Ok.. here's something that I just noticed...

Today (or really recently) I've noticed a slight hum coming from my 755... I'm almost certain this is a new occurance... So I started turning off everything else in the house trying to figure out what's causing the hum... I decided to put it off until tomorrow since it's getting late... I turned off my 950 by hand and since my head was really close to my center speaker's tweeter I noticed that I can hear a local radio station for a few seconds while the amp is discharging....

So.. what could be acting like an antenna? The interconnects going into the 755 are shielded... It's running the center, surrounds and rear surrounds... the speaker cable going to the back speakers is all running up through the wall then down to the speakers... I'm kinda suspecting this is where it's coming from....

....is it possible this could cause the 755's hum?

And.. since I know someone is going to ask..

All the amps (sub included (and no, that's not causing the hum)) are running off a dedicated 15 amp line and breaker, plugged into a Tripp-Lite iso-Block (the one that mounts to the outlet) and then plugged into a standard 8 plug Tripp-Lite surge protector just for more plugs...

I think I may try plugging all the rest of the equip. into the dedicated line tomorrow and see if that changes anything...

No matter what anyone says, *all* amplifier transformers hum. Just whether they are loud enough to hear or not. You might have a "louder" (than normal?) one.

But just to be sure, not a ground loop? Your AC line is properly grounded?

You could be getting some hum through the interconnects from some other device that is not on the dedicated circuit, or a ground loop caused by differences in ground between the circuit the amp is on and the circuit the other equipment is on (if you are hearing a radio station in the hum, I'd think the former is more likely than the latter). Cable TV's always a troublesome one, too. An even easier possibility? Interconnects lying on power cords can pick up some weird stuff sometimes.

------------------
gonk -- Saloon Links | Pre/Pro Comparison Chart | 950 Review

I took care of my hum problem some time ago by putting all of my "wall-wart" power supplies on a dedicated power bar fed from a ground loop isolator (ie. an isolating transformer - or 1:1 AC transformer.) For a hundred bucks you can get one that will be rated high enough to feed lots of low-current components. (The transformer is heavy and runs "hot" all of the time so take care as to where you put it.)

If I did not have wall-warts, but still had a hum problem, I'd probably use the transformer to isolate the pre-amp - in your case the 950. After that I'd keep trying different compoents - and combinations thereof. (However you'd have to buy one heck of a big transformer to handle the needs of a power amp - not even sure if one's available for home use.)

Certainly won't hurt to try such a transformer - and most electrical supply stores will let you return the transformer if it does not do the trick.

Jeff Mackwood