Polytone Studio 212 Power amp repair - Sourcing NSDU57 NSDU07

[prulup]

Where did you get your LM391?
I had always suspected the ones I got were counterfeits, so I gave up on the repair

eBay, from China I am afraid.

[pontiacpete]

Good luck! I hope it works for you, then I'll buy one and fix the polytone under my bench.

[52 Bill]

Start a new thread for your amp and your problems. This one is long and already covers multiple issues.

What power transistors are you using?

[prulup]

I thought it would be better to post it in this thread as there are people who had similar problems with this amp. I am using the same pwr transistors, MJ4502 and MJ802.

[Enzo]

We understand your thought, it isn't like an offense or something. But it all works better when new threads are made. Trust me, you get better response.

[prulup]

ok:-)