odd mush with clean channel

[Guitarist]

I got a plexi style preamp/amp and I can't figure out why it goes to absolute garbage at around 2 or 3. Voltages read fine though the plate volts are higher than normal. Ever had something weird like this?

If you check for a leaky blocking cap does it have to be disconnected?
There's no sig V on grids except fot PI which is around 18 V.
I've subbed in tubes as well.

Thanks a mill, Guitarist

[R ski]

Mushy

Few questions on the amp

Is it home built?

If so........then are there large values of cathode by pass capacitors on the first two preamp stages...........they result in gain........but the set back is a mushy overdrive sound

The coupling capacitor, best to check with ohm meter......once the B+ is drained...with meg ohms........and free of your fingers contacting the probes..........should be no reading........leakage will offset the next stage

[Guitarist]

The amp is a Pignose G40 that I added a relay to to by bypass the second stage. Hence the olde school Marshal mode. The cathode caps are 1uF.

So I'll check those caps in circuit with the power off. I have a custom 1/4" cable that I'll use going through the stages to try and isolate it but I believe it's in the preamp.

Thanks.

[Guitarist]

Still working on it. I've been listening to the guitar sound at varous stages n the circuit. It fine up until the bottom grid of the PI which is noticeably more distorted and quiter than the top (schematic wise). Is that normal?
I replaced the 1Meg resistor and the cap and added a seperate/redundant ground wire.

Maybe I'll pull out eh feedback circuit and presence altogether and go OrangeMkII/Matchless Clubman. I don't need wicked volume but great tone generation.

Also of importance no doubt, I isolated the speaker ground from the chassis as I was getting loop noise when slaving it out (5 Ohm load on 4 Ohm output jack). Now the speaker's ground is at the following end which is grounded to the back panel metal.

[Guitarist]

Just to state the progress: the PI is balanced now (82K and (97K), It's very dark and V1a sounds like a Big Muff, more wool than a Dall sheep on Rogain. Inserting the axe after that is better but hard to tell.

Perhaps the filter caps are toast (Pignose right) but they're all mounted on a PC board and I don't know the method for testing these things. Does one remove it connecting + again and insert the meter to test for current?
Thanks.