[rampilici]

Hello guys,
 
For some time I'm dealing with a huge problem, regarding sound input (microphone), on my PC. I've scrolled thousands of pages of Google and tried several fixes, but none worked. So, I came over this forum with hope that someone can help me. 
 
I'll start with some specifications and what is not causing the problem.
The audio card is an Asus Xonar D1, placed in a PCI slot, between the PSU and GPU (power suppy unit / video card). If it helps, the video card is an Gigabite GTX760 2GB, and the PSU is a Sirtech High Power 500w bronze, wih 80+ certification.
Here is an image with the PC, if needed: http://i.imgur.com/uWlewh3.jpg
The cable that is coming out from the audio card is the front panel connector for headphones and microphone.
 
The problem is NOT caused by faulty sound card drivers.
The problem is NOT caused by faulty cables.
The problem is NOT caused by faulty PCI slot (tested on two, one next to PSU, one next to GPU).
The PC is grounded (connected in a grounded power outlet).
 
The buzzing sound seems to appear whenever the system is in load (example: whenever running something demanding, like a game). 
The buzzing sound doesn't seem to appear (or it's so low that I can't hear it), whenever the system is in idle, or not doing something demanding (like browsing internet).
The buzzing sound is there no matter what input the microphone is connected to (either front panel connector, or in the audio card itself). 
The buzzing sound is there no matter what microphone is connected to the input line.
 
Here is a recording: https://www.youtube.com/watch?v=q7UIgdk_A2A
The buzzing sound is so loud that it literally covers the game audio sounds.
 
Is here somebody that can help me regarding this issue?
 
Thanks!

 

[DrKC]

Don't be too quick to rule out those things that you mentioned that were NOT a problem.  Interference problems can often be a combination of things.  It sounds as though the source of interference is being radiated in lieu of directly coupled.  Your mention of the level increasing when the computer is active reminds me of a problem I had with interference.  It turned out to be the monitor - not the computer.  When the screen was static, there was no interference.  When the screen was changing, updating, etc, the interference level rose.
It could be as simple as the mic cable lacking sufficient shielding and the monitor radiating noise.
The use of snap-on ferrites (of the right MIX number) on the monitor cable and moving the monitor or mic as far away from each other might be a good next step to try.
Good luck with finding the source - it can be a real challenge.  I've been through it many times since I've had my ham license.  You can easily get misdirected by false assumptions.  Don't assume anything while you're troubleshooting.