Dumb Princeton Reverb question

brojangles

I've got a second hand PRRI on which the reverb has stopped working. First it got weaker, so you had to go to 10 to hear it. Now the reverb dial just adds hiss. Vibrato works fine.

I've checked that the reverb send and return cable is plugged in at both ends. Nothing obviously catastrophic going on that I can see in the reverb tank. Given that electricity might as well be little planets in the wires to me, and that I can no more solder or comprehend electronic components than I can fly to the moon, would it be more sensible to replace the relevant preamp valves and see how that goes, or just go straight to a tech? (ie how likely is it that the valves are responsible as opposed to something fiddlier?)

ICBM

Shake the amp with the reverb turned up. If you get reverb twang/crash you know it isn't the most common problem which is a broken output transducer.

If it got weaker rather than suddenly wasn't working, I would suspect the driver valve instead - V2, which is the 12AT7 second from the end of the amp. It won't be the return valve if the control adds hiss, that means it's still working.

brojangles

Whoa that was quick. Thanks very much.

brojangles

Much crashing and twanging... I'll replace the driver and see what happens. Cheers @ICBM.