Thanks for the shootout. Axis was one of my favorites.
Make sure that when you do these tests, that the USB DAC or USB converter is powered from the same AC circuit as the computer that is driving it. Otherwise the common-mode noise can get in the way of the performance. One way to reduce this noise is a USB cable filter, but even with this you should power them from the same circuit:
http://www.empiricalaudio.com/products/short-block
Steve N.
Empirical Audio
Make sure that when you do these tests, that the USB DAC or USB converter is powered from the same AC circuit as the computer that is driving it. Otherwise the common-mode noise can get in the way of the performance. One way to reduce this noise is a USB cable filter, but even with this you should power them from the same circuit:
http://www.empiricalaudio.com/products/short-block
Steve N.
Empirical Audio