Hi, I have a Marshall Valvestate S80 for my amp. When I turned up for practice today with it, the gain channel would not work, only the clean. Anyone got any ideas on what might be wrong with it? It is an old amp, but it has been working fine up until today. Thanks in advance.
It sounds like the channel switch has failed. It could be something as simple as a broken solder joint, or it could be more complicated. Have a qualified repair tech take a look at it.