3 Dedicated lines into 1

cheater plugs on every component except for your preamp. that cures 99% of all ground loop problems. saved me.

All of these helped but I think the remaining noise is because the amp and Monster are on different circuits. Does anyone think combining these circuits to be on the same line would help?

Yes that can be a problem due to unequal length grounds of multiple dedicated circuits causing a ground loop hum. Experiment by trying everything on a single circuit & see (hear) what happens.

First thing to do is take the monster out and plug all componets into dedicated lines, then take a cheater plug and use on amp only, should solve your problem and if it does reconnect everything back into monster.
Cheater plugs are crap so a better thing to do is to modify a dedicated power cord for amp. most of the time it's one componet that cause the hum so you may need to swap the cheater plug around until you find the componet thats causing the hum but most likely it's the amp.
Good Luck!

Jsawhitlock,

Is it safe to float the ground on a huge amp?

Anyone?

Yes, it would be the same as a cheater plug, as I have to do this with a Acurus amp 250 watts. I have multi acurus amps in my HT set up and they all hum so I droped the ground on the power cords and all quiet now, so much better than the crappy cheater plugs!
Another thing to do is check out your sub panels ground, take a volt tester and see if you have any voltage on the ground, may be something leaking voltage and causing hum. I had a Audio research LS-3 preamp that gave me hum so I dropped the ground and no hum.
Only drop the grounds on eq. that hums.
Good luck!

so wait - do you just clip the ground off of it with a pair of bolt-cutters?

this is f-n funny-i put in 2 more(1 already) dedicated lines sunday to try and solve a loop issue.one mono amp still sang a tune like this -hummmmmmm-well i grabbed a cheater plug out of the junk cabinet and now i'm finished.
called the amp builder and he said cheater plug was ok.
how long does it take new breakers, outlets and 12 ga wire (12 ft run) to break in --lol-- i noticed my sub amp likes its new home over the old line that it shared with lights and stuff.

I put a cheater on my amp and now have quiet operation. I am still nervous that the amp is somehow not protected. Is there any downside to floating the ground?

Bundy,
Take the cheater plug out and modify a power cord and improvements will be better! Drop the ground on the power cord. Happy Listening!

Bundy,
Since no one is answering your question, here are a few links to read. I'm not saying not to float the ground, but it's good to understand the situation before doing it.

1. On personal safety, see Gs5556's last paragraph in this:
http://forum.audiogon.com/cgi-bin/fr.pl?htech&1048100875&read&3&zzlPorschecab&&

2. On the fact that currents may appear on the component chassis (equipment dependent), are measurable, and may cause noise and hum:
http://db.AudioAsylum.com/cgi/m.pl?forum=general&n=56922&highlight=dedicated+lines&r=&session=

http://www.jensentransformers.com/apps_wp.html (see the downloadable paper on Hum and Buzz in Unbalanced Interconnect Systems for general floated ground discussion)

3. On equipment safety: I don't know of any problems, but you can take the advice above and check with the manufacturer.