Whining noises - coil whine, grounding issue or?

Gooeybloof · Post by **Gooeybloof** » Fri Jan 16, 2009 6:09 am

Hi all,

yet another lurker coming out into the open... Like so many others, I have been used this great site to put my silent build together, with great success - thank you SPCR!
I have however run into a problem that I have not been able to Google my way through, so hoping for some help from the experts.

The problem:
After having eliminated most of the noise from my PC by slowing down the fans, I am now left with a very annoying high-pitched "electronic" whine.
The sound begins when the graphics card is loaded. It will vary in pitch when the mouse is moved or other tasks are performed.
A very similar (or maybe identical) sound is heard when using the front audio jacks, effectively rendering them useless.

I'm thinking that this might be a grounding issue, as the plugs in my flat have no ground installed.

Is there something simple that can be done to get rid of the noise?

jhhoffma · Post by **jhhoffma** » Fri Jan 16, 2009 7:54 am

It's coil whine, which generates the EMI your hearing in your audio jacks. The only half-ass fix for the actual noise is to cover the offending coils in hot-glue to keep them from vibrating so much, but probably won't do much to fix the EMI in the audio jacks.

But I would try to find a way to ground your system if at all possible. Maybe try to connect a conductive wire from your case to a nearby water pipe (that goes to the ground) would be able to help you determine if grounding is an issue.

protellect · Post by **protellect** » Fri Jan 16, 2009 8:22 am

Adding/using a different sound card can fix this, I believe

Gooeybloof · Post by **Gooeybloof** » Sat Jan 17, 2009 3:58 am

Assuming the noise in the jacks to be amplified coil whine as suggested by jhoffma, I tried to create my own shielding of the internal audio cable connecting the mobo with the front audi jacks. I first wrapped the cable in aluminium foil (which is conductive), then put insulation tape on the outside to keep the foil in place and avoid a short-circuit. I also re-routed the cable so it would go as far as possible from the gfx.

Didn't work

So either:
1. my home-made shield is not working or
2. it is not EMI that I'm hearing.

I'll see if I can borrow an audio card from a friend and test with that.

Monkeh16 · Post by **Monkeh16** » Sat Jan 17, 2009 4:30 am

Do you use a mic with the front ports? If not, disconnect the mic pins and see what happens.

Auroa · Post by **Auroa** » Sat Jan 17, 2009 1:28 pm

I have the same front panel audio problem with the same mobo (EP43-DS3L). I also get the whine from the video card being stressed (Radeon 3850 for me), but it's barely audible and easily ignored. The same can't be said for the front panel audio whine.

Mr Evil · Post by **Mr Evil** » Sat Jan 17, 2009 1:55 pm

It's probably not the wire to the headphone socket that's picking up the noise (n.b. simply wrapping something conductive around the cable wouldn't do much anyway, it needs to be grounded), but the analogue circuitry in the sound card itself. On-board sound is notorious for this due to cheap construction. High quality sound cards are usually good enough.

However, the best solution is to not have any analogue circuitry inside the noisy PC case at all. You can accomplish this with a USB sound "card", or by taking SPDIF to an external device.

Gooeybloof · Post by **Gooeybloof** » Mon Jan 19, 2009 5:39 am

Mr Evil wrote:
However, the best solution is to not have any analogue circuitry inside the noisy PC case at all. You can accomplish this with a USB sound "card", or by taking SPDIF to an external device.

Yeah, I actually had an external sound card on my previous PC chosen for that exact reason. But Vista broke it.

If Auroa has the exact same issue, the problem must be with the mobo. So suppose the only way to go is to get an external sound card.

Gooeybloof · Post by **Gooeybloof** » Fri Feb 13, 2009 7:41 am

I finally got a new sound-card (Asus Xonar DX in case it matters).

The problem with the front output is not solved, the whine is still there. Maybe a little better, but definitely still there. It appears that this was not a sound issue - but at least I now have vastly improved sound quality from the rear connectors compared to on-board sound.

I ended purchasing a mini-jack t-splitter and an extension cord for the headset. So now I can run both the hi-fi and the headset off the "front speaker" connection at the back of the case.

Overall, this works for me, although it's not what I had hoped for when I set out.

madhorsefuzzy · Post by **madhorsefuzzy** » Fri Feb 13, 2009 8:37 am

I suspect the PSU Enermax Pro82+ 425W.

I have the same PSU on a system I'm building and the PSU emits a buzzing noise when the power cord is connected and the PSU is ON or OFF or the computer is started.

The buzzing can be heard only if I sit near the PSU with my ears pointing directly to the PSU, so if I stay in front of the computer I cannot hear it.

To amplify the coil whine start the ATITool 3D window.

Whining noises - coil whine, grounding issue or?

Whining noises - coil whine, grounding issue or?

Conclusion