Ground Loop Video and advice.


http://s1343.photobucket.com/user/fkmc123/media/IMG_1696_zps39c20b57.mp4.html

Any idea why this would be happening and a solution to fix? The two interconnects are L/R RCA's coming from my receiver to a Preamp. The power cable is from the preamp to a Richard Grey 1200C. Any time the power cable is not touching the two RCA's there is a ground loop. Or if I touch the RCA's the loop stops but not all the time. I've tried lifting the Preamp, with no change.

Thanks to anyone who can help.
767400
From watching the video and reading your explanation I think one of your Interconnects has a broken connection on the Ground or Return side

With the power cable resting on the ICs ... it pushes the return wire and makes contact with the IC’s shell and is grounded

When you lift the power cable the return wire is pulled away from the shell and causes an open which you hear as that buzzing

Rest the power cable back on top of the ICs and it pushes the return wire back just far enough to make contact with the ICs shell and the buzz goes away

Pick the power cord up and tapping the ICs shows an intermittent problem ... when you tap and apply pressure to the ICs it pushes the return wire back in contact with the ICs shell and the ground is complete and buzzing stops until the wire opens up again and the buzzing returns

The pressure of the power cord resting on cables and or the tapping of the cable both complete the circuit by pushing return wire back in contact with the ICs shell or ground point

I think you have a bad Interconnect with a broken solder joint on the ground or return side

Try replacing the interconnects with another pair to see if that solves the problem
.
From watching the video and reading your explanation I think one of your Interconnects has a broken connection on the Ground or Return side

With the power cable resting on the ICs ... it pushes the return wire and makes contact with the IC’s shell and is grounded

When you lift the power cable the return wire is pulled away from the shell and causes an open which you hear as that buzzing

Rest the power cable back on top of the ICs and it pushes the return wire back just far enough to make contact with the ICs shell and the buzz goes away

Pick the power cord up and tapping the ICs shows an intermittent problem ... when you tap and apply pressure to the ICs it pushes the return wire back in contact with the ICs shell and the ground is complete and buzzing stops until the wire opens up again and the buzzing returns

The pressure of the power cord resting on cables and or the tapping of the cable both complete the circuit by pushing return wire back in contact with the ICs shell or ground point

I think you have a bad Interconnect with a broken solder joint on the ground or return side

Try replacing the interconnects with another pair to see if that solves the problem
.
Try another pair of RCA cables. There might be an intermittent short in the cables that only manifests itself in certain positions.
Well when I previewed prior to posting I could see the video. Sorry, I'm new here and can't figure this out.
OK, try number two.

https://www.youtube.com/watch?v=d2XG_6L377g
A broken, open, signal ground return connection on an IC would be my first guess. Can you check the ends on the ics?
I'll start swapping one out at a time and see what happens.

Thank you.
Solved! The "R" AUX RCA input jack on my C-2200 is bad. The short is inside the barrel somewhere.

Now the next question. Does anyone have a good repair place for McIntosh's, preferably in the South East?

Thanks.

For Authorized McIntosh Service, use your zip code in this Service Locator.

You should be able to use another input. If AUX was used for HT bypass, then you would need to change HT bypass in the preamp's setup menu to the other input selected.
If you can't find anyone local, I would try Audio Classics in Vestal NY. Its one of the best places for McIntosh repair.
Fantastic! Thank you guys for all your help.
Solved! The "R" AUX RCA input jack on my C-2200 is bad. The short is inside the barrel somewhere.
06-12-14: 767400
I would bet the C-2200 uses RCA jacks that terminate/solder to a circuit board on the back of the unit. Good chance the bad RCA jack has a cold solder joint/connection.
Jim