HELP I think I have an electrical issue??

Tim,
I would confirm that the lines are indeed "dedicated". Did you do this, or did an electrician do it? Many times, electricians that I've spoken to, after hearing my requirements and specific goals, proceed to tell me how easy it will be to tap into this line or that line, not having listened, or understood what I meant by "dedicated line".
Electricians, like other professionals, seem to poo-poo the goals and the reasons for which they've been hired by a client. (I work in the medical field and see this often).
So check to see if your requirements have been met.
Good luck. Keep us posted.

Tim,
I am wiring a cabin right now and have been reviewing my electrical book with this issue in mind. The house curcuits are all tied together at the main breaker panel so spikes, surges and noise generated within the house can move between them. This agrees with experience in my current cabin. I wonder if making sure the dedicated line is on the opposite panel bus (110V leg) from your furnace or noisiest 110V appliances in general would provide the needed isolation, or if the neutral bus would still allow contamination of the other circuits. 220V appliances are connected to both busses so there may be no escape there. Also, the book says that surge protection mounted at the main panel will deal with spikes generated within the house. Is there a conditioner/filter that could be connected at the panel to deal with noise in general?

Could a common-ground explain the problem? Have you tried to lift the ground on the M60 Amplifiers?? Use a 2-prong adapter on each amplifier. It may improve the audio reproduction as well.

Well so far from what I have seen is that my dedicated circuits are both on the same side of the panel as the furnace is. I do have a gas furnace so the breaker for the furnace is 110. As a last resort I can look into putting the furnace breaker on the other side of the panel. (Is this what you were referring to Nosnhoj???)
Also one other thing to note is that my ground bars in my breaker are full and there is more than one ground in each one, including both dedicated circuits for my audio setup.

I have also switched my amps to the other dedicated circuit that is installed, and now the clicking noise the furnace starting is now coming through the opposite speaker.

Commcat,
So what if I use a 2 prong adapter and I find out that the problem is gone then how do I really fix this problem as I do not want to permanently use one of these adapters.

Oregon,

yeah, I actually did install them myself. by confirming the lines are dedicated, yes I believe they are.

I installed 2 20amp breakers, connected to each breaker is a run of 12/2 romex, then connected to a pair of hospital grade duplex's.

Like I said before all has been fine with my previous amps since I installed the 2 dedicated lines 4-5 months ago, and this just started yesterday when I hooked up these amps.

Tim