Hum issue - driving me more crazy

Make sure the cables are plugged in all the way.

Dan_ed

If you are going to lift the ground (cheater plugs) try to do that on the preamp and let everything ground through the amps. >>>>>>>>Will try but I think this worsens other hums

If you haven't already, try to plug both amps into the same outlet and see if the hum is diminished.>>>>>>NO help

Matter of fact, you may need to plug everything in your system into one outlet to see if this helps even more.>>>>>>>>Will try

Try swapping the ICs between amps and see if the hum follows the change. >>>>>>No help

When you can, try turning off all of the breakers in the house except the one feeding your system and see what happens. >>>>Have tried without obvious source as I recollect but will try again

Jea48

*How long is this IC cable? >>>~ 15'
*What type of cable supports are used under the floor? Plastic? Metal? >>>>>>>>Blue flex hose supported with plastic hangers
*How often is the cable supported, distance between supports?
>>>>>>>>About 5' apart as I recollect
*What is the area, space, under the floor? Basement? Crawlspace?
Space is under entire first floor of house ~ 1800' I guess
Room is 15X20 -sort of isolated from other parts of house Crawl space is ~ 18" dirt to bottom of rafter

Magnumpi205 - > I don't disagree and will try this
Shayl123 - I have -> no help
Rwwear -> I have -> no help

BUT I replaced right channel with balanced IC's tonite AND SO FAR NO NOISE. Can even use the dimmers in room that were clearly problematic. Able to remove the cheater plugs without hum (which was an issue before)

Not ready to declare victory (as there was variation in level of hum) but things are looking up so far.

MAGIC SO FAR

Has the system always hummed or did it start when something was changed?

Hello Imdoc, Hope my obsessively detailed response was helpful in your quest to rid the hum. I am a firm believer now-a-days in running things balanced. Took years of trial and error, and a whole hell of alot of gear, cable, and subwoofer swapping. But balanced is the thing for me.

A suggestion for you regarding balanced cables. Before you go out and start dumping your hard earned cash on stuff, try some "professional" grade stuff. For whatever it's worth, I don't have any idea how $90 balanced mic cable from Guitar Center can be referred to as "professional", but I tried some of their "house" brand balanced cables, and also some MOGAMI brand. Didn't set me back much at all, and worked just fine for a long time, (until eventually upgrading to shit that cost 40 times as much for the same length.) Try it out. If it doesn't work out, or degrades your sound at all, you won't feel suicidal for for emptying your bank account. That cheap stuff ain't all that bad sometimes.

As for lights on dimmers- Elizabeth is oh so right. Not all dimmers are created equal, with some of them really causing more problems than they're worth. I have 800 watts of halogen lights on tracks, illuminating various pieces of artwork in my listening room. I too had hum because of them- once. Not anymore. Lutron, and Leviton make something called a (I KNOW I will screw up the spelling on this, but...) Colloidial coil?? something like that? It's essentially a "anti-buzzing" coil that is wired into your electrical supply line, between the dimmer and the fixture, lamp, etc. Works like a champ and completely kills the buzz caused by dimmers, and halogen bulbs. Lamps Plus sells them, or at least they used to. Try your local electricians supply house.

Unplug any cables (RCA, F connector, etc.) from your Cable TV/Sat/Antenna and see if the humm disapears.