Can i also point out my experience with the cheap £5-10 USB sound cards, with the mic & speaker jacks has been pretty poor, i think i had 3 eventually give up within a few months. I thought it'd be ideal for a cheap media player, VGA & USB sound, meant no video card and the sound cards were as much as a HDMI GPU so not worth considering. Unfortunately they were useless.
If they're a reasonably reputable brand or more than cheap chinese tat, you should be safe, and as mentioned they're recognised as a sound card when plugged in.