Gotcha. So your setup is like this now ? ISP provider router -> Switch -> Streamer (audio server) via USB -> Mutec (Mutec uses external clock - Ref 10) -> Mutec Optical out to DAC.
From what I know so far, SPDIF and AES/EBU are essentially the same but AES/EBU is built for long runs of cables in high EMI environments. So in a home system, why don't you just try SPDIF itself ? In some cases, some DACs have better AES input stages. That is probably why many listeners find AES to be better on some dacs. If your dac has a great SPDIF input stage, you should try it.
In my DAC I prefer the optical input from the Mutec. Sounds more precise and quick for some reason.
I had tried the DIgi Coax with a Van den Hul cable but didn't really fancy. Sounded a bit "slow" ...
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