Mod CD/LD players with digital coaxial output - need help!

[Assyst1606]

Hi Mooly,
Thanks for the reply & the feedback.
I only hear the clicking sound when I’m near the DAC. I don’t hear them thru’ the headphone that’s connected to the DAC. I don’t recall hearing this clicking sound when my DAC is connected to a DVD player that has got a built-in coaxial digital output.
I think there’s some kind of latching going on, on the board inside the DAC.
I guess I’ll go ahead & mod the Kwak clock on my CD player while leaving this circuit (TTL to SPDIF) on my LD player.

[Mooly]

Hi,
You mean the DAC itself clicks ? not clicking on the audio output. That has to be a relay/s, nothing else would do that. The DAC perhaps does mute when it detects no "audio" in the data stream.

[dangus]

I suspect that although the resistors are in series, they do give an effective output impedance of 75 ohms, which is the correct impedance for S/PDIF coax.

As for the clock stuff... whatever oils your snake. I'd expect most DACs from the last decade or so should have some anti-jitter stuff built-in, like an ASRC (asynchronous sample-rate converter) (like that nice chip AD made that also acted as an S/PDIF receiver).

[Mooly]

Mea culpa

Never played around with clocks. I always feel the idea is sound, but could be let down in the implementation. If the new clock ends up a few centimeters away from its destination the overall result could be worse. Correct grounding of all the relevant parts that make it up become important to.

[dantwomey]

Here's an interesting link that discusses some of the SPDIF circuit options.

Regards,
Dan

[Mooly]

Nice link, thank you