I have multiple built in appliances in my house and thus could not unplug everything as you suggest. A previous suggestion was to turn off all the breakers except for the one to the stereo. Will this work as well as what you suggested?
Yes, but in the event it does go away, you'll be doing what I said to isolate the offender, anyway.. Either way.. will work for the test though.
Built in, I'm not worried about, too much. WHY. because you brought your noise with you, you've moved.. Not saying a common appliance isn't a problem.. chances are slim, though.. just saying..
I suggest an extension cord, only to get away from whatever is in the room. Turn all the breakers off including the room the stereo is in.
The room you choose turn back on and plug into. Make darn sure, nothing is plugged in, in that room, except the extension cord, back to your stereo..
After that only thing is drop the voltage down.. If It was a tube unit, we would have looked at possible noisy valves too.
Your getting there..hang in there. one way or the other...
Oh and BTW I bought a plane ticket to come fix it. My ticket is for Cancun Mexico... Oh you don't live there.... opps.. can you meet me there..LOL
Regards..