I had amp humm and initially thought it was the amp. Turns out, Toroidal (sp??) transformers are prone to this as a result of electrical interference. In my case, it was a halogen lamp on the same circuit as the amp. Turned off the lamp, away went the humm.
My current amps do humm slightly due to design, not a big deal though.
Regards,
My current amps do humm slightly due to design, not a big deal though.
Regards,