[PowerPaul86]

Hi there,
 
I use a Audio GD Compass as a DAC connected via USB to my Behringer Truth 2030A speakers.
 
After I upgraded my graphics card the speakers started to buzz, depending on the main color of the current picture and even the frame rate of games.
 

 
This setup doesn't buzz, when I connect it to another PC and as soon as I remove the DVI cable the buzzing is completely gone.
 
There is no buzzing, when I'm using Linux, which is the reason, I think, that the graphic card is the main culprit.
 
The whole system draws more power from the PSU, when the graphic card is working, so I'm not completely sure if it isn't really the PSU.
The PSU is a Corsair HX520W, which should be enough for this setup as I'm drawing around 320W 430W from the socket, when I'm gaming.
 
I'm currently using my Sennheiser HD 650 for gaming because of the high input impedance, which gives me no buzzing at all.
But I also want to be able to use my speakers, when gaming.
 
Did anyone else ever experience a similar problem with their USB connected DAC and quite sensitive speakers?

 

[mich41]

Sounds like some ground loop issue.

Probably the most "proper" solution is to use USB galvanic isolator (if disconnecting DAC from USB kills the buzz, it will work). Dunno where to get them in Germany.

A cheaper solution is to disconnect monitor (as it appears to be the source of this noise) from socket ground with some 2-wire extension cable, splitter, etc and leave the monitor grounded only through DVI cable and computer. It's kinda "less safe", but you will really have problems only when the monitor short circuits some high voltage to ground AND the DVI cable or computer power cable is disconnected AND you touch some metal part of the monitor at this time.

 

[PowerPaul86]

I resorted to plug a Creative Soundblaster X-Fi in front of the Compass and connect the two with an optical cable.
 
This way there are no more electrical interferences.