Buzz between Marantz SR5008 and Mcintosh C2300

I might be uncomfortable doing a ground lift but given the Furman configuration, where would you suggest putting the cheater? On the C2300 at the Furman?
03-18-14: Tccaux

For a test only,.... on the plug of the C2300. Do no install a ground cheater on the AC feed power plug of Furman.

From your original post it sounds like you have some type of a ground loop that is causing the buzz. Could the buzz you are hearing actually be a low level hum?

AND, the problem is a low volume buzz in the sparkers - all channels. I've plugged and unplugged everything, plugged every configuration on the Furman and the only remedy is to take the C2300 out of the chain. No buzz SR5008 to the Sanders. No buzz in the 2 channel set up.

Somewhere in the chain of IC connected equipment a difference of potential, voltage, exists on the equipment ground that is connected to the chassis of 3 wire cord and plug equipment. You say in your original post everything is plugged into the Furman. Correct? To me the only other earth grounded source that could be the reason for the difference of potential, voltage, causing the ground loop buzz/hum is the shield on the TV Cable provider's CATV coax cable.

Just one scenario for the circuit path of the closed ground loop.

CATV coax shield to Cable TV box, receiver >>> through all IC connected equipment >>> to the C2300 out through the power cord on the equipment grounding conductor >>>> to the Furman power conditioner >>>> to the equipment grounding conductor at the wall receptacle >>> to the earth grounded service neutral conductor of your main service electrical panel.

IF the above scenario is the case temporarily disconnecting
the CATV coax cable from the Cable TV box will break the closed ground loop circuit.

No buzz SR5008 to the Sanders. No buzz in the 2 channel set up.

The Marantz SR5008 does not use a safety equipment grounding conductor. The AC power wiring inside the Marantz is double insulated. Worth noting though if a piece of equipment that uses the safety equipment grounding conductor and if the designer/manufacture of the equipment also connects the signal ground to the chassis with the safety equipment grounding conductor, when said equipment is connected to the Marantz by ICs the case/chassis of the Marantz becomes connected to the safety equipment grounded equipment.
Jim

Very helpful all. Thanks for the responses. I won't be able to test until this weekend so I'll report back with results.

Theo, I have disconnected the C2300 and the buzz goes away in the other channels.

Jim - Yes, I'm pretty sure all is connected to the Furman, even the cable box.

More info this weekend. Thanks!

Well, it was the PS Audio dac that was the main source of the gound loop. I put a cheater on the C2300 and the buzz decreased. I added a cheater to the PS Audio and it went away. I haven't tried removing the cheater off the C2300 since I'm feeling good about NO buzz!

Now, all I have left to figure out is why the power trigger from the SR5008 is constantly on which keeps the C2300 powered on in passthrough mode. I have to unplug the mini plug from the SR5008 to power down the C2300. Been through all the menus, even disengaged all trigger on's on the SR5008. No difference.

Thanks again for the suggestions! Much appreciated.

Tccaux

Tccaux,

Just curious, did you try disconnecting the Cable Company's CATV coax cable from the cable box and see if that stopped the hum? If not all you did was break the ground loop circuit by installing two ground cheaters in the AC mains safety equipment ground.

IF the ground loop problem is being caused by the Cable Company's CATV coax cable that means the lightning protection grounding block on the outside of your house may not be properly grounded to the main grounding system of your home.

If it is the CATV coax cable causing the ground loop problem this will also break the ground loop and stop the hum. It will not correct the CATV coax cable grounding problem though.
http://www.amazon.com/Jensen-VRD-1FF-Digital-Isolator-Jensen/dp/B00AQV04FE

Should have mentioned that. Interestingly, the coax is also going through the Furman. I disconnected the coax at the wall and the buzz did not go away. I by-passed the Furman direct to the SR5008 and buzz remained. I'd previously checked the cable ground to the main grounding and it visually seemed properly connected. Am I missing other possible confirmation to eliminate coax as source?

Many thanks