I’ve been searching the web for replacement tubes for my vintage Ampeg Jet J12-T. I was suprised to find that the recommended tubes on the web did not match what was printed on the inside of my Ampeg amp. Some folks on the web were saying that the amp only had 4 tubes (it really has 5) and they were saying that one would need (2) 12AX7 and (2) 7591 tubes.
So for anyone out there wondering, the documentation inside of the amp says this:
Tubes (from left to right):
6BK11 or 6C10
6C10
7591
7591
5Y3