the clean channel of my Mesa F-50 combo has this hissing noise that does not seem to go away. On the dirt channel it's gone. It does not seem to be influenced by the guitar at all since it's also going on when the guitar is not even plugged into the amp, and it's also present when the amp is at a low volume.
Any ideas what could be causing this and how to fix this? Could this be a bad pre-amp tube?
Wirelessly posted ()
Most likely culprit is V1, since the clean channel uses one half and the dirty channels the other half.