All of a sudden, my amp is noisy

[phyfe]

Got a Workingman 12. All was well, but one day I turned it on and there was a noise. It's that typical background amp noise, 60 cycle hum kind-of-a-thing. Not bad, wouldn't be noticeable live, but it wasn't there before. Something has changed.

Bass plugged in, nothing plugged in... noise is the same. Gain doesn't change the noise, but it does go loud and soft with volume knob (which is at 10, BTW).

In the real world, I'm probably being a bit picky, but it wasn't there at all until recently. I'd like to fix it.

Tried plugging in the amp with a 3 to 2 adapter (ground lift). No change.

Any ideas?

Thanks!

[BeJay]

Sounds like filter cap in the power supply and / or a diode leaking.

[BassmanPaul]

Sounds like it's tech time before anything gets worse.

[phyfe]

Filter cap sounds right. Tech time sounds right, too.

Maybe after Christmas!

Thanks.