Film-Tech Forum ARCHIVE: Grounding for analog audio cable

This is topic Grounding for analog audio cable in forum Digital Cinema Forum at Film-Tech Forum ARCHIVE.

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Posted by Tim OBrien (Member # 5605) on 05-19-2010, 11:17 AM:

I'm connecting a blu-ray player with RCA audio outputs to a CP650. I'm using the Odyssey breakout board and Gepco 6-pair cable which includes a signal ground and chassis ground for each channel in addition to a cable shield ground. The breakout board has separate terminals for signal ground and chassis ground. When I solder in the RCA connectors at the other end of the cable, are the signal ground and chassis ground joined together? What about the cable ground? I'm a bit new to this so thank you for your help!

Posted by Tony Bandiera Jr (Member # 2365) on 05-19-2010, 12:52 PM:

Hi Tim:

You would solder only the signal ground at the RCA end. Connect other end to signal ground at board.

Connect the chassis grounds at the breakout board ONLY. Float them at the RCA end.

Odds are you won't need to use the cable ground, but if you do it would connect to the chassis ground end of the breakout board only.

If you are still getting hum after all of the above, try connecting only ONE of the chassis grounds to ONE of the RCA ends. (I usually use the center channel for that if needed.)

If you are using the breakout board with the transformers on it you will not have any issues. The standard breakout board makes grounding and shield connections more critical.