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Marantz AV7701

I am experiencing horrible humm issues with my 7701 setup.
7701 is connected via XLR to 5 mono amps. Combination of Bryston and Wyred.
The 7701 when connected creates a humm noise independently of volume. The higher the amp gain and speaker sensitivity the higher the noise. I have a suspicion there is some wrong with grounding or what have you?
All units are powered and grounded via a BELKIN Power Unit.
Any ideas? I am ready to ship the 7701 back but wanted to get your input maybe i'm missing something...
Thx
tsulzbacher
tsulzbacher OP
1 posts
 
Folks, thx for the help.
I did unplug the HDMI Channel from my comcast HD box and the hum disappeared. Seems, like one of you said, an issue w ground looping.
I would imagine the big challenge now is to solve the ground loop - Other wise my cable box is useless more or less.
Ts
doggiehowser
672 posts
 
There are ground loop isolators you can buy. At least you've identified the problem. Maybe see if these isolators can fix the problem for you
tls49's avatar
tls49
1,351 posts
 

Here are a couple of choices for the ground loop isolator you need.

http://www.cs1.net/products/jensen_transformers/VRD-1FF.htm

http://www.mcmelectronics.com/product/DISTRIBUTED-BY-MCM-4170-/33-8700

They usually cost $25 and up, so the one at MCM is definitely cost effective, and the reviews are good.
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sodapop's avatar
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sodapop
16 posts
 
I am running my AV 7701 with a Parasound 1206 and experiencing the same Hum/Buzz that others are talking about. My friend bought a 7701 and connected it to an older Adcom amp and also experiencing terrible hum worse than mine. I bought a Theta Intrepid and am going to test it with that Amp and will report back. I am wondering if all 7701's have this issue if you do not use the matching Marantz amp? This is bad news.
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