Hi, i've been having trouble with my bass amp - it emits a loud hum whenever i turn it on, even with the mute switch turned on. i left it in to be repaired, the guy in the shop reckons its "gone DC" and will repair some big money to get it fixed, i got more concerned with how much repairs were going to cost cos i'm practically broke and forgot to find out more about what he meant. anyone know enough about it to maybe hazard a guess? The only DC i know is Direct Current but i don't know anything beyond that electronics wise, i will in future though. guys in the army have to know their gun inside out, i should get to know my gear like wise in future!