Transformer hum?

>>Have you tried turning off everything in the house yet?<<

Yes. I even turned off the refrigerator. I have plugged
and unplugged, isolated, paired, tried with a component
plugged into the AC Conditioner tried with it plugged into the wall -- all different combos and one at a time. Still hums.

There is one dimmer switch on another circuit. But,
I had that light turned off. Could it cause a hum even
if it is turned off?

Man, I would love it if it were just a matter of replacing
a dimmer switch. On the other hand, I don't know how I
would explain to my wife that we can't have a dimmer in
the dining room. However, I could replace it just to
see if this is the cause -- at least I would have peace
of mind.

Sugar --

Thanks for the suggestion. I would eventually like
to have a few dedicated AC lines run so the amps can get plenty of AC. Why does the transformer hum if it is
working extra hard? Can you explain that further? Also, how does dirty AC make the transformer hum and why doesn't
the AC conditioner, BPT-3.5 -- eliminate the hum when
components are plugged into it?

Today, I tried using cheater plugs, but it didn't help.
I've been plugging and unplugging, isolating, trying
different combos, etc. etc. Unless the cheater plugs
need time to work, need to burn in or something, I can say that cheater plugs are not the answer. I do not have dimmers on this circuit. I have tried disconnecting
the TV cable. Didn't help. I don't know if I have mechanical hum, or not. It seems like a weird coincidence that I have 5 items in my system that
use transformers and four of them hum. I have florescent lights on a completely different circuit and when they are on, the humming is much louder. But when I turn off all the lights in the house, I still hear
a light humming coming from my components.
To add another wrinkle, one of my Levinson 436's
hums, but the other is stone silent. I have heard that
a ground loop hum can be identified by whether or
not you can you can hear it in the speakers. I can
hear it in one speaker, but not the other.

I suspect the electrical system, but I don't know
enough about it to know if I am on the right track,
or not. I was hoping the AC conditioner would solve
all AC problems, but it seems susceptible to whatever
is affecting the other components. Or, coincidence or not, I have four components that just happen to have
mechanical hum.

Does this information help?

Anyone?