Picked up a 1959hw a few months back and everything was fine. But now it seems cranked when the volume is on one. This happens when plugged into either of the two inputs with the matching volume, and when jumped. I know this amp has a lot of power, but 1 is just blasting and when I connect my hotplate attenuator, it is lighting up the room when the amp is on one. (lights roughly indicate how much power is coming out of amp). I will probably take it to a tech (Im lucky to have a marshall certified service center not far from my house), but I am capable of doing doing basic trouble shooting on a tube amp. Any suggestions as to what to look at that would cause this?