Can (defective) PSU affect quality of sound card output?

[GUTB]

If the motherboard uses regulated power supplies I don’t think an unstable PSU would necessarily cause degraded quality in a soundcard, BUT if the PSU is generating a lot of noise that IS getting into the card than yes it could effect quality.

 

First try this experiment: plug your PC into another room’s outlet (that’s on a different circuit) with nothing else plugged in or turned on (lights, TVs, heaters, etc). Check sound quality. This will eliminate the possibility of something outside of your PC injecting a lot of noise.

 

Another thing to do is to MAKE SURE the Windows mixer isn’t screwing you over; make sure your players are set to exclusively control audio. You may have set that up in the past and something changed it back.