A definitive, 12301 spec EVH layout, with detailed diagrams?

[Jeremy1283]

Im in. Let me do some testing with jnew and then i will share my pics!

[Blix]

Subscribed

[Jeremy1283]

Here's mine:



And here is the Dave Friedman spec from the 'Debate on Eddie's Plexi' thread (page 42), which I am sure you are familiar with:

Look unless all you guys are trying this on a 12 series amp you have no idea what it sounds like. Also none of you have a power transformer that is doing exactly what his does either. It sags about 70+ volts with normal wall voltage dimmed and 50 some volts with a variac on it. Also unless you are listening with original 6ca7s everything gets thrown out the window. The real key to get the right sound also is the treble cap. His amp has been restored with all mustards and a 560pf lemco treble cap and a 500pf little red cap out of a 69 era amp for the mixer bypass cap. Also the amp has been rewired with all original period correct wire out of another plexi. Now I have said this before the amp is biased to like 85ma with normal wall voltage and then dropped with a variac to 90 volts. This will bring the bias down to around 50ma. Now the way the feedback is set up and filtering works well with this setup. I was told the amp now sounds like it use to back in the day.

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

I tried most of the variations from stock on this list, various caps on V2, 100k NFB on 4 ohm tap, higher P.I. filtering. There are those on the forum here that got alot closer than I did to VH with some or all of these variations. I prefer stock specs, but I still run the amp with a variac at 100V, just over 400V B+.

your amp looks great! nice work