Not to add to much to the clamoring horde, but I wanted to second this with a more specific angle.
I'm curious as to a comparison of its driving abilities. If the uDac didn't have quite enough muscle to really push some of the more inefficent cans (i.e. 300ohm Senns), is the HDP enough of a step up to make an audible difference, to act as an adequate substitute for a dedicated SS amp (like a Caliente?) I'm assuming so, but I'd like your opinion on this gap specifically, if you have the time to do so.
Power output: 80mW x 2 @ 16-Ohm
Headphone Output: 6.3mm headphone output jack drives headphones up to 600-Ohm (80 mW@600-Ohm)
Please address both situations. Thanks