Microphonic tubes?

[Polera]

Everytime i stop playing on my amp, i hear a little 'whine' or scream come out of my amp when i mute. Is this microphonic tubes? How do i fix it? Thanks.

[Lordathestrings]

All tubes are microphonic to some extent. Its a matter of finding tubes that minimise it. Use a chop-stick, or a full-length, unsharpened pencil to gently tap on the tubes with nothing plugged in to the input. You will find that all of the tubes will ring or rattle a little bit, but none of them should make a lot of noise. Microphonic tubes usually show up by causing 'ghost notes' or uncontrollable feedback.

You didn't say what your setup is like, but if you're using external effects with a lot of gain, that may be where the noise is coming from. A noise gate may be in order.