I recently purchased a Fender Supersonic head. I know valve amps are noisier than solid state but the clean channel on the amp, especially the Bassman setting has lots of background hiss. Even with no guitar plugged in and the volume completely off, there is a hiss that is very loud. The lead channel is fine and I have checked cables, different speakers, different wall socket, etc. I didn't notice this at the store as I was in a big room with quite noisy surroundings. I took the amp back and they sent it to Fender who have replaced a suspect preamp valve and apparently tested the amp. Got it home and there is still lots of hiss. Anybody here experienced a noisy Supersonic amp? If not, what is an acceptable amount of background noise? Recording is going to be impossible with this thing! Cheers!