DSP doesn't create serious issues with SQ. Where do you come up with this stuff? How many AD and DA converters are you using that an external clock is needed?
Ethernet Clocking
i had previously reported that adding an Antelope 10m rubidium clock to the Etherregen results in major tightening of soundstage and location of individual instruments. To my great surprise adding filtering on the BNC 75 Ohms connection between clock and Etherregen results in substantial additional benefits. The filter used is a Mini-Circuits BLP-10.7-75+ DCto11MHZ model.
We are only beginning to understand how to maintain clean clocking on digital connections, it is of paramount importance to SQ.