Peavey Classic 30: Help identifying mods

[clarisso11]

Good news, thank you for checking!
I might try some mods once everything is working as it should, but for now it’s good to know that I’m...

[clarisso11]

Thanks again for the advice, I won't alter the original circuit for now (especially knowing now that it likely hasn't been modded at all).

Can't...

[clarisso11]

I stand corrected! Just lifted one leg of one of those parts and measured it, and sure enough, no resistance! No capacitance either, but that would be because...

[clarisso11]

Some good points here. I decided to replace all of the large filter caps since two of them had high ESR, and the amp is now almost 30 years old.
I will...

[clarisso11]

Thanks everyone for the quick replies!



They are definitely resistors, look like the standard 1/4W type.
Here are photos of...

[clarisso11]

Hi everyone,

I recently bought a used Peavey Classic 30, since I heard good things about the amp.

When I turned it on it hummed...

[clarisso11]

I removed Q108 and Q107, and both tested fine. In the end, I went with the nuclear option: Bypassing the JFET switching all together, by converting to true...

[clarisso11]

Hey g1,
thanks for helping out! There seems to be similar drain to source resistance for both FETs, in-circuit, and power disconnected. Q108: 0.46 kOhm,...

[clarisso11]

Would the drop in resistance for Q107 mean that it turns on, but Q108 remains closed since the resistance doesn't change?


That's what's...

[clarisso11]

I just double-checked, and I get audio signal across both ends of Q108 and reaching one end of C114, but not the other side of C114.

I'm not...

[clarisso11]

Hi Enzo,

No broken traces from what I can tell. The added wires and resistors turned out to be adjustments from factory, you can just about see...

[clarisso11]

Hi everyone,

I'm working on repairing a 1981Ibanez CP9 compressor pedal, with a very strange problem: It works seemingly perfectly when turned...

[clarisso11]

Everything working now! In the end there were two faulty components in the voltage regulator circuit: The LM741 chip, and the BC309. I have re-calibrated...

[clarisso11]

Hi eschertron, thank you for all your help! Just saw your messages and figured I’d start with the BC309- I think we’ve found the culprit! Will...

[clarisso11]

Thank you for your reply! I have just unsoldered LM741, here are the pin voltages: 6.6V at pin 2, 19V at pin 7, 0V everywhere else.
Not sure where to...

[clarisso11]

Hi everyone,

I am currently working on repairing yet another Electro-Harmonix Electric Mistress, after having repaired one in the past with the...

[clarisso11]

D4 was the problem! I replaced it with a zener from an old Boss NF1 board, all workings again now.

Thanks again for the help, this forum never...

[clarisso11]

Thank you both for your help, I will check D4 as soon as I get a chance.



Enzo, since you have replaced these a lot, what part should...

[clarisso11]

Hi everyone,

I've been working on repairing a version 2 Boss DM2 analog delay, service manual attached. After sorting out a short at the potentiometers,...

[clarisso11]

Well said!...

[clarisso11]

I have just found the problem!

I was still confused by the fact that the LED had been on intermittently at some point, but I couldn't reproduce...