Use of an external clock with an SPDIF DAC

[Dominique-T]

I need explanation from experts in the domain to understand what could be the interest to use an external clock with an SPDIF only DAC... My understanding was that the clock information was embedded with the audio signal in the SPDIF cable. So in order to make it works, should the external clock not be connected as well to the source?

Sorry if my question is stupid...

Dominique

 

[somebodyelse]

You're right - the SPDIF signal contains the clock information. A modern DAC should be able to extract it well, but this hasn't always been the case, and still sometimes isn't - see the jitter tests in the DAC reviews. The external clock has a good use in pro settings where multiple DACs and ADCs need to be synchronised. In hifi it's more likely to be there to appeal to a subset of buyers, but probably doesn't actually improve performance - see the Auralic Leo GX review for an example. In much older DACs, before the techniques for good clock extraction were widely used, a separate clock signal might have some genuine benefit.

 

[Dominique-T]

Thank you for the link!