Two reasons come to mind: 1. Your sound card may be truncating information that your other system doesn't.
Your main system is revealing noise (RF? Bad AC?) that the computer can't. 2. The sound card may be have pure DC as its power source. Ever notice how good a (relatively) tiny car stereo sounds? Many think it's due to being battery (DC) powered. Them's my two cents!
Your main system is revealing noise (RF? Bad AC?) that the computer can't. 2. The sound card may be have pure DC as its power source. Ever notice how good a (relatively) tiny car stereo sounds? Many think it's due to being battery (DC) powered. Them's my two cents!