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Posted By: Roidefromage The Ground Loop Beast is back - 05/22/09 01:40 PM
So, my Axiom sub is humming again... I thought I had solved this problem awhile ago, but after installing my new Oppo BDP83 (which I LOVE!!)it has started acting up again. I am going to try a cheater plug, but the Oppo already has an ungrounded plug. I am at a loss. I need advice about where to go next.
Thanks!
Posted By: BlueJays1 Re: The Ground Loop Beast is back - 05/22/09 01:45 PM
Hmmm. What type of connections have you hooked up to your OPPO?
Posted By: jakewash Re: The Ground Loop Beast is back - 05/22/09 03:13 PM
I suspect we have analog outputs hooked up to the amp and through this the hum is finding it's way back to the sub.

Did you solve the previous problem with Axiom's ground loop isolator? If not it is time to buy one.
Posted By: Zimm Re: The Ground Loop Beast is back - 05/22/09 04:04 PM
Is the oppo very near your AVR or pre/pro? If so, try moving it far away and see if the hum goes away. I had to replace a CD player near my AVR as it was creating a 120hz hum through my amp. New CD installed, no more hum. If your hum returned when the Oppo was plugged in, that is the first place to look.

Good luck, that noise is irritating!
Posted By: Roidefromage Re: The Ground Loop Beast is back - 05/22/09 04:29 PM
The Oppo is about 5 feet away and connect with RCA analog cables to the 5.1 inouts on my processor. The sub is connect with an axiom sub cable and a splitter that goes to my other sub. Forgive the ignorance, I'm more of an appreciator than a techy, but how do you set up an isolator? Oh, and everything is plugged into my power conditioner.
Posted By: jakewash Re: The Ground Loop Beast is back - 05/22/09 04:40 PM
The ground loop isolator is for the cable feed into the amp/set top converter etc. I suspect there is a poor ground for your cable/house and it is manifesting itself through the various RCA connections going into the amp and the analog connections on the player and making it's way back to the sub.

Try Zimm's idea, also try plugging the player into the same outlet as the rest of the system for a common ground, if all that fails, you have nothing to lose buy purchasing the isolator and giving it a try.
Posted By: Roidefromage Re: The Ground Loop Beast is back - 05/22/09 04:43 PM
Sorry to be so dense, but it says that the isolator is for my cable connection? How does that effect the sub?
Posted By: jakewash Re: The Ground Loop Beast is back - 05/22/09 04:57 PM
Some articles to read

http://axiomaudio.com/grounding.html

http://www.axiomaudio.com/tips_eliminate_hum.html
Posted By: JohnK Re: The Ground Loop Beast is back - 05/23/09 01:50 AM
King, if you did nothing but replace your old player with the Oppo, this wouldn't appear to involve a ground loop or other grounding related problem. If the connections still follow the same path there'd be no apparent reason for a ground loop to appear that didn't exist before. If this is the case, using a cheater plug, buying an isolator, or other similar procedures wouldn't be helpful.

Possibly the suggestion by Charles(zimm)about the new player causing interference directly through the air might have merit, although it's hard to believe that Oppo would design a unit with such a high interference potential.
Posted By: Zimm Re: The Ground Loop Beast is back - 05/26/09 05:01 PM
I had a cheap Sony DVD player (hate to fire up the PS3 just to listen to CDs) placed directly on top of my pro amp and that caused the problem. I'd be surprised if the Oppo does this, but given the large power supply in the amp, I thought maybe I was just subjecting some unprotected part of the Sony to EMF it could not deal with. An equally old - but much better - Panasonic A10 DVD player fixed the hum.

My explanation actually makes perfect sense if you have just the right right amount of knowledge mixed with a much higher level of ignorance on the subject. Try it! Works like a charm.
Posted By: Ya_basta Re: The Ground Loop Beast is back - 05/26/09 05:11 PM
\:D \:D
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