Electrical interference on ASUS Z97 Motherboard + Xonar DX Sound Card

[Terrum]

I am trying to lessen or eliminate electrical interference noise with my 10ft 3.5mm to 6.3mm cable. I have the 3.5mm inserted into my Xonar's Line In and the 6.3mm into my musical instrument.

I have tried inserting the 3.5mm into multiple places. The electrical interference still occurs when plugged into the onboard sound card, but the electrical interference DOESN'T happen when I plug the cable directly into my headphones (with the same cable, as my headphones have a female slot on them).

I tried other things too such as plugging my phone into the Line In port of my Xonar and onboard soundcard, but the electric interference still occurs on both of them.

The issue only occurs on Line In/Microphone of the Xonar, there is no interference on Xonar's headphone/speaker 3.5mm port, which uses a 3.5mm to RCA (the RCA goes into my speakers), and my headphones plug into the speakers.

I'm not sure what is causing the issue, but it's definitely - I have tried moving the cables as far away from electricity as possible and I have tried moving any cables and devices (my graphics card for example) as far away from the sound card as possible, but seeing as it's happening on the motherboard's onboard sound card too I can only assume it's an issue with the motherboard itself which is passing the same issue onto the Xonar sound card. Or maybe it's a driver issue?

Either way, I'm hoping someone can help and/or give some advice for what I could potentially try Many thanks for reading!

 

[jsmithepa]

Post a 10 sec .wav of this "interference."

 

[Terrum]

https/clyp.it/xyox0svr

 

[Cuthof]

As a comparison, this is how it sounds with interference from PCIe/24pin power cables running too close to front panel audio wire. Turn up your volume(The peak visible is Heaven benchmark stopping, not a loud noise but relative), and you'll clearly hear when the Heaven benchmark starts and ends(the very high-pitched and barely audible noise at the end is CPU, 24pin) - https/clyp.it/zlyaidbc
That is Essence STX II connected to front panel audio. With microphone recorder device enabled(front panel), you hear the interference above and it doesn't matter if anything is connected. With it disabled it is as silent as the grave. The interference is low in the Windows recording above but very audible in streaming, video capture or when using a microphone. Test by disabling any and all recording devices(speaker icon in taskbar, right click and select Recording devices), then if the interference goes away try isolate which one and where that connection is.