why am I hearing electrical drain at shut off?

My dad is using a Classe Multi channel amp wich I bridged for 3 channel use, the left surround speaker has a not harmfully loud sound, but a sort of electrical drain sound at shut down that I can hear from 30 feet away, why is this in only one channel? Any ideas would be great, I am not feeling that this is a red flag fatal issue, but it shouldnt be happening...thanks Chad
Lift the lid and see if there is a small value like 250K resistor going to ground from the power supply caps.

DO NOT TOUCH THE CAPS, it likely won't be fatal if you do, but it would be a life experience you not likely forget.

There are caps dumping in that channel. You must have a bleeder resistor to ground in parallel with the supply caps to stop that from happening. My guess is you should be looking for 5.6k or so and it should have a big and fat 5W body. There should be at least one for each phase of each channel. "Why is it in only one channel" is a very good question though. It could be that you have a bad ground on that channel's board - if it's designed that way. You can also check the grounding scheme by measuring the resistance from the IEC socket ground pin to the chassis (find an unpainted location). If it is chassis grounded (< 100 ohms), I bet you have a black wire that is loose on the left channel board. If not, you will probably need a schematic.... Feel free to ask me questions if you need more info.

When you say "you" bridged it, did you just flip switches or did you rewire it?

thanks guys, no it is just a switchable bridged amp