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Discussion Starter · #1 ·
Let me start by saying that my cable TV wasn't grounded at all. I had to add a grounding block, and check all of the connections to make sure that the fittings were properly installed (which most of them were not). So I was able to substantially reduce the hum to an inaudible level from the listening position, but I can still hear it when I'm close (less than a foot) from the speakers.


I know it's still the cable connection - I unhooked the audio cable from the cable box to the receiver and the hum was gone.



What can I do to completely remove it? Do I have to get an Isolator. If so, does the CISP work well?


Thanks
 

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Get a good quality power bar that has a cable in and cable out, and then plug ALL of your components into the same power bar. Monster makes a whole series of these, but there are others out there that may be better value.


Dave
 

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Get the damn cable company to ground it correctly! It's their responsibility.


Kal
 

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Discussion Starter · #4 ·
It is grounded correctly now. I ran the ground to the water main which is where the mains is grounded. I think it might actually be the cable BOX causing the problem now. The noise is gone when I remove the audio and video cables from the box to the back of my receiver. I have also tried using a cheater plug on my amps, and that didn't do anything.
 

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Discussion Starter · #7 ·
I tried plugging into the same outlet, but it didn't matter. I also ran a ground from the block directly to the electrical panel, and that didn't make a difference either. I'm totally stumped. I have checked and re-checked every cable and ground, and no luck. The only thing that works is disconnecting cable tv, either from the wall or from the box to my receiver.
 

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Like Dave recommended....I solved this problem by running the CATV signal through a surge protector that has coax in and out. I guess it lifts the ground.
 

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Generally a hum from the CATV is an indication that the cable system is not grounded correctly. Many times this is a result of the cable system not being bonded to the mains at the service entrance. All cable system elements including your antenna, splitters, switches, and cable grounding blocks should be bonded to the mains at the service entrance. A single point ground eliminates many of the hum issues. Your previous post suggests that at least part of your CATV system is bonded to your mains. Can you tell us a bit more about how this is done in your set up?


MT
 

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Discussion Starter · #11 ·
Everything is correctly grounded. I grounded CATV to the water pipe (which is where mains is grounded). I even went as far as to try running a ground from the grounding block to the mains panel ground. Nothing worked. I received a CISP unit yesterday, installed it ... and the hum is gone completely.


And I don't have any Monster stuff at all...
 

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Quote:
Originally Posted by bri1270
What can I do to completely remove it? Do I have to get an Isolator. If so, does the CISP work well?
Buy yourself a pair of 75 : 300 Ohm transformers like we used to use when connecting our Atari 2600/cable boxe/VCR to at old TV.


Connect them together with your cable on one side and equipment on the other.
 

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My installation field supervisor had recommended this, I generally get

the electricians back out to find out where the ground path had been

recently altered to cause the problem in the first place.


I tried this for analog cable in my home last night


and the results were nothing short

of remarkable. The analog channels were greatly improved in quality. I'm

going to order the Jensen and see if the results are better or equal.


I had previously installed a grounding rod for my CATV since I had

a ground potential problem about a year ago.


I'm going to hookup my HDTV cable box into this same HD ready

TV, and see if it the baluns pass HDTV.
 
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