770 and fixing the CATV ground loop hum

I received my 770 last week, and after a weekend of listening, I'm very pleased with my purchase. I was using a Denon 4802r (which is now my pre-pro) which has a pretty good amp section, but the improvement with the 770 is quite significant.

My one complaint was that I was getting a pretty bad ground loop hum caused by my cable TV connection--disconnecting the coax from the wall cleared up the problem, but obviously wasn't a long term solution. I had a bit of trouble finding a ground loop isolator (as mentioned in the troubleshooting guide in the 770's manual); the few I found online were on sites I didn't find too trustworthy, and an employee at a local electronics store told me I was crazy to be looking for one...

In any case, Blue Jeans Cable offers a RF Isolation Transformer that fixed the problem for me. Since I had trouble finding one, I thought I'd give them a little free advertising and hopefully help out others who run into this problem.
http://www.bluejeanscable.com/store/rf/rfprices.htm

I solved this problem differently:
I had a powerstrip with surgeprotection lying around, and it also has a coax-cable surge protection feature. I use the powerstrip for all the components, put the coax-cable through it and the hum problem disappeared. Therefore, I assume that the coax cable is connected to the mains ground somehow or other within the powerstrip.

I solved the problem rather cheaply. See my posting below (solving the ground loop hum) by using to inexpensive connectors that converts 75 ohm to 300 ohm and back again. I had both lying around the house.

John

I had exactly the same problem. Couldn't get a ground loop isolator from anyone in Houston at the time. I eliminated it by plugging the amp into a seperate surge protector. It worked, even though both surge protectors (the one for the amp and the one for the rest of the equipment) were plugged into the different outlets in the same recepticle. Go figure.

Voom guy was here today and now - for the first time - my speakers are humming! I unplugged the satellite cable and viola! What is the little Radio Shack Doohickey? Just ask for a connector?

it is called a "ground-loop isolator"

I see the ground loop isolator but I thought I saw on these threads somewhere where they sell a little adapter of some sort that you plug the cable feed into and then plug that into thesSatellite. box. I just can't find it. Would that sort of thing accomplish the job and what is it called?

Ok. I fixed it. I just ran the cable through my Monster 2500. I just love the Voom installer

Andyw,

Thanks for your link to BJ Cables. I ordered the Ground Loop Isolator, and it worked great.


Wingnut,

I have the monster HTS2000. I connected the TV Cable through this bar and most of the humming was eliminated. However if I pressed my ear to the speakers, I could still make out the hum. The Ground Loop Isolator completely eliminated all hum.