so on saturday i finally got a new amp. its last years model ($50 off. yah!) and the master volume doesn't work. i can still change from lead to clean and can adjust the volume separtley. am i just missing something or is it broken. i wanna find out soon so i can get them to fix it.. thanks
if you just got it saturday, take it back and get them to fix it.
They should do it if you just bought it..

If they wont fix it (for whatever strange reason..), then open it up, see what value the pot is, buy a new one, and replace the old one with it.