Hey guys I've had this amp since it was new. Its the generation 1 model so before the Evo II and Evo III models. I've never had it tunes or serviced but recently I've noticed this high pitched hum coming through the speakers. Sometimes its because the high EQ is up so if I turn it down it goes away but if I'm using the DI on the amp into a mixer the hum is there. It never was before.. Any help would be appreciated. Its audible on Relax and The Storm on my sound cloud at the beginning of the latter and the middle to end of the former. Thanks for the help https://soundcloud.com/kishore-k-mukherjee/the-storm Is it a ground issue in my rig? Its just the amp. The pedals are in a 2 prong outlet and the looper is into the guitar amp as well so I'd expect the sounds to come from the guitars line too but its only bass.