I have had power tube problems ever since I bought this amp. I have changed the tubes twice now and evertime I do about a month later I have to turn the master up to 11:00 just to get to band volume levels and the clean chanel is at an unusable volume (to quite) Has anyone else had these issues. I usually gig with the master at no louder than 9:00 and always keep it at 90 watts and that is pushing it. Any suggestions. I think its time to send it back to Mesa . I used my stiletto at my last show and that thing is incredibly loud and its only 50 watts.