First off, i would like to ask the question as to where the "HT Fuse" is located in a Peavey XXX head, or in any tube head in general, my amp turns on(lights and all), but no sound comes out. Its not anything obvious, i plugged my friend's head into my loop and cab and it worked fine.

Anyhow, i am trying to locatte the HT fuse, for some people seem to believe this could be my problem.

Also, if i am to replace my tubes (4 6L6GC's and 4 12AX7's) with the exact same type of tubes as were in it before, does my amp need to be re-biased?