Tube Amp Archive

Update!
Thanks to all for the help .005 C45 was the culprit. The little sucker across V9 was leaking! Replaced it with a .0047. Working as expected now. Still going to recap though.

Thanks again!

The first stage is a Sprague 20 @ 600V. Yea I was thinking about redoing it anyway while it is apart. Is there a way to test this Echo OT (reverb transformer)? Temporarily I put in a 30 @ 500V (had it on hand) to see if fuses still went and it made no diff yet I disconnect the OT for the reverb and ...

1K resistor did not help but I did disconnect the Echo transformer and no fuses are blown. Does this mean that it is bad?

I will try that tomorrow. Thanks for your help thus far! Yes this is a great amp and SHOULD be restored properly.

Would you recap it if not shorts seem to be present down stream of the standby switch?
I love this old goat! Finally get a chance to get it out and here we go. Gotta love it though.

The power tube in question is the one for the V9 for the echo circuit the 7591 not the 7027. The can is new or 06 new but replaced with a 40/40/20/20 instead of the 40/40/40/40 that should have been there. C48 was also replaced but again a lower value. Still @600V but a 20 instead of a 30. Looks lik...

No goo. Only .022 coupling caps remain. But the caps were replaced in 06. Could the short be inside the cap can? Could a coupling cap cause this problem. Could the fact that some of the caps were replaced with 50% less caused them to go bad faster?
Thanks

Thanks for taking a look. Yea 5 is cathode whoops. I have attached a schematic

The fuse pops when all but the rectifier tube is out. Even the 7591. Fine with no tubes or with the rec in standby but on with the rec and no other tubes it will pop.

I am having some trouble debugging an old ampeg B12xy that used to be a fav. I have had the amp well over 10 years. I have pretty decent knowledge of tube amps but am no pro. I have built a bunch. Modded a few and debugged several but this one has me scratching my head. In 2006 (before I had any ski...