I think we're talking about different things here.

Being able to emulate a tone on record doesn't mean whatever amp you used to do so has an identical circuit. In fact, we can already rule that out here, because the SL68 uses high filtering and the Coco 50 is 50W.

Listening to those videos, I think you can get similar results with any split cathode lead circuit, Greenbacks and a high-output humbucker.
 

pat_rocks

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I'm not questioning whether David Bray or John Suhr make great amps - I'm sure they both do - or whether they get close to EVH's tone (ditto), but I think we're talking about different things here.

Being able to emulate a tone on record doesn't mean whatever amp you used to do so has an identical circuit. In fact, we can already rule that out here, because the SL68 uses high filtering and the Coco 50 is 50W.

Listening to those videos, I think you can get similar results with any split cathode lead circuit, Greenbacks and a high-output humbucker.
On this point i believe you are right. However if we remove the power amp and only talk about the preamp part of the board it should be extremely close. But i agree a 50watt amp is clearly different as a 100w amp particulary about the power amp section. The filter caps, transformers etc... Those are also extremely important.
 

Maxbrothman

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Step down from E matters in how a cranked Plexi sounds.

EVH-isolated guitar tracks will sound like stock Plexi + Flanger/Phaser + EVH pickups. That's the sauce to get his sound for Panama and Ain't Talkin.

You will also have to play like him to get there.



If you remove the flanger, you can hear the Plexi. Here is a solo from Hot for Teacher. You can hear what sounds like a Plexi.



Studio mixing brings it all out. Anyway, his playing is incredible, and with his pickups, you can get there with a stock Plexi.
 

ELS

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Are there actual pictures of the amp circuit? not doubting what is said about the amp I just enjoy analyzing amp layouts and circuits

btw the 820 ohm cathode resistors in EVH's plexi had drifted up to around 1.1k for all of them
 
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FleshOnGear

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The EVH tone didn't come from minor differences in the amp circuit. You can use a wide variety of 4 hole NMV amps to get the tone IF you have the other bigger parts correct.
I tend to agree with this. Just my humble, non-EVH-tone-chaser opinion. I think the technique, pickups, variac, and JBLs are more consequential than a few components in the amp. Not saying those components have no effect.
 

pat_rocks

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Are there actual pictures of the amp circuit? not doubting what is said about the amp I just enjoy analyzing amp layouts and circuits

btw the 820 ohm cathode resistors in EVH's plexi had drifted up to around 1.1k for all of them
I think it is the only one we got. It was supposedely taken during a past restoration of the amp. However i have my doubts about the picture like the missing tube socket and many capacitors seeming to be not stock, but who knows if marshall was out of stock of mullard caps and used whatever they found ? :

supposedly eds plexi.jpg
however despite not looking legit at the first look, the components mentionned by friedman are there. The big cap on v1 is a .68 phillips chiclet cap. and the black cap seems to be what he has been refering to as the 220-470uf cap. There are some .022 brown drops. The big blue cap is supposedely a 32+32 or a 16+16 uf cap.

here is a variation with it :

EVH 6v6 plexi board.png

i just found a picture of a 100w 68-69 sl and the chiclet phillips capacitors seemed to have been used at marshalls :

chiclet.png
 
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