What the hell is wrong with my amp?!

[Deleted member 21375]

I would suspect the tube socket connections first

 

[splatter]

Cracked solder joint. The amp heating up causes the problem to appear.

this, like I said earlier cold solder joint /cracked solder joint . Both will do the same thing .

 

[Blitzie]

Finally solved it today.

Bad power tube. Can't believe it. Easy fix.

Thanks for the input guys!

 

[Dave L]

Yeah, it´s almost always the tubes in one way or the other, and nice to hear it was an easy fix!

 

[shredhead7]

Like the others have said, it's most likely the preamp tubes. If it's doing it now without anything in the loop, it's most likely the 1st or 2nd tube, as those are always in use.