EVH Chassis Layout

[Loganp]

I am not sure anyone has seen these pics.. maybe someone has but i figured i would post them.

http://www.customaudioelectronics.com/evh_photo_02.htm

second set down. ( can you guess witch one is his magic marshall )

question: in the first pic of eddie's rig there is a box that has a cable running to it right in the middle of the pic it is sitting on top has 2 dials and a red light. now i have also seen it in jame's rig from metallica.

anyone have an idea on what this is. it is driving me nuts.

[RACKSYSTEMS]

Its a peterson strob tuner and none of those marshalls is the one at this time he was leaving it a home. I have worked on about half of those amps though. Dave Friedman

[JamesHealey]

1.1k sounds fatter, warmer and like the solo from Ice Cream Man to me really smooth and EVH like, but i'd have to say 820ohm has more crunch/cut/slice and plays easier.

gainer? well thats debatable I dont think theres much in the gain but it sure sounds/feels different.

[JamesHealey]

if you compare 10k to 820ohm you can deffinatly tell upping the value here is reducing the gain thus making it fatter and warmer as rockstah said, I also asked a tech locally and he explained this to me and verified this.

The more I listen to evh, im not sold on the shared cathode arrangement people in this thread claim to have seen or the 56/250 tone stack.

Mark Cameron claims to have seen split cathode and I agree with him here, ****** I do not trust one bit although he makes a mean OPT, im sure someone here said he'd never even seen the amp he was just going on someone elses eye witness account.

Im sold on the fact it was a stock amp but a little bit more toward lead specs than bass.

[Mr. Beasty]

I personnaly like 820k the best. 820k is pushing a different part of the spectrum and gives the perception of more gain, IMO.

Mark Cameron claims to have seen split cathode and I agree with him here, ****** I do not trust one bit although he makes a mean OPT, im sure someone here said he'd never even seen the amp he was just going on someone elses eye witness account.

To Chris Merrem's defence, he may have seen another amp than #1 ... I think it is pretty clear now that Ed was using at least two Marshall heads to create his tone, perhaps the second one had shared cathode?

[gluke]

Hi guys,

There is a guy in Norway who owns serial number 12304 and he was kind enough to post pics in this tread (scroll down to see the pics):

http://forum.gitarnorge.no/Marshall-Ple ... 0&start=20

[gluke]

Ok you might have to be a member to view the pics. I got them so if anybody wants them or have a way to post them here send me a PM and I'll send you the pictures.

[jp0971]

that guy posted them here as well fwiw

http://forum.metroamp.com/viewtopic.php?f=3&t=22562" onclick="window.open(this.href);return false;

[gluke]

Ok didn't know that. If this is 12304 SB and Ed's 12301 is a super lead, what would be the difference at that time?

[jp0971]

i'm not sure if this was mentioned before, because i can't find the answer...

http://i70.photobucket.com/albums/i87/B ... 9ede_b.jpg" onclick="window.open(this.href);return false;

(big picture)

That choke looks more like a 70's choke doesn't it? any thoughts on that?

[daneswede]

As I pointed out on that post at PlexiPalace, I'm 99% sure that ****** also posted once that he saw that amp a little later and it had been converted to split cathodes on V1. I thought the John Suhr thread at Gear Page or wherever detailed split cathodes whenever John saw it.

Do you ever wonder if, like so many things Eddie doesn't like 'fessing up about, there is not just one "magic" Marshall? The differences in accounts of sightings almost make it seem as if there was the original amp, and then he found at least one more that he liked as well and used too, but he'll never tell?

i AGREE, tHERE ARE SEVERAL PICTURES (pROBABLY due to the self admiton of ED himself ) that he blew up many a trannie ) ...that he would use late 1970s i.e 1977 100 watters and 178 10 watters on tour AND his beloved 68 12000 too of course. In the Van Halen books Youl see many a picture of this happening on tour .


Im sure his cat in the cradle was his beloved 68 12000

[michaiel]

I know this has been beaten like a dead cat, but after searching this forum for awhile collecting notes, it seemed simpler to just ask again....
Does anyone have a definitive schematic or computer graphic of the original amp. Mighty Mike and Billy Batz I think have both created some in photoshop or similiar program, but the links I found are dead. I am thinking about ordering George's kit and building. If anyone has any words of wisdom on parts to order with it please feel free to chime in.
thanks

[michaiel]

just found George's link.....http://forum.metroamp.com/viewtopic.php?t=9972" onclick="window.open(this.href);return false;. If anyone wants to add to this please feel free...

[leadguy]

Originally Eddie's 12301 white knob Plexi circuit was basically the same as this Plexi 12267, 34 serial numbers away http://vintageamps.com/plexiboard/viewt ... 2530b897f3" onclick="window.open(this.href);return false;

Split cathode V1a 250uF/820,V1b .68/820
All coupling caps are 0.022uF,Bright channel coupling cap is 0.0022uF
bright cap on vol pot 0,005uF
470k mixer resistors
470pF mixer bypass cap
Bypass cap on V2a is .68uF
33k/556pF tone stack combo
47k NFB resistor at 4 ohm tap
220k bias splitter resistors
0.1 uF cap on presence control

This is a Marshall 1230x circuit (Tazin) which is a Super Lead serial number 12305 which is only four digits away from Ed's amp and can be found here in the 1230x section http://forum.metroamp.com/viewtopic.php?f=25&t=9680" onclick="window.open(this.href);return false;

Post by Tazin

"If you look in the Marshall Schematics forum under the 1959 100 watt Marshall (several version) thread you'll see a schematic labeled as 1230x. This is a schematic I drew a while ago for Super Lead SL/12305 which is only four digits away from Ed's amp. Anyone who has investigated Marshall amps of this era knows that serial numbers don't necessarily mean that the amps where mfg'd consecutively with regards to serial numbers, but I will say that amp SL/12305 did seem to share the same top mounted phase inverter cap (HUNTS 50uF+50uF/450v) and the same 0.68uF/100v yellow WIMA caps which Ed's amp reputedly has. Amp SL/12267 has the same split cathode circuit but runs slightly different components. This amp originally had the single element HUNTS 50uF/500v for the phase inverter filter cap (now changed to an LCR 50uF+50uF), and has the mustard 0.68/160v bypass caps for the pre-amp."

Eddies original circuit has much more mids and upper mids and would be brighter than many other Plexi circuits.
The addition of a 470uf or 330uf capacitor on V2's cathode would bring down the brightness and produce more low end.

VH1 is generally considered to be on the bright side as opposed to later albums, even by Eddie himself.

The mods.

The stock .68uf capacitor on V2a was paralleled with a 470uf capacitor at some point and then both the .68uf and 470uf capacitors were replaced by a single 330uf capacitor. The timeline of when these mods were done is not known.

It also has filtering of that era and a slight change in the feedback circuit.
The NFB resistor at the 4 ohm tap is 100k and not 47k.

By the time of the staged VH11 publicity studio photographs, the output Transformer had been changed from a stock 12 series Dagnall 1.5 inch to what seems to be a Drake 2 inch and the open ended choke had been changed to a end bells choke. In the early 90s, the output transformer was changed again by Steve Fryette and then by John Suhr.

John Suhr says this

“The only change, besides the minor tweaks when I saw it, was the VHT transformer [Steve Fryette, founder and former owner of VHT, worked on the head at one point and replaced the output transformer]. My job was to replace that transformer with a donor from another plexi with a similar circuit and close serial number that belonged to Matt [Bruck, Ed's former tech and now assistant].

Steve Fryette says this

"I might add, and this is just from memory, but I recall that the circuit was actually closer to a 70 JMP than it was to a plexi, something I attributed to this possibly being a transition model, seeing as how it had a plexi panel, but apparently the newer input (ie split cathode) and feedback configuration."

and this

"All that aside, Matt insisted that something needed to be done so I gave it a complete once-over and I then took the liberty of installing a Pittbull Classic output transformer into it to see if anyone would notice."

and then after John Suhr the amp went to Peter Van Wheelden that was also mentioned by Ed in an interview

John Suhr says

"After me [the amp] went to Europe [presumably to Peter Van Wheelden, documented in an old issue of one the guitar mags]and everything was rewired and became a mess he [Ed? Matt?] wasn’t happy with. I believe Dave [Friedman] has the amp right now and is trying to breath life back in to it…."

So the amp goes to Steve Fryette who replaced the output transformer and then to John Suhr who did the same thing and then to Peter Van Wheelden.

David Friedman

Jeez the pic was taken some how after I got my hands on it. This is the state it is in now. V1 820/.68 v2 820 330uf. Originally v2 .68 and 470uf supposedly. Stop all this silly stuff it was a stock 12 series amp with 2 changes the 470uf on v2 with a .68. Filtering of that era and a slight change in the feedback circuit. I won't say anymore. Remember you are trying to recreate a recorded tone. Its not how the amp sounded in the room period. Add the signal chain and the bias turned all the way hot and then dropped with the variac and also remember it had a latter jmp output transformer and choke installed at some point.

Guys I have the amp I know this was the same amp John suhr saw. Just at some point in the 90's some caps were Changed and the wire is teflon now. Peter did the rewire as I was told. Ed only use one marshall for all the recordings and it was this amp. Another amp he likes is the wood 100 watt you see in many pictures. I have worked on that also. It was completely stock except for the 100k 4ohm feedback. All the Jmp's that he own from that time also are stock with the 4ohm 100k feedback. All amps had 6ca7s and were Biased all the way hot and then dropped with a variac. Most had a .68 on v2 accept the main plexi. Thats all there is to it other then the effects in front. All the other amps had a 2.7 k on v1.

============================================

From various postings by John Suhr and Dave Friedman who saw the white knob Plexi around the early 1990s and after.

============================================

John Suhr

All solder joints were original up to the treble pot except for a more bass mod which was a 470uf + .68uf on the V2 cathode which was later changed to just a 330uf capacitor, so there was no cascade.
There was also a minor change in the feedback circuit as well.

The screen resistors and the wires to the output transformer and the power supply capacitors were not original solder joints.

===========================================

Dave Friedman

Split cathode V1a 250uF/820,V1b .68/820
All coupling caps are 0.022uF,Bright channel coupling cap is 0.0022uF
bright cap on vol pot 0,005uF
470k mixer resistors
500pF mixer bypass cap
Bypass cap on V2a is .68uF and a 220uf to 470uf
33k/500pF tone stack combo
100k NFB resistor at 4 ohm tap
220k bias splitter resistors
0.1 uF cap on presence control
.022uf output couplers

Here is the spec for the tone. Now this spec depends on the amp and might not sound right. Very important you also have to bias the amp to like around 80ma at normal wall voltage and then drop the amp to 90volts with a variac. You must have the 6ca7s for the tone and there ability to hold up to this abuse. But everything matters in the tone kind of wire in the amp caps transformer etc.

Look I have been inside of many of Eds amps they are all for the most part stock Marshalls with minor changes

Bias the amp to 80 ma with out the variac. Then just use the variac at 90. The bias lies where it lies.

================================================

Ed only use one marshall for all the recordings and it was this amp. Another amp he likes is the wood 100 watt you see in many pictures. I have worked on that also. It was completely stock except for the 100k 4ohm feedback. All the Jmp's that he own from that time also are stock with the 4ohm 100k feedback. All amps had 6ca7s and were Biased all the way hot and then dropped with a variac. Most had a .68 on v2 accept the main plexi. Thats all there is to it other then the effects in front. All the other amps had a 2.7 k on v1.

================================================

Looks like Ed has a Drake 2 inch output transformer from around mid 1967 and a Choke maybe from the early 70s in the VHII 1978 studio photos. Bit of a FrankenAmp.

Ed's transformers and choke



Original 12 series 1.5 inch transformers (Dagnall C1998 output transformer)



A Germino Fillmore 100 with a Drake 1202-132 2 inch output transformer (****** clone) http://www.germinoamps.com/fillmore100.htm" onclick="window.open(this.href);return false;

Drake 1202-119 2" core 1.75k primary impedance 8,16 and 100V taps

Drake 1202-132 2" core 1.75k primary impedance 4,8,16 taps

They are both basically the same except the 1202-132 has a 4 ohm tap instead of the 100V tap.



Ed's choke



Transformer timeline

11/65 1202-84 2" core 4K primary 8,16 and 100V taps


02/67 1202-119 2" core 1.75k primary 8,16 and 100V taps


06/67 1202-132 2" core 1.75k primary 4,8,16 taps


Also, the Dagnall C1998 seems to date to 11/67.

Rough Marshall transformer timeline

- '66 to february/early '67: 4xKT66, 1202-84 OT, 1204-43 PT, 560VDC. JTM45 front panel.

- february '67 to mid '67: 4xEL34, dual rectifier, 1203-80 PT, 1202-119 OT, 490VDC. Black flag JTM panel.

- mid '67 to late '67/early '68: 4XEL34, 1203-80 PT, 1202-132 OT. First JMP panels.

- late '67/early '68 onwards: 4xEL34, 1203-80 or T2562 PT, Dagnall C1998 OT. JMP panels.

In between these there were all sorts of transitional "bastard" amps...like JMP panel amps with typical "black flag" circuit and transformers. or the very rare early, early EL34 amps which still had the 1204-43 PT with 560VDC and JTM45/100 chassis and front panel.

[stusixtysix]

leadguy - interesting that combo of 47k/ 4 Ohm NFB. never seen that one posted before. Would be pretty gainy. I have a '73 50W with 100k 4Ohm and its all grind all the time, however it's treblier because of the 2k7 /0.68 up front. It's due for a cap job, while its on the bench I might try bodging these specs into her and see what comes out the other end