I have two computers with M-Audio Audiophile 192 cards, and a Yamaha LS9-16. One computer's S/PDIF output is connected to the LS9 S/PDIF input. The LS9's S/PDIF output is connected to the other computer's S/PDIF input. All three (along with some other gear) is behind a common power conditioner (and therefore on the same ground).

The LS9 is configured to use the clock off of S/PDIF input. This works great almost all of the time, but occasionally, there is a clock sync issue, causing the LS9 to drop out audio for a few seconds before regaining clock signal and moving on.

I have noticed this happening when plugging other devices into an electrical outlet, closing a door, and rarely when touching the metal side of a desk. This leads me to believe that a burst of static is just enough to throw off the clock.

How can I affordably remedy the issue? Is there some sort of isolator or something that will take care of the problem?

I understand that pulling clock out of S/PDIF isn't necessarily the best to sync to in the first place, but it is generally working for us, and I'd rather try to fix the problem rather than buying new cards that support a word clock input.

  • Sounds like some kind of ground-loop problem. I can't understand why they keep using asymmetric Coax-S/PDIF rather than optical or AES/EBU. Sep 9, 2011 at 22:53
  • What would be the source of the ground loop? All of the equipment is on the same ground (and even hooked up to the same power conditioner).
    – Brad
    Sep 10, 2011 at 0:04

1 Answer 1


This is a bit of an adventurous idea: try to set the LS9 as clock master and both computers as slave, split the S/PDIF with a well-shielded passive splitter and feed it to both computers, and just don't use the actual audio in computer 1.
S/PDIF is definitely not meant to be used this way, but it might still work.

  • Hmmm, I'll try it this weekend. If splitting it off degrades the signal too much, I might try taking the S/PDIF output of computer 2, and send it back to computer 1, clock from the LS9. I will let you know how it goes.
    – Brad
    Sep 10, 2011 at 0:00

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