I prefer a neutral sounding interface with the PWD2. Hydra-X is warm sounding and the PWD2 itself is also slightly warm off neutral, which is fine. More than this I find it detracts from overall transparency.
USB to AES:
I also had the non PP Audiophilleo 2 with a linear regulated PSU for the USB power rail. It was great with the PWD2, but I marginally preferred the PUC2 as it proved even more resolving.
Edited by negura - 1/2/14 at 8:11am