Headphone Jack Buzzes with GPU Usage

[OzMartini]

I ran into a really weird problem, and I'm guessing it can be either the motherboard or the case's wires/panel. I have a Corsair 750D with an Asus Maximus VI and a GTX 980. For some reason, when I plug in headphones to the case's headphone jack, I get a buzzing noise when I'm doing GPU intensive tasks. I ran GW2 and had MSI afterburner on the side and listened. The volume of the buzzing noise literally increased with GPU usage, which I found very weird. Also, another minor case problem is that the power button LEDs stopped working on my 750D; not sure if this can be related to the buzzing noise.

Edit: This only happens with the front panel headphone jack, my speakers plugged into the back work fine.

 

[Cristi72]

Hello,

Dismantle the front panel and put it as far as possible from the case; if the problem still persists, there is a problem with the grounding of the connection wires (the USB ports must not share the same ground connection with the audio jacks). If the problem dissapears, try to re-route the audio cable in the case, as far as possible from the GPU and the PSU power cables.

 

[OzMartini]

Tried it and problem is still there. What do you mean by there's a problem with the grounding?

 

[Cristi72]

Tried it and problem is still there. What do you mean by there's a problem with the grounding?

Any cable used for transiting low-level signals must be properly shielded to reduce electromagnetical interferences induced by various equipments, and the shield must be connected to the ground. It seems very simple and straightforward, but it isn't: each kind of signal must have its own ground plane. Motherboards have at least three ground planes: the main ground plane, connected to the case through the standoffs (and further conencted to the mains earthing through the PSU), the digital ground plane, used for connecting the components (CPU, memory, GPU, various adapter cards, USB, storage, etc.) and the audio ground plane. The ground planes are connected with each other only in specific points, to reduce the ground loop effect.

In your case, the ground of the front USB ports must not touch the ground from the front audio ports (the USB metal body must not touch any of the audio jack metal bodies). Also, the audio jacks must not be touching the front panel. Try to disconnect the front USB ports from the motherboard and see if the problem disappears.

If even with the front USB ports disconnected you experience the same audio problems, it can be a defective audio cable (the cable shield got interrupted or is touching the case through a non-insulated area), a motherboard problem (sometimes it doesn't properly connect to the case through the standoffs, either because of a screw not tightened enough or by using a plastic standoff instead of a metal one), a PSU problem (the wires being too thin or a power plug not fully inserted), a GPU problem (one of the side effects of the so-called "coil whine") or even a monitor problem (cable or malfunction).

What PSU / GPU make/model do you have?

 

[OzMartini]

I unplugged both usb connections and it still made the noise, so I think I must've gotten bad cables in my 750D from Corsair. My PSU is an HX650 and GPU is and MSI 980.

 

[Cristi72]

I unplugged both usb connections and it still made the noise, so I think I must've gotten bad cables in my 750D from Corsair. My PSU is an HX650 and GPU is and MSI 980.

Tricky situation...

If you do have an old case laying around (if not, try to salvage a front audio block form a broken case), connect the front audio plug from it, to rule out the 750D cables / jacks (Obsidian are the highest quality Corsair case line; although possible, it's highly unlikely they would use a faulty cable or jack port).

Try to use only the headphones (disconnect the amplifier from the rear jacks), also connect the headphones into the rear jacks.

Are you using by any chance a VGA connection between GPU and monitor? The noise is related only to heavy GPU usage or when the image is very bright? Disconnect the monitor from the PC, see if the noise disappears.