[nicholars]

I have gone from using SPDIF coaxial to Async USB on the NAD D1050 DAC, I have ordered a better usb cable which may or may not make any difference, is there anything else I can do to optimize the USB connection to get the best possible audio quality? I am just using the USB port on my motherboard but it seems to sound slightly worse than the coaxial spdif from my Xonar STX, is there anything else I can do to ensure everything is working properly and to reduce and potential noise or jitter from the USB connection? Thanks

 

[PleasantSounds]

You're not mentioning anything about your player and it's configuration, and that could have some impact. If you're not doing that yet, try using a player that supports WASAPI (i.e. f2k, jriver) and configure it so that WASAPI is used.
Also, not all USB ports will perform the same - try them all.
 
As far as the physical connection is concerned, you could try using a USB cable with the power lines disabled - that should reduce or even eliminate the noises carried over from the PC. This works on many DACs that have independent power supply (i.e. not through the USB), but I'm not familiar with your model enough to guarantee that it will. Your call...

 

[nicholars]

  You're not mentioning anything about your player and it's configuration, and that could have some impact. If you're not doing that yet, try using a player that supports WASAPI (i.e. f2k, jriver) and configure it so that WASAPI is used.
Also, not all USB ports will perform the same - try them all.
 
As far as the physical connection is concerned, you could try using a USB cable with the power lines disabled - that should reduce or even eliminate the noises carried over from the PC. This works on many DACs that have independent power supply (i.e. not through the USB), but I'm not familiar with your model enough to guarantee that it will. Your call...

 
I have foobar set up with WASAPI and I think I have all the options correct, Was also wondering if making sure the DAC is not sharing USB bus with anything else is important, but I think my motherboard (asus Z97-A) only has 1 USB controller as haswell CPU the USB is on the CPU?
 
I swapped my cheapo 3m standard USB cable for a QED graphite dedicated audio USB cable and it certainly seems to have removed the grain that I was noticing through USB compared to SPDIF, pretty sure I am not imagining it, grain in sound was annoying me over USB, but don't notice any with the new cable just sounds clean like the spdif coaxial cable.