Amp makes high picth sound but not feedback

[Jam]

Stage 160

Which ones are feedback caps? but I didnt see anything broken. Ok when I have the guitar turned down all the way and turn the reverb all the way up the noise starts and takes off on the clean and dirty channel.

[tubeswell]

Could be your reverb pan feeding back. Stick the pan inside a plastic bubble wrap and see if that quells the noise.

[Jam]

Stage 160

I covered the pan with bubble wrap and it helped alot and when I took it off it come back loud . So what does that mean? How do I fix it ? Thanks

[tubeswell]

Well I'd say that's reverb pan feeding back for sure. I'd start by keeping the steel side of the pan face down, and put some stiff cardboard over the open side of the pan to protect the strings, and then wrap the whola caboodle in some padding (i.e.; put the bubble wrap back on), and see what that does.

If you are still getting howling after that, then I'd look at your pre-amp tubes to see if any were microphonic

[52 Bill]

You can buy or build a vinyl bag to put the reverb tank in, just like a lot of other amps use.

This is a solid state amp no tubes.

[Jam]

stage 160

So why do I need to do all this stuff with the reverb pan? It worked fine for many years with out all that and I have about five of these amps and they work fine with the pan not coverd

[tubeswell]

This is a solid state amp no tubes.

Ooops didn't read the start properly

Well since the OP got the problem when they soldered in a new part, it is worth looking at that soldering job. Could be bad soldering/cold joint, dirty solder etc - those things can cause weird oscillations

[52 Bill]

Try swapping the reverb tank with one from another matching amp. That way you will know if it's the tank or the amp that's different from the others.