General audio topics that don't fit into specific categories.
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Re: Using the same outlet not an option
Posted by Soundmind on March 15, 2005 at 12:15:03:
As I thought I said, IMO a star ground will not fix the problem. That's because there are multiple paths to a common ground point through each of the signal grounds where they interface the star. For example, the Preamp signal ground may connected to the safety ground at the preamp but also through the signal all the way to the subwoofer and then through the subwoofer connection to the safety ground. A panelette would not be necessary to create a local star gound, just tying the grounds together from the three outlets at the nearest common point possible and using the largest gage ground wire for them. This would ential replacing the 14/2 Romex with something heavier such as 10/3 Romex. (BTW, this would also entail bringing the home runs from all three circuits into the same junction box if they are on separate circuits.) This would not eliminate the problem but it would reduce it by reducing the impedence of segments of the loops.
Driving a new ground rod for a clean signal ground would be permitted because it will not ground the neutral at a second point. The neutral is grounded at the service entrance to the house. Redundant grounds of this type are permitted (I'm about 99.9% sure, any electricians in the audience?) The clean ground would then be used as a zero ground reference for the signals.
Another more drastic solution is to replace the AV equpment where the design floats the signal ground with respect to the safety ground. Equipment with balanced inputs always has this configuration. My Marantz 3800 preamp has this configuration but my HK Citation 11 doesn't. With the HK in my system, I had a ground loop due to using two different Cable TV outlets in the same room, one for my VCR and one for my TV set. When the audio signal was connected, it formed a ground loop. The solution in my case was to use only one cable TV jack and run a longer wire using a single RF input on the back of the set.