@BU he may need to load the appropriate driver plus test program for the card and play with mute/unmute, the mixer, and all the corresponding audio settings.
Similar thing with my Xonar AV (which is most likely the predecessor, but wait, what's the exact version of the card anyway ?)
It's a shitshow configuring the multiple audio outputs on the Asus card, especially with the new Windows stuff.
Recommended DAC from my side: Cambridge Audio Dacmagic 100. Inexpensive, and works most of the time, also has good quality output.