2. home-theater
  3. 1395084824

Buzz between Marantz SR5008 and Mcintosh C2300

I've got a HT and 2 channel setup I'm trying to marry for use of FL and FR speakers on both.

2 Channel - Computer Channel D/Pure Music to PS Audio Perfect Wave MKII to McIntosh C2300 to Sanders Magtech 2 channel to Snell AIII's.

HT - HD cable/BlueRay/Apple TV/Webcast to SR5008. RR, LR, Cntr and Sub speakers (all Snells) out from the SR5008. FR and FL are Pre-Out (RCA) from SR5008 to C2300 Passthrough designated input. C2300 power triggered from SR5008 to engage Passthrough. FR and FL from C2300 to Sanders.

All are powered through dedicated 20amp line and then through a Furman Elite 20 conditioner.

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.

Thoughts? Is the SR5008 pre out to the C2300 just never gonna work? Just to much difference in the equipment configurations? Seems to me this how the C2300 Passthrough should work. Yes?

Or is this just the excuse I need to upgrade the low-end processor? :)

Thanks to all.
Tccaux
tccaux
tccaux OP
36 posts
 
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!
tccaux OP
36 posts
 
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
jea48
4,323 posts
 
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
tccaux OP
36 posts
 
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
jea48
4,323 posts
 
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?
03-23-14: Tccaux

I by-passed the Furman direct to the SR5008 and buzz remained.
Not sure what you mean. Remember the SR5008 does not use the safety equipment grounding conductor. The power cord that came with the unit is only a 2 wire cord and plug. The SR5008 can pass a ground loop potential, voltage, current from any RCA line input to any RCA output through the outer shell of the RCA jacks. All the signal grounds are common, connected together, in the SR5008.

Interestingly, the coax is also going through the Furman. I disconnected the coax at the wall and the buzz did not go away.
First thought if you disconnected the coax cable from the wall, there by breaking the connection from incoming CATV provider's signal coax cable, that would isolate the Cable TV from the rest HT and 2 channel audio system......
So if we assume the CATV is not causing the ground loop hum what is?

You think it is being caused by the PS Audio DAC . If that is true then you should be able to remove the ground cheater from the C2300 and still not hear the hum.

Edit:
[quote]"I'd previously checked the cable ground to the main grounding and it visually seemed properly connected."
[/quote]
Just curious, when you traced, followed, the ground wire from the CATV grounding block located on the outside of your house where does the other end of the wire connect to?
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