My brother just scored an old Fender showman guitar head, what little info I could find about it says that it's from '68-'70. It's an old silverface. This is the great part though.... $10!!!

I was just wondering, if anyone knows anything about these that could help us out. It doesn't say anything on it about ohms or anything. Plus, it works, but it makes some kind of harsh buzzing noises, and hums a lot. (We hooked it up through my 2x10 8 ohm bass cab briefly) Thanks for any help you guys can give, I know this isn't a guitar forum, but I've come to trust talkbass on anything music.