#1
So a friend who rents out backline equipment has a weird issue with an amp:

"One of my Fender Twins is volume swelling on the vibrato channel. I'm having trouble finding info on it. I'm guessing it's that goddamned light, but maybe an input tube? Ever heard of this?"

Anyone have anything I can tell him before I just make him take it to the amp experts in town?
#2
This comes with virtually no knowledge, but I would try swapping around preamp tubes.
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#3
Hmm...never heard of that before. Usually the problem with the Vibrato is that it just doesn't work anymore.

#4
When in doubt, swap out 12AX7s.

Probably just V2 or V5 going.

Are you sure it's only on the Vibrato channel?


If anything is wrong with a tube amp, swap preamp tubes, then ask questions. They're cheap enough, and usually the culprit of problems.
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Last edited by Offworld92 at Nov 18, 2013,
#5
What he said ^.
V2 is the input tube for the vibrato channel and V5 is the actual vibrator.
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