[Hemanse]

I have asked around a few places and thought i would give it a go here, got an annoying problem when i connect my headphones to either my DAC (nuforce udac-2) or just directly into my motherboards onboard audio, when i got nothing playing (music or a video) there is this feint hum or rumble in the background, not sure how else to describe it, but its just there, it does not raise or lower when i turn the volume up or down, its always the same, if i touch my pc or the dac the hum/rumble seems to go away.

Others have suggested that it sounds like a ground loop, i live in Denmark in an apartment which was build in the 50-60s and all the sockets just have 2 prongs like this http://i.imgur.com/S07jeMI.png and there is no way of getting my outlets grounded basicly, someone then suggested getting an usb isolator or a powered usb hub, which might fix the problem.
 
Thought maybe someone in here could help point me in the right direction, I work with PC's, but when it comes to audio i gotta admit i am quite clueless and this problem is kinda driving me crazy

 

[manywelps]

Ground loop Hum eliminator?: http://www.bhphotovideo.com/c/product/365781-REG/Ebtech_HUM_X_Hum_X_Ground_Loop.html
 
It's 3-pin though, and I don't know how it's wired internally