Whistling twin

Archie Cox · Post by **Archie Cox** » 8 Aug 2002 11:00 pm

Help guys! My Fender twin has a whistling sound which comes and goes. It sounds very much like a tea kettle whistling. The funny thing is, it's intermitant. I played using the amp last night and thought the whistling was gone, but tonight I practiced using the same amp and it's whistling again. What do you Fender guru's out there think it could be?

Chris DeBarge · Post by **Chris DeBarge** » 9 Aug 2002 4:24 am

Something you could check quickly:

Check the preamp tubes (the little ones) with the amp on. Just lightly tap them while it's whistling, and you may just hit the one making the noise and it will stop (or get worse). If you discover that, simply replace the tube. I hope this is your problem, because otherwise that thing is going to need bench service.

I've had the footswitch cause whistling on a Fender also, though I still haven't figured that one out.

Donny Hinson · Post by **Donny Hinson** » 9 Aug 2002 7:43 am

If it's not a microphonic tube causing the feedback, it could be a loose tube. This will also show up as a loud clicking off snapping noise when you tap the tube. To clean the pins and contacts, remove and re-insert each tube 4 or 5 times into it's socket. Lastly, it could be a bad bypass (small electrolyte) capacitor. This will cause all sorts of whistling and "motorboating" noises, which usually get quite loud when the volume or reverb is turned up. (This is a very common problem in older tube amps.)

Craig A Davidson · Post by **Craig A Davidson** » 10 Aug 2002 2:19 pm

It reminds me of my old 70's Twin. It would whistle once in awhile and I would put it on stand-by, pick it up an inch off the floor and drop it. When everything settled down it would quit for a couple months. Turns out it was an internal problem. I wouldn't have had it fixed, but it wouldn't whistle in the right key.

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1985 Emmons push-pull, Session 500, Nashville400, 65 re-issue Fender Twin, Fender Tele

Jay Ganz · Post by **Jay Ganz** » 11 Aug 2002 1:58 pm

Donny hit it right on the head (as usual).
Every old Fender I've worked on with that
problem had a cathode bypass capacitor that
had changed value causing that whistling
noise. Most of the time it affects the
reverb section, but whenever those caps
change (from age) it boosts the gain from
that particular preamp tube that it's
hooked to.

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Ken Fox · Post by **Ken Fox** » 11 Aug 2002 5:45 pm

Just fixed a Twin with that same sound in the reverb section! Boy, would it scream! I havew also had a high pitch whine from Chinese preamp tubes, especially in high gain Peavey tube amps!