Static mystery

[royewest]

My S.E.X. amp (penultimate model with various nickle-core, C4S, pot, and other upgrades) suddenly developed static on vibration in the right channel.

I flipped the plate, plugged everything back in, tossed the kitchen for some wooden chop sticks, and asked my kid to dial 911 if he smelled flesh burning. Power on; in I went.

Poking at different components, the static was pretty bad, but always on the right channel. Sometimes I thought it was the Alps pot and the amb.org board/connectors I used with it (some are friction not solder connections); sometimes other components. But I just couldn't seem to isolate the problem with discrete wiggling(TM). Suddenly it occurred to me -- what if it's the tube? Tapping on the socket was one particularly good way to provoke the problem

So I flipped everything over, swapped the tubes and -- the problem is gone.

So here's the question for folks with experience with this sort of thing: is this a common occurrence: the tube just needs reseating or handling to settle back down? Is this a symptom of a failing tube. Any other ideas besides shaming me for the sorry soldering job I did on this early DIY project?

Thanks,

__Roy

[Paul Birkeland]

This could just be a case of a dirty tube socket.  A little bit of contact cleaner sprayed into the tube socket pin receptacles will give you some peace of mind.

-PB

[royewest]

Thanks, PB -- this occurred to me, too. I have the can of cleaner -- will take the beast outside and spray it tomorrow.

__Roy

[Paul Joppa]

Another possibility is "stuff" inside the tube. There is always some stuff - bits of mica, etc. - rattling around; it's usually benign but if it bridges slightly between electrodes it can make noises. Some recommend tapping the tube lightly on the table before inserting it, to settle things on the bottom.