I'm using it fine from a USB 3.0 port, you need to set the USB connection in the settings to DAC mode, not MISC mode.
Also, i maxed the volume from the player before plugging in. Not sure if that helped.
However, not sure if this is just me but i'm having a delay when using it in USB DAC mode. Like when i play a song, there is a delay before the DAC generates the signal. Not sure if it's a firmware issue but i hope it will be fixed. The delay is acceptable when you are just listening to music... Though for me personally i tend to use my DAC for everything on my com, gaming etc - where having a delay in your audio can mean a lot in a competitive environment.
I'll let it burn in for a while and see if anything improves. Doubt it's my com problem cause everything works fine with my DACport LX.
I have this problem as well. I have set the delay to "short delay" on the USB side, but there is still a noticeable delay, which is a little annoying because it is enough to cause people's lips to desync from their speech when watching videos.
I suspect this is because the "delay" setting has some crazy some latency for buffering.
I am also using it fine from the USB 3.0 and USB 2.0 port.