First, rip CD's using XLD to AIFF. Never use ALAC format. Second, install a decent playback software such as Audirvana, Pure Music or Amarra.
Finally, you may never get great sound using those interfaces. I've not heard them myself. You may need an upgrade USB converter or reclocker. The master clock in these interfaces is the most important part of any digital playback system, more important than the DAC itself.
More tips here (no advertising):
http://www.empiricalaudio.com/computer-audio/
Steve N.
Empirical Audio