Debate on Eddie's Plexi

[Darden]

Yowza. 51 pages over there.

[Type O Neg]

I dont normally post on the forums. I have been following the EVH and this thread since the beginning.
I am running a JCM/ Peavey VTM style amp configured closely to a cascaded amp ala RR or SDM. 1st stage 2k7 .68uF .022 coupling. 2nd stage .0022 w/ 820 .68uF, 220k plate configured like the Jose schematic and the forum discussion.
3rd gain stage with the .68 and 470Uf as Dave mentioned previously in the thread.
Reconfigured the feedback and phase inverter input cap .1 like a bass amp.
Dimed all eq and backed the presence down to around 8, still in ahh of the sound of this configuration not overly gainy as one would expect playing thru a weber green back loaded cab. Playing style and dynamics have a lot to do with the sound.
It really goes a long way when Dave or John share info and their expertise with the forum. Thanks!!!

[vh junkie]

BTW,
What is that yellow, square .68 on the pic ofEed's amp. Is that an old Wima?

If you believe these guys, its on of these:
http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 0413553810

EDIT: Well, this morning there were 5 available @ $3... I bought 3 just FTH of it... looks like someone else grabbed the other two... now they are $3.50 each!

I shoulda known!

[vanhalen5150]

When you chum the waters the sharks tend to show up.........

[vanhalen5150]

Yowza. 51 pages over there.

I tried to start back where I had left off last week at about page 10. It's painfull.

[vh junkie]

Helloooooo McFly ? what part of the explanation involving the output transformer being replaced and the choke being replaced does not register ? You guys are bantering about the innards of a stock circuit , but neglect the impact of massive voltage altering effects let alone magnetic effects on the tone hence the changed otx & choke . I spoon fed this obvious elephant to you all years ago , still . still you walk right past it

Now Biff.... Just kidding!
Been meaning to ask you to expound on this.

[leadguy]

if you walk through the lineage of this amp being from the Rose Palace (which would have worked it hard on the weekends and during events if they had a rock band like Zep in town) it pretty much makes some sense .

a) Rose Palace modest play time , but may have been exposed to abuse if it was in a practice hall situation . If so it was exposed to abuse and repairs . As you get into the 73 era the 12 series couldn't keep up with a metal panel volume wise or balls wise . So maybe then it was worn or had high expense from service . And was sold

b) I believe Ed got the amp with the origional transformers . Mainly because he said Jose beefed up his amps . He was right . Because he blew up the origional ot in his experiments and went to Jose , right down the road . Here Jose put in a JMP output . Much lower impedence , physically larger and would absolutly define 'beefing up ' a 12 series 100 watter . It would be much louder and ballsier . A 12 series is more like a loud 50 watt plexi rather than a Metal Panel 100 watter or Ali chassis 100 .

c) from his relationship with Jose , the head evolved into basically a master volume JMP .

d) not too far off of an amp for VHII and the similarity with the live tone . When the VHII tour came out his live tone was still very stellar . Those JMP head were VERY similar to what his main head turned out to be !

Right down to the American shipped JMP's with 6550's . GE 6550's which were the closet tube to a Sylvania 6CA7 in tone and ruggedness . The mod to do so ? Beef up the bias and take the feed back from the 4 ohm tap instead of the 8 ohm tap . Sound Familiar ?

So on a final note . When is the earliest picture of Ed with the #1 and is it woodie ?

Here is an early pic from a backyard party in 1976.

VH_-_1976_77_.jpg

Is this the woodie head or his favorite white plexi he has always pined after ?

So are they bare ( tolex stripped ) or white with a black Marshall logo ?

or is this 1976 Starwood gig have # 1 ?

1195.jpg

My take is he was really impressed with what Jose gave him back upon a blown otx . A much bigger , louder mother of an amp . So he tried to help Jose ( a likeable old immigrant gentleman like himself ) and he believed Jose did great work .

Good points there.

http://forum.metroamp.com/viewtopic.php?f=16&t=32406" onclick="window.open(this.href);return false;

[Bore Em at the Forum]

I remember from 1982 (maybe Guitar Player interview about Diver Down?).....or Musician from summer prior....

Ed talking about his favorite tone being his Fender Bandmaster in his room.

Anyone ever take a Franky copy, plug it into a Bandmaster and dime it....and compare that tone to a 1968 Plexi?? That might be the secret right there (splitting the difference between a dimed Marshall=deafness, and an overdriven Bandmaster at something "workable" for a guitar player.,

I remember even then, "I need a Bandmaster!" since Ed's ears thought that was his best tone he had achieved........

[wjamflan]

Not being a techie, I've been following this thread with great interest from the sidelines. Is there someone who could sum up all the findings in layman's terms?

Was it simply a 12 series Plexi with a bass mod and later, a JMP OT? Any help would be greatly appreciated, b/c all of the cap values are like Greek to me. Thanks.

Bill

[rgorke]

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

1) What do the bypass caps have to be rated in terms of voltage? Is 50v enough or do they have to be 400v?
2)I think John Suhr also mentioned that putting a 560pf in the mixer (or was it the tone stack? or both) makes a difference as well.
3)This post in and of itself should be a sticky.

[vh junkie]

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

1) What do the bypass caps have to be rated in terms of voltage? Is 50v enough or do they have to be 400v?
2)I think John Suhr also mentioned that putting a 560pf in the mixer (or was it the tone stack? or both) makes a difference as well.
3)This post in and of itself should be a sticky.

50v is plenty(25v or 35 would work too) for the added (220uf to 470uf) cathode bypass cap, although you will see that the Sozo mustard .68ufs used here are rated at 160v.

The other coupling caps (Sozos, mustards,etal s/b 400v)

The little 250pf to 560pf that you see in tone stack and bypassing mixer resistors are usually 500v.

[Strat78]

Not being a techie, I've been following this thread with great interest from the sidelines. Is there someone who could sum up all the findings in layman's terms?

Was it simply a 12 series Plexi with a bass mod and later, a JMP OT? Any help would be greatly appreciated, b/c all of the cap values are like Greek to me. Thanks.

Bill

I think it is pretty much summed up in George's 68 kit. Here is a clip, guitar, Echoplex and 68 Metro 100w; volume on 8:
http://soundclick.com/share?songid=9451688" onclick="window.open(this.href);return false;
I'm not saying this is the exact tone (low E string snarl is not there yet), but allot of the earmarks are there for an amp that is not even broken in yet.

[vh junkie]

I love it! Strat78s essential licks version of ATBL!

Is this recording with some of the mods discussed here?

[Strat78]

I love it! Strat78s essential licks version of ATBL!

Is this recording with some of the mods discussed here?

No mods yet.

[spaceace76]

Awesome clip Strat78! When the amp breaks in it should be even closer, but right now it definitely has the core tone. The only differences I hear are perhaps the pickup (we'll never know for sure what Ed used on the album, other than Super 70's), the new mod, and all the fancy studio processing stuff, compression, mic preamps, eq, etc. Well done!