Princeton reverb- reverb pot is a gain control

[fdesalvo]

Hello! Have a 72 Princeton reverb on the bench that’s distorting heavily with the reverb tank plugged in and reverb level above 4. Level acts like a gain pot. Sounds like blocking distortion.

Amp arrived with a decent cap job completed. Customer states this wasn’t an issue prior to previous tech’s bumbling. Thought maybe the screen filter cap node was going south in the ce cap can, but it’s fine. Voltages look great with no leaking coupling caps or conductivity on the board. Has anyone seen this before?

[g1]

Does amp volume seem normal with tank disconnected? If not, maybe the dry signal is not all getting through.

[fdesalvo]

Hey brother just got it sorted out. Parasitic oscillations at recovery tube and the rest was blocking distortion which I was able to clean up. She’s back to beautiful! Ty for responding.

[g1]

How did you deal with the blocking distortion?

[fdesalvo]

How did you deal with the blocking distortion?

I trimmed low end from the first 2 stages and added a 1m grid stopper on the pi input. That made a very noticeable difference. Once I removed excess wire length and rerouted the wires on the recovery socket, the remaining fuzz was eliminated. Now the overdrive is smooth and much tighter.