Hi, recently i just broken the knob of the master volume of my fender super twin 75. How i can change the knob? The little bar is a little broken and it possible to change the volume but i dont think if i just buy a new button it will work. Help me please, because a do a show in 3 days . Thanks a lot!

Sorry for my bad english.
Um, what you could do (but i wouldn't reccomend it doing yourself, unless you feel confident with soldering) is find out what pot it was and find a replacement for it. Replace the pot and then put the knob back on.

There'll be alot more impractical (and risky solutions aswell) such as gluing the knob to it somehow. etc etc.

But perhaps you'll just live through the gig, and then see what you can do? I mean, noone in the audience should really care about a knob missing. Plus i have a fender strat with one tone knob completly bashed off. I can change it, cause one of the two rods still remain, but i can't be arsed to change the pot. I think that this gives my guitar some personality!
Oh ok i see i think i will call a amp tech for this. Thanks.