EVH plexi observation....

For all things to build the brown sound

Moderators: VelvetGeorge, RACKSYSTEMS

User avatar
plexified
Senior Member
Posts: 856
Joined: Sun Dec 25, 2005 12:49 pm
Just the numbers in order: 13492
Location: amidst the wreckage of a hot Plexi

EVH plexi observation....

Post by plexified » Tue Mar 21, 2017 4:38 pm

Sometimes things are in plain sight and it goes right over your head.

This may be the case regarding the VII preamp board pictures in Eds main Marshall.

Within stock specs we all know that Eds tone is definitely found. In pictures and descriptions posted by some folks that worked on the amp it was noted that VII had a large electrolytic or larger electrolytic placed in this position bypass. Stock was up to a 330uf with an 820 ohm . So the premise of the debate was regarding this part compliment. Ok.. so

My observation revolves around the pics did show a quite large electrolytic , while this cap is lower voltage and usually not that large.

So this is where its out in the open and over our heads. The pre amp electrolytic supplying the power section is located here in a stock 68 board. Its usually a dual can (16uf x 2 , 32uf x 2 , 50uf x 2 / stock values here) Again one can , two separate supplies.

Here is what is curious , occasionally values are not available in this configuration or you want different values in each stage , whatever. But this leads to the use of TWO separate electrolytics in this area. This will look similar to what was happening in Eds amp. Two large electrolytics.

And , a common trick is to bypass these electrolytic caps with small value non electrolytic caps to bypass certain frequencies and tweak that stage.

So my point is that it is VERY plausible that both situations could have occurred here.

1) a VII cathode electrolytic that is very large as was pictured

2) a separated pre amp power supply electrolytic (16uf radial) bypassed with a .68uf - .022uf

Both situations could have occured and looked exactly the same from a picture , because the size often obscures the smaller part and the direction its going or relation to.

That's visually , tone wise they both are Very effective tone shaping situations here that either or could have provided similar results.

Just when you thought it was over :listen: Plexified

jnew
Senior Member
Posts: 1577
Joined: Mon Jan 07, 2013 9:34 am
Just the numbers in order: 13492
Location: Front Row Seat From the Outer Continental Shelf

Re: EVH plexi observation....

Post by jnew » Wed Mar 22, 2017 10:05 am

I think I follow you Brutha plex but if those those preamp 16uF points were bypassed, I would think that and equal 450V size cap would be needed for integrity. And if a smaller was used and hidden, then that would mean a mod. Not stock. So it's possible and just kept very secret?
________________________________
I SEE THINGS BETTER, WHEN I LISTEN


http://www.soundclick.com/bands/default ... ID=1214336" onclick="window.open(this.href);return false;

User avatar
plexified
Senior Member
Posts: 856
Joined: Sun Dec 25, 2005 12:49 pm
Just the numbers in order: 13492
Location: amidst the wreckage of a hot Plexi

Re: EVH plexi observation....

Post by plexified » Mon Mar 27, 2017 1:58 pm

That is a good observation,
My premise is based on questioning the photo and going by testimony from those credible that observed the amp. Its based on the tight lip speak regarding keeping the comments low key.
I am pointing out that its possible to have the two caps that are ordinarily either a single can with say a 16x16 filter or two cans separate. If its separate cans , two 16uf , some mount one on top of the board and one underneath OR two on top of the board. And if you relate two on top of the board they would have one in the standard position and the one in question towards the preamp part of the board. Here I point out that it could appear to be in the VII position and sit in the same area obscuring the area of the presented picture where VII shows the large cap. In this premise , its possible to have it both ways visually. And if both cases it shows tone tailering. And you are correct , it its a bypassed filter stage with a small capacitor like a .022 underneath, unseen in the pic , its a mod although a common tube circuit application.

In both cases you get some gain , however in two different frequencies. One accents the high end and one the low end gain.

If you were to go by the picture also , you see Cornel Dublier chocolate drop caps on the board and you see the values are consistent with .022 in the preamp and in the phase inverter input. The phase inverter input is perhaps a bigger deal , because it globally filters low end from the entire amp. And VHI is not floating a lot of bass in the recording, in fact its peaky in the 4k area. ANd its also letting accentuated high end through according to the frequency on tape.

jnew
Senior Member
Posts: 1577
Joined: Mon Jan 07, 2013 9:34 am
Just the numbers in order: 13492
Location: Front Row Seat From the Outer Continental Shelf

Re: EVH plexi observation....

Post by jnew » Mon Mar 27, 2017 6:10 pm

So then we must not be talking about a 400+ V electrolytic cap. That would probably be too big to hide. You must be talking about signal type cap. Like a mustard .022/400V or something in that size range.
Seems weird to be bypassing a filter cap with a cap but then again, a variac between the head and cab was weird once upon a time. :lol:
________________________________
I SEE THINGS BETTER, WHEN I LISTEN


http://www.soundclick.com/bands/default ... ID=1214336" onclick="window.open(this.href);return false;

User avatar
plexified
Senior Member
Posts: 856
Joined: Sun Dec 25, 2005 12:49 pm
Just the numbers in order: 13492
Location: amidst the wreckage of a hot Plexi

Re: EVH plexi observation....

Post by plexified » Mon Mar 27, 2017 6:58 pm

actually I am talking about a 450volt cap . And I am also talking about a 600volt signal cap .

A electrolytic filter of say 16uf or 32 uf can be the same size as pictured. In the blurry markings its two numerals followed by the voltage rating which is too blurry to be read.

Either way it sits above its either smaller bypass say polypropelyne cap or resistor depending on how its used.

Understand taken as previously discussed here, the electrolytic was on top of say an 820ohm resistor and a .022 cap.

My comment is that it may also be the preamp filter with a .022 plastic signal cap bypass under it also.

That's why I reference it as 'out in the open' , buy not observed. And the comments do not clear it up.

They are both plauseable mods either way. Its clear that the cap is a mod. If it were a standard Super Bass bypass cap it would be the same size as the one used on the split on the beginning of the board. And its not. Its in addition to. Placed on top , obscuring its purpose. So it goes both ways in definition or speculation. Both valid tweaks , both valid results.

User avatar
JimiJames
Senior Member
Posts: 3550
Joined: Fri Dec 23, 2005 6:32 pm
Just the numbers in order: 13492
Location: Chicago
Contact:

Re: EVH plexi observation....

Post by JimiJames » Tue Mar 28, 2017 12:24 am

plexified wrote:...That is a good observation,
My premise is based on questioning the photo and going by testimony from those credible that observed the amp. Its based on the tight lip speak regarding keeping the comments low key.
I am pointing out that its possible to have the two caps that are ordinarily either a single can with say a 16x16 filter or two cans separate. If its separate cans , two 16uf , some mount one on top of the board and one underneath...
Now ^that^ is good observation !
RIP Mark Abrahamian-rockstah -classmate/roommate
RIP Ben Wise -StuntDouble- comrade-in-arms

__________________________________________
Build'sClip'sVid's

jnew
Senior Member
Posts: 1577
Joined: Mon Jan 07, 2013 9:34 am
Just the numbers in order: 13492
Location: Front Row Seat From the Outer Continental Shelf

Re: EVH plexi observation....

Post by jnew » Tue Mar 28, 2017 7:29 pm

Ok. I think I'm good and lost so I'll just ask straight out. Are we talking about running .022 signal caps in simple parallel with the two 16uF electrolytic pre-amp filter caps, regardless of whether or not it's a single dual can or two separate single cans? That's what I'm taking away from this. Each 16uF pre-amp filtering value has a .022 running in parallel. Sound right? :wink:
________________________________
I SEE THINGS BETTER, WHEN I LISTEN


http://www.soundclick.com/bands/default ... ID=1214336" onclick="window.open(this.href);return false;

User avatar
plexified
Senior Member
Posts: 856
Joined: Sun Dec 25, 2005 12:49 pm
Just the numbers in order: 13492
Location: amidst the wreckage of a hot Plexi

Re: EVH plexi observation....

Post by plexified » Wed Apr 05, 2017 7:08 pm

Yes , J, Yes , you are on to something so lets look a bit more closely to get ya on the same page.
So , the thing to take away is the theory here. If you bypass an electrolytic which is slow in its process and compromises high end flow , you just bypass a film capacitor to flow the spectrum that got stuck. Here you can tune the stage. Here , we are talking about stage one and tuning it with a bypass cap of low voltage , say 400v and its plastic and on polarized and it bypasses the stuck frequencies and gets them to move on and sounds amazing.
So we get back to the fucking world so. Fuck that world. The cap in VII is a .68 , 25 , 250 , 330 in usual Marshall nomenclature. Fu&% yeah man and take that concept and let it sit.

Because whats going on here is what you cannot seem to grasp . A stage one filter capacitor is usually either on top of the board , along side the other spec on the board or a can . THAT is not the end of the story. You have the possibility of the cap on the top board and one underneath the board. SO here we are with this thing you seem not able to digest.

Now It is a simple concept of VII having a framed spec , lets say 820 resistor , with a plastic .68 and a 330 uf electrolytic on the same position.

Ok , big separation here with concept. Next we have stage one electrolytic and stage electrolytic and they are either one can with a say 16 x 16 . got it ? or they are a modern 50 x 50 modern outside the chassis. We are talking inside the chassis here. So the big 16 could be on its point or it could be to towards the front stage and here is where we are talking about. So put a plastic .o22 on your first stage 16 uf logistically and you are now in my zone here.

User avatar
plexified
Senior Member
Posts: 856
Joined: Sun Dec 25, 2005 12:49 pm
Just the numbers in order: 13492
Location: amidst the wreckage of a hot Plexi

Re: EVH plexi observation....

Post by plexified » Wed Apr 05, 2017 7:23 pm

yeah man , that's the take away. Bypass plastic to forward the high end or frequency of choice. The electrolytics are slow , so its the basis of the concept.

That's my point here , first stage electrolytic and second stage electrolytic with physical and sonic results. Its both in the main stage and needs to be figured out. One may work for you and not the other , and visa versa. Its a valid observation and a bad ass one once you get it . It just gets down to small variances that stack up and ultimately select your own stack of tuning scenarious and get your own tone. This kid was bad ass and he just opened up the flood gates.

jnew
Senior Member
Posts: 1577
Joined: Mon Jan 07, 2013 9:34 am
Just the numbers in order: 13492
Location: Front Row Seat From the Outer Continental Shelf

Re: EVH plexi observation....

Post by jnew » Wed Apr 05, 2017 8:05 pm

Ok. Pretty sure I understand it at this point. Will just alligator clip them in the circuit and take it for a lap or two probably by the weekend. Will post back. Or post clip. One .022 per 16uF for starters. :thumbsup:
________________________________
I SEE THINGS BETTER, WHEN I LISTEN


http://www.soundclick.com/bands/default ... ID=1214336" onclick="window.open(this.href);return false;

jnew
Senior Member
Posts: 1577
Joined: Mon Jan 07, 2013 9:34 am
Just the numbers in order: 13492
Location: Front Row Seat From the Outer Continental Shelf

Re: EVH plexi observation....

Post by jnew » Wed Apr 05, 2017 8:09 pm

By the way, what pics of the circuit for VHII. I thought VH II pics were in the studio with the head on the floor and beer cans all over the place and DLR with his foot in a cast. Where can I see the circuit board clips?
________________________________
I SEE THINGS BETTER, WHEN I LISTEN


http://www.soundclick.com/bands/default ... ID=1214336" onclick="window.open(this.href);return false;

User avatar
plexified
Senior Member
Posts: 856
Joined: Sun Dec 25, 2005 12:49 pm
Just the numbers in order: 13492
Location: amidst the wreckage of a hot Plexi

Re: EVH plexi observation....

Post by plexified » Mon Apr 10, 2017 3:02 am

Im pissed the pic I am trying to link is going nowhere.....

The VHII staged recording Zloz photo just shows tube shields which effect tone and the output transformer that was changed as well as the choke. The choke is really a flavor and the OTX is a lower impedence and larger iron that grinds more in the odd order harmonics with more authority in terms of volume and lower impedence. Its the power transformer that sags that is still the tone shaper here.

If we fast forward we get guys under the hood that talk about a lot of variances. I broke it all down both from pictures and reports as best we could. We see a few thing happen here. After VHI we have Ed wanting to get more clarity or get away from the reverb wash. The Verb was a big discussion. It was the Sunset Sound treatment from the studio and the engineer whom was Don Landee. Templeman states he was a guitarist and Eds tone and playing lured him into signing him as he was a vice president of Warner Brothers. Mo was the Prez and it shows he had major pull to sell the deal , regardless of Gene Simmons demos and other attempts, he just used his ears to 'know' that this kid was undeniable. His late stage comments regarding a Seinheiser with removed Marshall grille cloth tells us that it was 'another' mic in the infamous Sunset Sound mix in addition to the Celestion and JBL tight microphone. That makes three tight microphone sources plus a re record with the Sunset Sound reverb chamber all analog that adds massive colorization. When the band comes in to play he also had all the room microphones as the whole gig was recorde live for well over two dozen live songs.
From here you get to VHII and WACF and then you get Celestion vintage 30 speakers , a 5150 studio, a Duncan wind that goes two ways in a 78 wind and a Custom Custom in which it started with a Duncan hot ceramic Duncan Custom ceramic mag design and a variance with an an Alnico II design. Its important to note here you had Chris M**rum in the mix. Chris introduced the dual variac as well as the Mod that Twisty made famous with his applications of the transformer resistance mods. Fair Warning was the VIntage 30 tight balls that made the album as well as Ed and Wild Turkey recording in the wee hours of the night and even re tracking. I worked at the Kramer factory and my friend and technically my supervisor Paul Deceasare was buying all the plexis and the liason with Ken Fischer from Trainwreck that was tweaking all the heads going to Ed. One of which Paul and Ken went through I still own now.
So the Schematics do not exist , the photos are pending , the one from Cameron is dissected in the past as I went through the period parts , and we get into the photos that have pink wire which appears to be Teflon and is quite hack. A quality tech as would be , Friedman , Cameron, Suhr, Fryette, Van Wheelden all would walk softly in that amp. Definitely map it , but walk away with minor measurements.
I can assure a lot can change in one year. I have a very prized amp I won't disclose that has recently changed by a crazy amount in the capacitor power stage that boggled my mind. All the values drifted so high I was amazed. All consistent. Even another amp no relation had specs just go way up. So time really makes a difference. If the Capacitance goes up its an introduction of energy that takes the power supply towards a low end focus and the power it takes to produce those frequencies is huge. Lets just be clear that a bigger lower frequency can be larger that the room. That's why you hear music in cars blocks away and that is a huge wave that takes massive energy and if you get down to single digit hertz as in earthquakes it shakes the tectonic plates. And Jnew that is your world my friend! So I know that gets your attention , and I also know you already know that, new readers can enjoy that factoid just tuning in.
So by Fair Warning we had a new animal here. A lot of amps in Eds stable and even Vintage 30's which is signature first notes after the slap pop intro to mean streats and the gut wrenching intro before we had tuning down for effect. Of course after Unchained dropped D tuna.
So on the schematic separate the incoming power supply voltages. Take the first stage and call it a 16uf , a 32 uf or a 50 uf and bypass that power supply rail with a .022 polypropelyne orange drop 600v capacitor and you feed stage one input with a high end bypass that adds sizzle.
My observation is based on the size of the cap in the picture and description of a 330 uf which is a stock lower voltage electrolytic. Lower voltage and smaller on the signal schematic, on the power rail its a larger voltage and size. 16 or 32 or 50 and much larger. Some on the board top as viewed looking down on the board out of the box looking down and some under the board. Radial meaning leads on each side of the 'tubeular shape' . Cans would have all leads on one side.

In this floated pic , you have crazy pink Teflon leads, a rewire mess throughout, from left to right.... A silver electrolytic probably a 250 fender era, a square yellow phillips mid to late 70,s .68uf then a CDE chocolate drop .022 a blue MICA .0022 then another mica brown 500pf and a large black XX unknown electrolytic almost as large as the light blue 32uf power filter. Next a brown mica say 250uf pair of .022 mustards and after the light blue as specified earlier a DCE chocolate drop .022 . So total non stock tuning or just tuning attempt, but NOT a natural progression as ALL these parts just do not FAIL . You also see nuts on the tube sockets , CERAMIC tube sockets at that, and a solder fuck fest.

That's your picture. notice ALL the WIRE WOUND RESISTORS, again total freak show might as well call this FRANKESTEIN TOO. Two different input jacks wrong color wire all over , solder burns and shit solder. NO PRO JOB HERE.

So back to the point . LOOK at the black electrolytic. We see only ONE power electrolytic ( light blue) on the right , second stage. Where is the first stage filter? Its the Black filter towards the left? Whats under it? The circuit has to work and again my theory applies here. Forget about the junk. A first stage power filter could be bypassed by a lower value poly cap to boost gain and high end.

User avatar
plexified
Senior Member
Posts: 856
Joined: Sun Dec 25, 2005 12:49 pm
Just the numbers in order: 13492
Location: amidst the wreckage of a hot Plexi

Re: EVH plexi observation....

Post by plexified » Mon Apr 10, 2017 3:24 am

after stupid struggle here is the pic mentioned above , nope , epic fail sorry , gonna mail it to Jnew see if he can post it . Sorry , I'm very pissed too.

jape88
Senior Member
Posts: 712
Joined: Mon Apr 14, 2008 6:55 am
Just the numbers in order: 7
Location: England

Re: EVH plexi observation....

Post by jape88 » Mon Apr 10, 2017 3:31 am

Do you mean H magnet 30's? the Vintage 30 didn't come out until '86? I've always stuck to Ed using 25's, green and black.

In the VH2 pics the jbl mix cab is missing from the shot and is (imo) in the reverb chamber (miked) and it's this that's the recorded tone not the loose mikes in the zloz pics.
Image
Last edited by jape88 on Mon Apr 10, 2017 3:51 am, edited 1 time in total.

User avatar
plexified
Senior Member
Posts: 856
Joined: Sun Dec 25, 2005 12:49 pm
Just the numbers in order: 13492
Location: amidst the wreckage of a hot Plexi

Re: EVH plexi observation....

Post by plexified » Mon Apr 10, 2017 3:45 am

Yeah its Vintage 30 H mag. Ken Fischer was in R&D with Celestion for the Blue Alnico engineering and along the way the VIntage 30 paper coil was what was in development. Ed was using these in the studio (5150) While it was being built and Ken was engineering all the prototypes with Celestion at the time. The Trainwreck Express was a circuit that was engineered from this timespan. I was their through all the engineering and all the mods and all the repair work Ken did , its a very overlooked thing. A Plexi with all 6v6s was one of his tongue in cheek mods to this . He played for years with at least ten ways to get the VHI tone with various approaches and nailed it each time. He was a great mind.

Post Reply