Audio Interference - Grounding Issue?

Klopek

Honorable
Sep 10, 2013
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10,510
I've pretty much solved this despite not really fully understanding the reasons why. Posting for information and a potential explanation.

My system was producing audio interference when under load. This was primarily GPU related, with the CPU comparatively producing very minor noise when stressed individually.

This interference was present whether using the onboard sound or a recently purchased Xonar DX. The HDMI port of the graphics card was producing perfect sound.

I noticed that the noise was present even when the audio jack was connected to an inactive port - i.e. connecting the jack to the onboard sound - even when disabled through the BIOS - resulted in the same interference.

While testing, I happened to notice that the issue had completely disappeared. Upon scratching my head for a while, I noted that the interference is completely eliminated (from the Xonar - didn't check onboard - presume the same) whenever my HDMI lead is plugged into the graphics card. This is whether the HDMI connection is active within Windows or not.

Does this imply that I have grounding issues with my system? This only works when the cable is connected to the amplifier on the other end, removing that causes the noise to return.


Other Notes:
Interference via the onboard sound was present when using a different GPU and even a different system case.

I've now placed the Xonar sound card as far away from the GPU as possible. Placing it side by side did introduce minor interference.

I've read that the Xonar DX is incapable of functioning without its additional power connector. This is not strictly true as it does work - it's just easily distorted.

System Information:
Asus P7P55D-E PRO (VIA® VT1828S 8-Channel High Definition Audio CODEC)
i5 750 @ 3.4Ghz
Powercolor AMD 7970
Asus Xonar DX
Fractal R4 Case
... etc
 
is the plug the pc is plugged into grounded fully? Does sound like a ground issue. Can you try plugging your PC into the same outlet as the receiver is plugged into, since that seems to kill the noise.