Quote Originally Posted by tunghaichuan
With carbon comps, it is usually hiss, not hum so it sounds like you lucked out.
I don't know, maybe I did. With no input and the amp turned all the way up on the Champ clone, there's a very small amount of hiss. That's exactly what I hear out of my Peavey Classic 30 with no input on the clean channel turned up about halfway - and there are no carbon composition resistors in the PC30.

Actually the loudest thing I hear in the situation described is a tube. Probably the power tube. Cooking away.