Ok, I just remembered something... A few months ago I bought this new PSU (the Kingwin Platinum) and when I had everything connected back and the system on, I was playing with one of the fans, which had a cable extension, which had the pins exposed. Guess what happened? I shorted something...

I just checked again: no noise in the headphones (I always keep them connected to the card output). I'm not sure what adapter you are referring to - I have the speakers connected directly to the outputs of the card via phono (RCA) cables. I'll try a different power outlet, but I lost...

Hi everyone, first post!   I have the same problem with the Xonar Essence: really strong EMI noise while watching video, less disturbing but still present otherwise. It starts when the card gets powered (after the click). The headphone sound is clean. I have a pair of amplified monitors...