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Ground Loop Hum - Partially Identified - Solution?

I recently added a new power amp (conrad johnson) to power certain speakers (fronts and zone 2). I run through a B&K AVR 507 for my HT processing and 2 channel.

I immediately noticed a ground loop hum upon installing the amp. I was able to rid myself of the ground loop hum by testing the old cheater plug route. Hum immediately disappeared.

Don't want to keep the cheater plug approach as it is just a band aid and not very safe. Is it safe to run a simple ground wire from my amp chasis to the processor chasis? This won't cause anything to blow up (you know what I mean), will it? The ground loop does not appear to be coming from any interconnects (tested by swapping out the ic's to check for this). While I know they carry/continue the loop, they themselves are not responsible for it.

Not sure how the Jensen piece works, any experience (I know a lot of people have this problem from time to time) would be greatly appreciated.
ckoffend
ckoffend OP
684 posts
 
I went to Radio Shack on Friday to get all sorts of adapters to try out to help me determine my problem. I figured I would go cheap with all the stuff I needed and then once determined I would address the problem with a sonically acceptable solution. Fortunately, the cable is not my problem.

FYI - Radio Shack has discontinued the part referenced as the CATV isolation transformer. Perhaps they will come out with a new one that is compatible with high def., that may have been the reason for discontinuing the part.
swampwalker's avatar
swampwalker
5,138 posts
 
there are lots of other vendors for ooax or catv isolation transformers. Google the term and you will get lots, from <$10 to $100 (Mondial Magic). Or you can mount two of the 75-300 ohm transformers that come with DVD players and insert into the Coax line and see if that helps. If it does, then go for one of the purpose built units.
bdgregory
1,715 posts
 
here's the part you want: Groundloop Isolation Transformer

I worked beautifully for me. $17.95 list, and they have it on special for $8.95.
ckoffend OP
684 posts
 
Bdgregory thanks, good link. Not my problem, but sure the link may help others find what they need. Looking at the specs it appears this should pass HD too!

Anybody have any experience installing the Jensen part that serves the purpose of addressing ground loops? Where/how does this get installed?
bdgregory
1,715 posts
 
Looking at the specs it appears this should pass HD too!
It does indeed pass HD.

As for your amp ground loop problem, I assume your CJ amp has a captive power cord. If it doesn't, PSAudio power cords have a removable ground pin. I use them for my amps. Chasis ground for the power amp is accomplished through the interconnects to the preamp.
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