ive been noticing a vibration relatrd noise coming from my amp intermittently. It is not an amplified noise (it doesn't come through the speakers.) the amp is a Odyssey Khartago++. It seems to happen after warmup. About a minute of buzzing then back to normal for hours or days. I've also left it on continuously as recommended, and it still happens occasionally. Now this may sound crazy but I've noticed that sound several times when someone is in the kitchen. When water is running! Maybe an appliance (garbage disposal in sink) or microwave is on the same line? Could that be possible? The buzz comes from the left rear of the unit.
The A/C transformer is located in the left rear corner on this amp. You could try and tighten the bolt that secures the transformer to the chassis. This quieted down a buzzing transformer for me once. If that doesn't work, you might also call Klaus at Odyssey.
It's possible that an appliance on the same circuit could cause it. Can you try another plug on a different circuit?
You may have DC on the line causing the toroid to become physically noisy. It happens more than we notice.
Thanks for all your replies. All outlets in the room are on the same circuit. I have a set of QuietLine devices that I haven't used in this set up. Do you think it would help to place these in the circuit at various points. I have four units.
You live in a private house? I had the same issue when my old boiler fired. As already mentioned, the cause is likely DC on the circuit. The amplifier transformer is vibrating / buzzing
Assuming you don't have an electric hot water heater. The clue for me was water usage . Hot water Boiler / Furnace firing dumping DC on your amplifiers electric circuit.