How do these heads stack up?? (no pun intended) Trying to spend some of my buddies money on a new tube amp. (new for him, graduating from an old crate) He's a broke married guy like me so looking on the cheap. Got a line on an old model Carvin X100b for $399 and a Sovtek mig 50. Never played either. I think I heard where the Sovteks were kinda noisy. (?) Used to hear pretty good things about the carvin.. Any input??