Quote Originally Posted by mikmas View Post
The theory is that standard USB cables (freebies) also carry the 5v voltage line ... even if its not needed. Taking out that line means that any interference/noise carried by the power line disappears with it (or is reduced)
How can line voltage noise be passed on via the DAC which is designed to decode a digital signal 1's & 0's, the sort of interference you're talking about could in my view affect the signal, but not in the way you describe, if the signal could be read you would hear fragmentation of the sound, you won't hear background noise like you do in an analog setup because the DAC can't decode it.