Amp makes fizzy noise when passing signal

[aleclee]

I just got my Soldano Decatone and it makes a fizzy noise when passing signal. I hope you guys can hold off on the fizzy Soldano jokes long enough to hear me out.

Even on the clean channel, the amp makes a hissing/fizzing sound, but only when it's passing signal. When idling (not playing or guitar volume turned down) it's dead quiet. I've tried swapping out preamp tubes and pulling duets but with no joy.

I'd just as soon not have to ship a brand new amp back to the Manufacturer for service.

Help (and thanks)!!!

[prsflame]

I had a very similar problem in My Soldano reverb-O-Sonic. After swapping tubes, etc,and taking it to a tech, the problem ended up being related to a bad input jack on the amp.I never thought the input jack could cause this kind of trouble.Once this was replaced, all was well.

I'm no amp expert, so hopefully others with more knowledge will chime in.

[aleclee]

Thanks for the tip but no joy. I tried using the other speaker jack and running a cable across the FX loop but no joy. I also pulled the chassis but didn't notice anything obviously wrong.

[John Phillips]

It could be a tube, but more likely something tricky to find - probably a cold solder joint. These can occasionally develop semi-conducting properties and behave like diodes, either causing weird distortion and noises or even picking up radio.

Does it do it if you plug directly into the FX return? (you may have to preamp the signal with a pedal or something) If so, you know the problem is in the power amp. If not, it's in the preamp.

[aleclee]

Thanks, John. After inspecting the amp, I'm suspecting a cold solder joint as well. Looks like this amp is going back to the factory for a looking-at.

[Adam]

The phrase "passing signal" struck me as funny!

Thanks
Adam

[ross]

I make a fizzy noise when I'm passing gas.

[burningyen]

I make a fizzy noise when passing judgment.