After having my JCM 2000TSL die (see the post I have on re-tube advice), I picked up another one which I was told should have a little bit of life left in the tubes.

The first week was fine, but it started making a funny noise, my drummer described it as "theres a baby in the cab" it's a high pitched, distorted squeal that isn't feedback (it still feedsback normally when I'm too close to my amp), it's present on all 3 channels at any volume. On top of that it's not noticable when I play, only when I'm not. I take care of it, but it gets the usual beating when moving it from car to room to venue etc, but i figured it should be made to handle general stuff like that.

Anyone had anything similar?

Perhaps pre amp valves?

any help is appreciated.

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squealing on all channels sounds like a microphonic tube in the preamp.

either that or a really bad cable, or grounding problem in the guitar or pedal chain.

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I had a feeling it would be microphonic pre amp valves. I'm getting the amp re-tubed (this time with some KT77's instead of 88's and some 12ax7's) in both the pre and power amp sections, i'm also having it serviced, so I should'nt have any dramas.

My guitars were fine through my other amp (before it blew up)

Cheers.

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