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Suggestions for fixing interference issues

post #1 of 2
Thread Starter 
Hello everyone,

I've been having some issues eradicating interference from my computer audio setup. As of now, I'm using my desktop computer and a 30" CCFL-backlit computer monitor to play games and perform other tasks. For audio, I have a Fiio E07K connected to the desktop via USB, which I have then connected to a sound mixer via an RCA - 3.5mm connection. The mixer then provides a signal to 2 KRK Rokit 5s over short XLR cables. All these devices are connected to the same power strip, which is in turn connected to a grounded UPS.

The problem I've been experiencing is actually twofold. Firstly, I found that whenever my monitor was turned on and the backlight was on, I could hear a ton of interference/hum through the speakers, regardless of the output level of the computer. I ended up marginalizing this problem by removing the ground pin from the monitor's power cable (which had the most profound effect) and the second thing I did was increase the E07K's volume output to max and its gain to +12dB. At this point in time, I cannot determine a difference between when the monitor is on and off.

My second problem is slightly more troublesome, and I'm not really sure how to fix it. Whenever I'm doing something GPU-intensive and the graphics card has ramped up in its utilization or power consumption, I can hear interference that is almost definitely caused by the graphics card. I get different styles of interference based on the scene the GPU is rendering in the video game, I can hear interference when I move my mouse cursor around on screen, and when the GPU is being utilized at 100% by Folding@Home or a mining program, I get a constant hum from the speakers.

I've been considering getting a ground-loop isolator for ~$13 from Amazon so I could isolate those channels coming from the DAC, but I don't know if that would help. Does anybody have any suggestions for me on what I could try or what I could buy? I feel like this must be a common problem when connecting a PC to a stereo system, so I'm hoping that maybe other people have run into this issue and know how to fix it! It's really frustrating to not be able to listen to audio without a great deal of interference, and I'd love be able to fix it! thumb.gif
Big Mini
(20 items)
 
  
CPUMotherboardGraphicsRAM
Core i7 3770k @ 4.6GHz ASUS Maximus V Gene EVGA GTX 680 16Gb Patriot Viper @ 2133MHz 
Hard DriveHard DriveOptical DriveCooling
256GB Samsung 840 Pro SSD 500GB WD Caviar Black Lite-On Blu-Ray Burner XSPC Raystorm 
CoolingCoolingCoolingCooling
XSPC RS120 Swiftech MCP655-B Swiftech MCR220QP EK 680 Acetal/Copper block 
OSMonitorKeyboardPower
Windows 7 Ultimate 64-bit Shimian QH300 30" (2560x1600), ASUS VS238H-P 23... OCN Ducky with MX Blues Corsair AX760 80+ Platinum 
CaseMouseMouse PadAudio
Fractal Design Arc Mini Cyborg R.A.T. 7 OCZ Behemoth Logitech G35 Headset, 2x KRK Rokit 5 
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Big Mini
(20 items)
 
  
CPUMotherboardGraphicsRAM
Core i7 3770k @ 4.6GHz ASUS Maximus V Gene EVGA GTX 680 16Gb Patriot Viper @ 2133MHz 
Hard DriveHard DriveOptical DriveCooling
256GB Samsung 840 Pro SSD 500GB WD Caviar Black Lite-On Blu-Ray Burner XSPC Raystorm 
CoolingCoolingCoolingCooling
XSPC RS120 Swiftech MCP655-B Swiftech MCR220QP EK 680 Acetal/Copper block 
OSMonitorKeyboardPower
Windows 7 Ultimate 64-bit Shimian QH300 30" (2560x1600), ASUS VS238H-P 23... OCN Ducky with MX Blues Corsair AX760 80+ Platinum 
CaseMouseMouse PadAudio
Fractal Design Arc Mini Cyborg R.A.T. 7 OCZ Behemoth Logitech G35 Headset, 2x KRK Rokit 5 
  hide details  
Reply
post #2 of 2
    I believe the problem is that at least one device in your audio equipment setup is grounded, which is causing the audio signal from your PC to be referenced to your PC's noisy ground instead of the USB sound device's clean ground.  If you can disconnect that device, or if you have something you can use to temporarily disconnect the AC ground line to your audio equipment, you could verify that this is in fact the case.  If so, a ground-loop isolator should help.
My desktop PC
(14 items)
 
  
CPUMotherboardGraphicsRAM
Intel Core i7-3770K Gigabyte P67A-D3-B3 NVIDIA GeForce 8400 GS  1x Corsair 8 GB 
Hard DriveHard DriveHard DriveOS
Kingston SV300S3 WesternDigital WD10EZEX Samsung HD154UI Windows 7 Ultimate SP1 x64 
MonitorMonitorKeyboardPower
Daewoo L947BK Gateway FPD1530 HTK-2001 Dynex DX-400WPS 
MouseAudio
Kensington K72400 Realtek ALC889 
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My desktop PC
(14 items)
 
  
CPUMotherboardGraphicsRAM
Intel Core i7-3770K Gigabyte P67A-D3-B3 NVIDIA GeForce 8400 GS  1x Corsair 8 GB 
Hard DriveHard DriveHard DriveOS
Kingston SV300S3 WesternDigital WD10EZEX Samsung HD154UI Windows 7 Ultimate SP1 x64 
MonitorMonitorKeyboardPower
Daewoo L947BK Gateway FPD1530 HTK-2001 Dynex DX-400WPS 
MouseAudio
Kensington K72400 Realtek ALC889 
  hide details  
Reply
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