XM
I could not wait and so I called about the 7700.
The mechanic's name is Frank. He told me that the 7700 has been running two days on and off. No noise. He ask me if I had the unit plugged into any other device such as a line or surge protector.
I said no that it was plugged directly into a wall outlet.
He intends to take a look at it internally later today.

Now I am really scratching my head.
Could it be the outlet?
The only other thing I can think of is that I do have a ground wire (that is not in use) right beside the amp. I have been to lazy to take it out of the PVC I have it running thru but it is laying very close to the amp.
I am going to work on it right now.

XM
There were two ground wires. One I just removed but the other one was from the 990 and I noticed it was disconnected. Could that have been the issue?

Sorry for all of these posts.
I just remember that I had the ground for the 990 disconnected b/c if I remember correctly I had a ground loop with it connected to the 990.

Going crazy.
Thanks...from the lunitic.

Don't get crazy...I think we all become anal about our systems; I know that I've have been super-sensitive about ground loop issues because it is a major bugaboo with high-end systems....and I originally had problems with it when I first set up my 990/7500 combo years ago.
As I've said several times in different posts on the Saloon, I'm pretty sure my amp "hum" issues are related to incoming power from the electric company "Grid". Lately, I have had no issues at all, for like 2 weeks. When I do get them, it is at a certain time of day (supper-time), and lasts intermittently for about an hour. That's it...everything is dead silent after that, for days on end. Although I did have an issue recently, and it turned out to be an old lamp, with a weird kind of bulb that was in another room (not even on the same circuit!).
In my eyes, these Outlaw amps are bullet-proof...I really believe your amp hum issue is a grounding/electricity thing; are you sure the Comcast line coming in is properly grounded?

If he doesn't find the problem, when you get it home plug it in and let it sit completely by itself for several days and listen for the hum. If no hum it is something else in your system. Sometimes it is hard to localize the hum and I find it useful to touch my stuff to feel if I can find the source. The same goes for speakers. Lightly touching the cones is more reliable than your ears as a gage.

Thanks guys for all of your support.
I must have made at least four phone calls to the poor guy who is monitoring the 7700. I had contacted Scott on more than one occasion about this issue and as you mentioned (jmacari) Scott referred to the issue as being the power grid at different times of the day and I imagine different times of the year. I believe that I had mentioned that up until recently there was no hum. I did have this issue last year but again at different times of the day and season. Sounds crazy but true. I had disconnected my entire system TWICE to find the culprit but only found myself to be more frustrated.

Comcast is connected both to a grounding rod six feet in the ground and also is plugged into my Furman. As far as I know this setup is correct. If not please tell me.

I will take your advice XM and plug the 7700 into an outlet and turn it on for a couple of hours and see what happens. I can also after I am satisfied that the 7700 standing alone is not humming reconnect the speaker wires and the balanced cables and then one at a time disconnect the rest of the equipment from the Furman.

I did ask Frank (repair man) if the issue could be from a bad receptacle but he said as long as the receptacle is wired correctly it would be a none issue. Receptacles work or they do not.

Will keep you up to date.

If the recptacle or its circuit is not going to the same ground plane as your 7700 it could be the problem. Try plugging into a separate circuit using an extension cord. I would also try removing the comcast feed to your system.

I started looking into my hum issues and have noticed a couple things that I'll post here in case they help others.

1. I started cleaning off my workbench so I could open up the amp and noticed something was making the same sounding buzz as my amp. turned out to be one of the compact flourescent lights in my shop. Turning off all CFLs in the house didn't make a difference so I started thinking there's noise on my power lines.

2. I built an RF sniffer probe and started poking around my system to see if there was any radiated noise.
Power lines : Nothing
975: Nothing
Amp: BUZZZZZZZ
I looked at the amp and the noise peaks out when the probe is by the transformer.

Conclusions: None. But either there's noise coming in through my power lines. (This is called conducted noise.) Or something is going on in the amp that is generation the noise. I need to do more exploring. I'm going to try a filter on the power input and see if that helps.

Here's how I made my test probe:

I took an old RCA cable and cut the connector off one end. I then stripped off about 5 inches of the outer insulation to expose the shield. I twisted the shield up and cut it to about 3/4". I then stipped about 3/4" of insulation off the center conductor. Loop the end you just stripped around and twist it with the shield. A little solder and a little tape and you have test probe with an RCA connector on the end. Make the opening created by the center conductor loop into roughly a circle.

To use it I disconnected the RCA connector comming from the 975 and plugged the probe into the RCA input of the amp. Use the probe like a butterfly net (only slower). The opening of the loop needs to face the direction you are measuring. I had the kid listen to the speakers as I move the probe around. She would let me know when the noise got louder or quieter.

Will do XM.
Tuesday will be a week. I will be calling about the 7700 early morning.
I do not think anything is wrong with the 7700.

Thanks EE

Ok...Today I called Frank about the 7700 at High Noon. He has had the 7700 since last Tuesday and has the amp on and off now since last Wednesday. He also did a routine inspection of the guts of the unit and found absolutely nothing wrong. His response about me asking about the inspection was that iI have a very well built amp. On my end I have made routine checks on all of my circuits with a meter that indicates if the receptacle is wired properly. I have a clean bill of health on the receptacles. Besides Frank told me that would be a non-issue with the problem I am experiencing. He wanted to keep the 7700 for one more day and since I was unable to pick it up today he is running it again for most of the workday.
Tomorrow I will be picking the up the 7700. I will be checking every piece of wire, connections and cable. I do intend to first disconnect the Comcast cable and take it from there.

So people wish me luck.
One more thing. If the cause IS from the Comcast cable what do I do to prevent the problem?

PS I will be unable to work on this until Friday. I do intend to work at it all day if I have too.
I will report on the update Friday at 5.

Thanks people!