Speaker buzz with SS amplifier, input disconnected

Did these amps have this problem from day one, or is this recent?

Do you have any other equipment near the amps that is on?

Do you have florescent lighting or light dimmers?

If you swap the physical position of the left and right amps, does the greater hum stay with the amp?

If you move one of the amps and speaker to another room, is the problem still there?

I'm trying to figure out if you might have electromagnetic pickup (radiated pickup). You can tell if it is radiated because when you move the amp around, the pickup will be greater or less.

Dimmers and florescent lights transmit higher frequencies that sound like buzz.

Power conditioning doesn't get rid of radiated pickup.

Possibly both amps are having electrolytic cap breakdown, but that normally happens one at a time on older amps.

Thanks for your thorough inquiries, Tom32.
The amps have had this problem from day one, for approx 2 months but is inaudible over the music...only between tracks etc.
Actually my equipment rack is removed from the amps and loudspeakers, with a 5 meter balanced IC between my VAC pre and Gamut M250 monos.
No fluorescent lighting or dimmers.
Yes, the larger hum stays with the amp and there is apparently no change with change of room (I used a monitor speaker in room #2 as the Blades are too big to move!
I think I will send them back to a Gamut for non warranty investigation/repair.....thank you to all respondents !

What I meant about moving it to another room was to see if a different AC branch of power or if a different electromagnetic environment caused a change. You should check everything before going through the hassle and cost of sending it back. Also the repair dude is going to be pretty puzzled if he gets them on the bench and can't find a hum.

But is sure does sound like a power supply hum to me.

Would you kindly expound on the type of layout problem which might result in this speaker buzz. Can a noisy toroid transmit buzz to loudspeakers etc

Generally a noisy power transformer will not cause noise in the audio path as well. But there can be AC line problems that can cause both noise in the amp and mechanical noise as well. Sometimes it can be confusing to sort them out.

The fact that one channel is noisier than the other is a clue. Without knowing any more about the amp I can't say more about layout, but that is what it suggests to me. IMO the amp should get checked out.

Ever get this sorted?