Thanks for the responses.
I bought the unit used so break in shouldn't be an issue. But I will give it time, maybe it wasn't used much. The Lumin u2 mini improved greatly with time.
I am using it with a Schiit Yggdrasil.
No power conditioner. Decent cables but not real high end. But the Lumin and the Aurender both sound great with this setup. I was thinking maybe the Lumin and the Aurender somehow did a better job filtering the ethernet, in which case a filter would help?
I am sure I could get better cables, switches, routers etc. but since the Lumin and Aurender both sound great I really don't want to go down that road.
These are all being used with a Raven Audio Blackhawk which has never been a bottleneck with anything I have used so far.
Thanks for the tips on tweaking the sound. Tried low latency, didn't seem to make much of a difference , I will also try the other tweaks,
Maybe it is just a bad system match or just my particular hearing proclivities.
Thanks ro all who replied.