Blair wrote:Has anyone used a JJ multicap in place of the metal can? I know these run hot! Will the JJ can survive?
I can't bring myself to cut this fellow up even though it had a power transformer that broke down and the rectifier and HV taps were fused. I had a spare PA-060 and it had a bell dent, so I robbed the bell off the old one and replaced it. The original board looks pretty decent also. Is there anything I really need to watch for on these amps?
The JJ caps are rated at 500V. The turn on surge could over-volt them. You could series two 385V or two 500V JJ caps, if there is enough space. F&T makes smaller 550V axial electro-caps.
I would not use the old driver board. The caps probably need to be replaced. Coupling caps can catch fire. The bias supply (electro-caps and old selenium rectifier) needs to be rebuilt. Bite the bullet. Strip it, get a new board, re-cap it, get a new bias diode and new sockets. You'll be glad you did.