So it is probably one source connected to your system causing the hum. I know it is a pain, but I suggest disconnecting everything and methodically plugging things back in beginning with the Denon and then the 7700 until the hum appears. The idea is to isolate the piece of equipment that is sensitive to hum or where the hum originates.

One additional thought, and this depends upon your skill level with electrical (and daylight!), you might want to check the grounding in your dedicated circuit. If you don't like or are familiar with electrical I'd hire an electrician to check your electric panel, outlets, etc to make sure everything is ship shape. A good electrician should be able to diagnose and repair a grounding issue that may be the cause of the hum in your speakers.

And lastly, its generally not the amp that is the problem, its the way our electrical components are hooked up that causes the hum.

The home is only 9 years old, and I am pretty sure the electrical system (panel, circuit breakers, etc...) are good. I do have a small yellow tester that has 3 lights on it; you plug it in and it tells you if the circuit is good, ground in wrong location, etc... and that is showing the outlet/circuit is good.

Either Tuesday or Weds (when I have an hour or 2 to dedicate the time) I will unplug everything, then slowly start plugging stuff back in.

What I meant by do all amps have this problem, is what if I had bought a Rotel, or NAD, or Krell.....do they exhibit this hum? I also notice there are minimal "hum" posts for the Outlaw 7200. Is that amp not as prone to this?


A question on the Ebtech HumX If I get one, do I plug the HumX into the Power amp outlet on the Monster Power 2600, then plug the 7700 into the female end of the HumX?

AvFan's recommended test is definitely the place to start. I've had problems like this in my system that resulted simply from unruly cable management (power cords to close to speaker cables or analog interconnects), but other common causes have been dimmer switches, light fixtures, or appliances dumping "noise" back onto the house electrical service - often with no proximity to the home theater equipment.

Any system is at potential risk of this sort of problem, no matter whose equipment you use. As for the 7200, it's still potentially subject to this - the 7200 forum may simply not have much mention of it because there may be fewer 7200's sold than 7500's and 7700's.

Did some troubleshooting today;

* Unplugged the TV and sub, still have hum (SHH).
* Pluuged the amp into a different circuit, SHH.
* Unplugged all AV gear from Monsterpower 2600, SHH.

* Checked the grounding of the outlets, good.
* Unplugged all AV cables one at a time, and BINGO!

HOWEVER, the one plug that seemed to possible be involved was a digital optical cable feed fromm DirecTV HDTV Tivo. When I unplugged it, the hum went away for about 2 seconds, then reappeared. Plugged it back in, and it went away for 2 seconds, then reappeared. Unplugged, went away for 2 seconds then reappeared. Pretty consistent.

BAd for me, as the Tivo unit does not have an optical out. And right now I dont have another optical cable to swap. So, off to the store to get another.

I am crossing my fingers its a bad cable.

Odd that an optical cable would be the problem. Are there any other cables between the Tivo and the Denon that might be part of the issue?

I checked each one. What I think is weird is why would it go away when I unplug it, then reappear 2 seconds later?

This was a "quick" check as I did not have a lot of time. Tommorow I will unplug everything completely. Today I only had time to unplug, listen, and plug that cable back in (my cables arent labeled).

The only inputs I am running into my receiver are a CD Jukebox (analogue audio), DVD Jukebox (HDMI directly to the TV and coaxial audio to the receiver), the DirecTV Tivo (Component video and optical audio), PS2 cables (analog audio and component video), and a B & O turntable (analouge audio and a ground wire to the receiver).

Believe me, I am going nuts!

I generally look at TV related components long and hard. My experience, not all that extensive though, tells me TV stuff is a prime opportunity for a grounding issue to expose itself because they often use different grounds than the house electrical. I wonder if there might be a ground problem somehow being routed via the analog video from the Tivo to the Denon. I agree with Gonk that optical cables shouldn't (but it could!) be the problem; everything is plastic. You may have tried it but does disconnecting the component video cables between the Tivo and the Denon stop the hum? Otherwise I'd start at ground zero (everything is unplugged) and start adding components until you get the hum.

Weds night, 10:40 PM Update;

Everything is unplugged from the Denon. I have the Denon and 7700 connected using RCA cables, and both are plugged into a monsterpower 2600.

I unplugged the monster powerbar 1100 that supplies the Sony 60" SXBR TV and 250 watt Def Tech Sub.

I would say 99% of the hum/buzz is gone. If I put my ear directly in front of the horn tweeters on my Klipsch RF7s, I can just barely hear a very very quiet buzz. This is tolerable.

Now I am about to start hhoking things up.

UPDATE 11:25 PM

I think I found the problem. I had a component video cable with analogue audio for a Sony PS2 that when I plugged in the left and right audio portion, the hum got louder.

I am still plugging items in, but I have the TV and sub on, and still only a very very faint buzz is still audible. If I am within about 3 feet of the speakers (left, right & centre) I can hear it, barely. I cannot hear it from the surrounds (Klipsch RS7s hanging high near the ceiling) unless I climb a chair and get within a foot of them.

WOO HOOOOOO !!!!!!!!!!!

It was those 2 cables; a bad digital coaxial and a bad PS2 cable.

Everything is up and running and sounds GGRRRREEAAT!

The hum/buzz I am hearing is very, very, very low. I may get an Ebtech HumX to see if takes it away, but I am very pleased right now!

Success! These can be real obnoxious problems to trace down, glad to hear you were able to resolve yours.