Ground for Cable TV Hummmmmmmmmmm

Isn't it fun trying to isolate and eliminate ground loop hums. As you have probably read here before, the type of hum you describe is usually, but not always, related to the cable TV signal (assuming you have cable TV). The cheapest first solution is to go to Radio Shack and buy a ground breaker -- the Shack sells one for about $15. Try that first and see if it works. If that does not solve the problem, your problem may be with the interconnect cabling. According to one of the local high-end HT dealers, it seems that some IC's have a different ground configuration than others, and thus there may be interaction problems betweeen SOME IC's and SOME equipment. You may have to try different cabling to see if that solves your problem. The idea you propose may also solve the problem, but you might want to try the quick alternatives first.

Where the CATV enters your home, it should be connected to a "grounding" block. From the grounding block a #10 solid should connect to your grounding electrode. The grounding electrode is the rod for your AC serice entrance. Your telephone protector should also bond there.

To add to what Mrderrick said, it is apparently common for installers to ground the entry point of the cable system to whatever is handy. Breaker boxes, water pipes, gas lines, your neighbor's electrical system... I've seen all these done. If the desire is to fix the problem rather than patch it this is the place to look first.

BTW, I am NOT an electrician nor do I have any official training in this area. Before doing anything it is best to ask questions. This is electricity and the penalty for mistakes may be severe.

Mrderrick and Fpeel have it right about the correct fix. The problem is that the cable TV coax sheath provides an alternate ground path for the AC neutral wire if the coax ground is not in close proximity to the common AC ground point. The Radio Shack ground isolator should help in any case. From my experience it won't completely eliminate it but will knock the hum down into the system noise floor. In any case insure that the cable TV coax is grounded before it enters your house otherwise you have connected a potential lightning rod to your system.

Mondial (maker of Acurus and Aragon) makes something called the MAGIC for about $100. It works like a champ, but why not try the cheaper Radio Shack one first.

Check the jensentransformers.com website. It has a comprehensive diagnostic. But, to cut to the chase, chances are the ground loop is coming from the CATV line. Jensen makes a $50 isolation transformer for the CATV line that has proven to be $50 well spent for me. (No, I'm not affiliated with the company. I just happen to have spent a lot of time trying to solve a ground loop problem in my system and finding the Jensen product was a "eureka" for me. 'Sometimes it doesn't take much.) Good luck with it, Jim

Try this (it worked for me): run a wire from the outside connector of your TV cable (I had a wire with an aligator clip on it) to the ground on your amp. That Radio Shack "grounding block" is just a cable connector with a screw on it for connecting a wire. Using the aligator clip works just as well.

Ironically, just read about the MAGIC this AM in a review of Tishiba DVD palyer in stereophile (May or June 2001-I think)

I had a serious ground loop hum that I was able to isolate to the tv cable being the culprit. The only bandaid that worked was if I unplugged the tv cable altogether. I had electronics plugged into a 15 amp non-grounded circuit and others, including the amp, plugged into a 20 amp grounded circuit.

Moving all electronics over to the 20 amp grounded ciruit resolved my problem.

Call Tom Tutay of Transition Design. Your problem will be over.