Peavey Triumph 60 Hum Problem

[Kidderman]

I just got burned on the purchase of a 1988 Triumph 60 combo which arrived with a hum which I believe is louder than it should be. The hum doesn't change in pitch or volume however the controls are set. I've checked out the obvious causes. Swapped the preamp and power tubes for tubes from another amp which I know are working fine. That doesn't make any difference. The filter capacitors have been tested by an electronics guy who tells me they're fine, so I'm pretty sure that's not the source of the problem. I've posted a video on You tube titled 'T60 hum demo' which gives a pretty good representation of what I'm talking about. Since buying the amp, I've been lucky enough to pick up a Vypyr tube 120 with Sanpera II for $170 which, apart from an issue with the headphone socket, is perfect. That's softened the blow a little with the T60, which I've now put up for sale on Ebay UK as is. However, because of the hum issue I may not get any interest and it would be a shame to have the amp sitting in my garage doing nothing. I know very little about how amps work or how to troubleshoot them. I'm aware that it may be due to numerous possibilities, most of which would be outside my technical capabilities. If there's a possible fix which anybody might be able to suggest which I may be able to try myself, I'd be grateful for any advice.

[Enzo]

We can probably have you isolate the problem, but any solution will require doing something inside the amp.

[Kidderman]

I'm Ok with that, although not really able to navigate according to component references on a schematic. I took the boards out to pass to the guy who checked out the caps, then put them back in. Although I understand that T60's are tricky to work on, I'd be happy to try anything within my limitations.

[Enzo]

Oh... That won't work. Unless your guy has an amp to put them in, l he can do is measure their capacitance. But that tells you little about leakage at voltage. I don't usually suspect caps for hum, honest, but it happens.

[Kidderman]

That's what he did (measure for capacitance). He doesn't work on guitar amps. I have a multi-meter, so could possibly make other checks if that might help isolate the problem.