Debate on Eddie's Plexi

[Good Guest]

You know I think you may be right......if anything is making sense recently this circuit is. It's a 12 series transitional and that frequency curve is the icing on the cake for a vh1 spectrum analysis...and yes siree more bass would would be the vh2 tone..throw in the standard fx , this should be the circuit everyone plays with for a while....this could very well be the core tone.

The white knob at the back is starting to make sense as a possible

VariableBoost.jpg

fine tuning control for the bass also....seeing as it appeared around vh2 Kind of like this diagram but not identical to it.

[leadguy]

That circuit would have balls in the mids and upper mids but also be on the bright side.

Jose white knob switch for a on/off more bass or less treble mod and eventually the more bass mod gets put in permanently and the white knob switch removed.

It starts making sense.

[spaceace76]

holy crap. might even convert my 45 to split cathode just to try this out! sounds like it's really the ticket...

[Doug H]

You would think if it was STOCK there would be no problems with a simple pic of the guts.... The whole guitar world will be happy and everyone would go back to their STOCK plexi's and dig in till there fingers bled. Wondering how the hell he can do finger tapping on such a low gain amp.

Now if it wasn't STOCK and you wanted to mislead and sway people who are getting close to it ..you would do exactly what they are doing. You would have all these paid techs under your vh camp belt claiming a stock amp and providing no evidence. Kinda like government.

More bass in the treble channell only....hmmm rules out anything from the cathode follower on. Anyone care to speculate?

I'd guess a .022 instead of the typical .0022 in the treble ch.

or a differant value bright cap on the treble volume. Anyone else?

maybe a 330u on the cathode, didn't those amps use smaller values?

[Good Guest]

You would think if it was STOCK there would be no problems with a simple pic of the guts.... The whole guitar world will be happy and everyone would go back to their STOCK plexi's and dig in till there fingers bled. Wondering how the hell he can do finger tapping on such a low gain amp.

Now if it wasn't STOCK and you wanted to mislead and sway people who are getting close to it ..you would do exactly what they are doing. You would have all these paid techs under your vh camp belt claiming a stock amp and providing no evidence. Kinda like government.

More bass in the treble channell only....hmmm rules out anything from the cathode follower on. Anyone care to speculate?

I'd guess a .022 instead of the typical .0022 in the treble ch.

or a differant value bright cap on the treble volume. Anyone else?

maybe a 330u on the cathode, didn't those amps use smaller values?

The cathode on v1 or v2? There saying the amp has a .68uf on v2 as in the only clue were going to get ..so no fat cap across the 1K like we all were led to believe. So I guess yer saying on V1...would increase the gain and add lots of lows that's for sure....

[leadguy]

Here are the John Suhr bits I have found around the net about Ed's 12301 serial white knob Plexi.


The 2 non typical parts in this amp contribute to the gain in a very minor way. They were not major parts and the amp Already had the 680n at the cathode of the cathode follower."

i was told by bogner and john suhr that the amp was a stock 12series super lead,they both even told me what filter caps values the amp had in it.there stories match up with each other stock super lead with a .68uf/820ohm rather than the later circuit.


yes and also the .68u instead of a 330u on v2a


i was told by a member on this board a few years ago,and i wont say who,that he talked to john suhr about the EVH amp.john told him that it was bone stock but instead of the 2.7k on the v1b it had a 820ohm.he also said that the preamp filtering caps where replaced as well as the screens.


John Suhr has made the split cathode argument too IIRC.....he was a little vague in that thread (ampage?)

Ah..I see..yes there are some descrepancies there. Mark said that the serial # was 12301...which is what John said he had. My 12364 is split cathode. It sounds like Mark and John saw the 12301 amp and ****** and Plaap saw something else.
The amp I saw WAS 12301 I wrote it down in my book on the schematic, if that hole was ever anything it was a Master.
The first stage was split cathode Most definitely NO 250pf treble cap, no on the 100pf across the PI plates and nobody has mention the alternate Marshall parts that made a difference.
Ed must be laughing his ass off if he is reading all this stuff, You should hear him play thru his line 6 ! Also how many of you play with a thin pick?
Damm I wish I had a good digital camera back then !

Trust me, I never cared that much about THE AMP but I did write the number in my book as being 12301 next to all the specific voltages and parts marked in all red pen along with "Ed's amp" as Ed stood by me and dialed it in with the variac (light dimmer) and the amp open. All of the red paint on the solder joints was original and untouched except for one added part up until the Treble pot which could indicate a master at one point. Also if it wasn't "the amp" why would Matt his tech contact me out of the blue about 5~6 years ago to ask if I had done a schematic since I was the last one to see "the Amp" in it's original state? I'm not obsessed about this amp since it takes a specific type of player to play it, it is not a friendly amp and you need authority and chops to make it sound right but as Marshalls of that era go it is definitely my favorite. Piss ass loud amp too even when variac'd. Ed was sincere with me, where he was fuzzy was what he had plugged in to the amp between his guitar and the amp. I'm not shitting anyone, the amp was VERY close to stock but were not the typical values you find in a GT schematic book, it had more gain (stock alternate values) and a tweak for more bass which also increased the gain which was the only non stock value. Anymore than that I cant say without their blessing. It also "sounds" to me like VH1 had the variac turned up even though Ed said it was always down and used for volume issues, basically turned it into a 50W and would also clip faster in the output section due to lack of headroom. Bias could have been wacked as well since he didn't adjust it when he demoed it to me.


-----------------------------------------------------------

All of the above pretty well matches serial 12267 which is 34 serial numbers before Ed's

At least John Suhr doesn't BS.

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

[leadguy]

Now it's easy to see why when Ed was using the white knob Plexi 12301, it was mids/upper mids based and bright and why the small bass mod was done.
Combine this amp with a Echoplex EP3 and Ed's VH1 era tone starts to make sense.

My opinion is that Ed had the bass mod done after VH1 only because VH1 is so mids/upper mids based and bright, well to me anyway.

[Good Guest]

Now it's easy to see why when Ed was using the white knob Plexi 12301, it was mids/upper mids based and bright and why the small bass mod was done.
Combine this amp with a Echoplex EP3 and Ed's VH1 era tone starts to make sense.

My opinion is that Ed had the bass mod done after VH1 only because VH1 is so mids/upper mids based and bright, well to me anyway.

Well you got my vote ..it all fits like a glove..

[redozzman]

Just to give you an example... here are 2 clips of a Plexi that John Suhr worked on:

http://www.youtube.com/watch?v=3dmx5MNUtXk" onclick="window.open(this.href);return false;
http://www.youtube.com/watch?v=PLOvYA6ipMQ" onclick="window.open(this.href);return false;

And here is the one that Dave Friedman did for me:

http://www.netmusicians.org/files/94-DaveVariplex.mp3" onclick="window.open(this.href);return false;

Dave and John do the same thing to get the EVH tone. I would listen to those guys! Dave has done all kinds of work for me, and he's got me as close as I think I can get!

I must say your clip sounds GREAT, killer VH tone!!!!! I know your post is getting lost in this thread but that clip is sweet!

[vh junkie]

You know I think you may be right......if anything is making sense recently this circuit is. It's a 12 series transitional and that frequency curve is the icing on the cake for a vh1 spectrum analysis...and yes siree more bass would would be the vh2 tone..throw in the standard fx , this should be the circuit everyone plays with for a while....this could very well be the core tone.

The white knob at the back is starting to make sense as a possible

VariableBoost.jpg

fine tuning control for the bass also....seeing as it appeared around vh2 Kind of like this diagram but not identical to it.

Well, I guess we ought to give Merlin Blencowe credit if we are going to use his illustrations...

The chapter in question is freely available here:
http://www.freewebs.com/valvewizard1/Co ... _Stage.pdf
So you can read the overview of the circuit.

Now, let me see if I've got this straight:
a) 820/.86uf on first stage instead of 2.7k/.68uf
b) VH1 is recorded with this circuit
c) Something like this circuit is added before VH2 is recorded
d) Pics of the "amp" that show a 250uf or 330uf cathode cap on the cathode follower AND a ~1000pf coupling cap, areof a different amp entirely...

[motrock]

Just to give you an example... here are 2 clips of a Plexi that John Suhr worked on:

http://www.youtube.com/watch?v=3dmx5MNUtXk" onclick="window.open(this.href);return false;
http://www.youtube.com/watch?v=PLOvYA6ipMQ" onclick="window.open(this.href);return false;

And here is the one that Dave Friedman did for me:

http://www.netmusicians.org/files/94-DaveVariplex.mp3" onclick="window.open(this.href);return false;

Dave and John do the same thing to get the EVH tone. I would listen to those guys! Dave has done all kinds of work for me, and he's got me as close as I think I can get!

I must say your clip sounds GREAT, killer VH tone!!!!! I know your post is getting lost in this thread but that clip is sweet!

Thanks! Dave has my Variplex right now. Something blew in it. Not sure what it was. But, he's fixing it and I will be up and running again. I am going to try out a new pickup sometime. I am thinking the WCR Darkburst. My MotorCity is too low of output and a little too compressed for me! I need something right around 9K and it has to sound more open. Then I won't need an EQ or anything!

[Good Guest]

Can't wait to install this baby...say what the board attachment quota has been reached...for a 25k tiny jpeg.

Anyways a 2.2k potentiometer in series with the 820 ohm resistor ....named "Bass control for treble channel" would fit nicely with the .68uf

[vh junkie]

Can't wait to install this baby...say what the board attachment quota has been reached...for a 25k tiny jpeg.

Gotta delete some attachments in your profile!

Anyways a 2.2k potentiometer in series with the 820 ohm resistor ....named "Bass control for treble channel" would fit nicely with the .68uf

Please give me your thought on my a,b,c,d questions above!

[Good Guest]

Thanks VHjunky wasn't aware all these files were on me. Anyways here is the schematic I wanted to post:

TrebleChannelWithBassControl.jpg (25.24 KiB) Viewed 4924 times

Looking at that frequency graph leadguy posted pretty well spells vh1 so I'm totally convinced this circuit was used in VH1.....the pot will add bass and gain in the bass frequency..the higher you go it gets to the 2.7k the more " bass gain " you get...follows that VH2 does have more bass gain as leadguy pointed out and there is a thingamajig on the back of that plexi...stands to reason it COULD be something close to this...a switch or even something else that adds some more bass.


I slapped a 330uf in the v2 cathode like many others cause of the specs everyone SAID was vh1 and it does add gain but I long removed it and stuck back in the .68uf ..I actually had a switch to to switch it in an out...pretty well turned into a bass or mid switch. This ancient spec uses it and it would go good with more mids feeding it. It could go well with a vh2 tone tho ..damn I will have to put it back in thanks to this circuit.

I don't know about the 1000pf coupling cap but here is where more experimentation will be necessary...I wouldn't be surprised if it is as that would follow the formula for high gain circuit ala van halen especially in an uncascaded arrangement like this.

A 1000pf letting the highs thru in the preamp and that all important 560pf (slap that in the tone calculator and see how it affects the mids and highs) as opposed to a 470pf or 500pf , I think that's important also...this would be more than adequate for the most noticable high frequency gain...follow that thru with a phase converter with a .047 feeding it to add the lows back for tightness and then a poweramp with .1's to really add warmth and smooth things out and there is no doubt this spec would be a EVH contender...dare I say "The Brown Sound"..

Maybe the .022's in the power amp if using a .047 to feed the inverter..that needs experimentation also.

[StuntDouble]

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