I've been chopsticking around in my new blackface DR build while my friend finishes up the cabinet and I've noticed that poking at the filament wire run from the reverb recovery tube to the PI (no vibrato in the amp) can shut off the second channel. The first channel still works when this happens. Also, I seem to recall on instance where poking at the ground/cathode wire next to the filament winding (pin of the reverb recovery also shut it down. This is always done with the reverb tank disconnected and the reverb knob turned all the way down. It's happened with 2 different tubes in the reverb recovery stage (new EH 12ax7 and NOS Jan 5751).
Could some sensitivity between the filaments and the cathode be the root cause?
From what I can tell, there is no direct contact happening but because the cathodes of the reverb recovery tube are connected with a short jumper wire that runs straight above the socket from one cathode to the other, I can't really spread the pins out and there is a decent amount of solder on the adjacent filament/cathode pins, so there could be some contact made depending. I think I'm going to redo that socket so as to create better separation between the filament runs and ground.
I recently had insulation on some crappy wire melt while soldering to the sockets and it let the two filament conductors short where they were twisted together. Looked absolutely perfect until I disconnected the tranny, found the short and untwisted the wires.
It's not unheard of to have a coupling cap with a intermitant internal connection on one of its leads!
When you move / chop stick around that tube are you also moving around a lead of a cap?
Moved can also reveal tube socket grippers that can hold on to the tube pin(s).
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of the reverb recovery also shut it down. This is always done with the reverb tank disconnected and the reverb knob turned all the way down. It's happened with 2 different tubes in the reverb recovery stage (new EH 12ax7 and NOS Jan 5751).
