I forgot about that box! Its a Schiit Wyred - not sure what it brings to the party, but I have an aversion to USB, so it puts my mind at ease slightly knowing its being somewhat cleaned up!
I do like the Valhalla, but I can only compare to running the HD800’s straight out of the mojo. Its a definite improvement. Most importantly it warms my hands up with in the depths of winter - it runs HOT!