EMI Noise Mitigation

[Scepsis]

First, to start off, my audio chain: I have a pair of PreSonus Eris 5 studio monitors connected via a pair of unbalanced TRS cables to an SM Pro Audio Nano Patch Plus (for convenient volume control/mute functionality) connected to a Schiit Audio Modi 2 DAC via a pair of unbalanced RCA to TRS adapters and a pair of unbalanced TRS cables (to provide signal to the whole shebang) which is then connected to my PC via a USB cable (duh).

 

The whole, four-part chain goes: PC -> Modi 2 -> Nano Patch Plus -> 2x Eris 5s.

 

The problem is, whenever I play a game, I get mildly audible EMI noise through my speakers that varies in pitch and tone depending on the current framerate that whatever game I am playing is running at. When the framerate goes up, it gets higher in pitch and changes tone. When it goes down, it gets lower in pitch and changes tone. (This can make for some really wacky sounds whilst playing a game in which FPS varies wildly) The speakers are dead silent at all other times.

 

I already know this: it is not coil whine. It is not 60 cycle hum. It is not a ground loop. It is not an issue with any part of my audio chain besides the PC to DAC link. I'm assuming the root cause are my two SLI'd 780s based on the fluctuation of tone and pitch with the framerate.

 

I did some research and came up with two possible solutions:

1. A glorified USB hub by Schiit called the "Wyrd." (It's supposedly helps with this sort of problem by supplying clean, well-regulated power to the DAC.)

2. A USB filter by iFi Audio called the "iPurifier." (It's an inline filter that supposedly sifts out EMI and electrical noise from the USB connection.)

3. A combination of both. (I have a feeling this will solve it.)

 

Do you guys think any of these options will work? Do you know of any other way I could eliminate (or at least significantly lessen) the EMI noise?

Your help is greatly appreciated as I have been fighting this issue for weeks now and am out of options besides spending even more money on my audio setup.

[NannerBeans]

A USB cable with a ferrite bead might help if you don't have one of those already. 

[Scepsis]

@NannerBeans

Would the ones you put on the cable yourself work?

[NannerBeans]

@NannerBeans

Would the ones you put on the cable yourself work?

Maybe? Not sure. 

[Scepsis]

Worth a try I guess...

[Scepsis]

@EmoRarity

Either suggest something helpful or leave the thread... just don't bolster your postcount via trollish spam. <_<

[EmoRarity]

@EmoRarity

Either suggest something helpful or leave the thread... just don't bolster your postcount via trollish spam. <_<

Why does post count matter? 

[Scepsis]

*facepalm*

[SSL]

Personally, I would just get the Schcheiit Wyrd.

[Scepsis]

@SSL

Yeah... I'm gonna try the ferrite beads and if that don't work, than the Wyrd will be the next step.

[EmoRarity]

Personally, I would just get the Schcheiit Wyrd.

100 quid for a hand full of capacitors and two mosfets, werf. 

[SSL]

100 quid for a hand full of capacitors and two mosfets, werf. 

 

I don't see the problem.

[EmoRarity]

I don't see the problem.

I suggest spending it on Audioquest cables instead, proven to be better. 

[SSL]

I suggest spending it on Audioquest cables instead, proven to be better. 

 

Obvious snake oil, Schiit isn't that at all. nwavguy toadie?

[Scepsis]

I suggest spending it on Audioquest cables instead, proven to be better. 

I know we had an argument about what constitutes snakeoil in audio, but Audioquest cables are the Monster cables of the audio world... :rolleyes:

 

Overpriced cables aren't gonna solve a problem originating within the traces of my motherboard.

[EmoRarity]

Obvious snake oil, Schiit isn't that at all. nwavguy toadie?

Man, I wanna ride that dick so bad. 

I know we had an argument about what constitutes snakeoil in audio, but Audioquest cables are the Monster cables of the audio world... :rolleyes:

 

Overpriced cables aren't gonna solve a problem originating within the traces of my motherboard.

Is that why you are interested in buying snake oil? If an external dac has not fixed the issue, a power cleaner isn't either

[SSL]

Man, I wanna ride that dick so bad. 

 

That's what I figured.

[Scepsis]

Is that why you are interested in buying snake oil? If an external dac has not fixed the issue, a power cleaner isn't either

Do you know this for a fact?

 

Bad USB power does indeed affect DACs in a negative way and my SLI setup is only exacerbating the problem and creating more EMI. If the issue lies there, then the Wyrd will at least help.

If the problem lies within the datastream, then the iPurifier should help as well.

 

The combination of those two options in tandem with a few ferrite chokes will hopefully solve my issue, which you are not helping to fix. At all.

[ShearMe]

You say it's not a ground loop, but in my experience that's exactly what this is, the loop being more prone to EMI interference than the rest of the audio chain. Using a DAC with optical to/from the PC has solved this issue for me in the past. A ground loop isolator (in the audio chain, not on the power cords) has worked for others. I suspect the iPurifier and Wyrd are "fancy" isolators with extra snake oil.

[creatip123]

I'm not really following, because I'm guessing there are some posts that got deleted.

 

My suggestion:

 

1. If you're using front USB jacks on the casing, try using the back ones. Front ones are known to have some problem with grounding. 

2. If you're sure it's grounding problems, then try using those USB with ferrite core cables

3. "power conditioner" aren't high end things, and not so hard to do. You can even built one like this:

 

Source: http://diyaudioprojects.com/Tubes/6DJ8-Tube-Headphone-Amp/

 

That one is for plugging straight to AC. You can imagine it should be much less complicated when using USB's DC. 

[Scepsis]

You say it's not a ground loop, but in my experience that's exactly what this is, the loop being more prone to EMI interference than the rest of the audio chain. Using a DAC with optical to/from the PC has solved this issue for me in the past. A ground loop isolator (in the audio chain, not on the power cords) has worked for others. I suspect the iPurifier and Wyrd are "fancy" isolators with extra snake oil.

I don't think its a ground loop because whenever I unplug my DAC from my PC all noise ceases. If I plug my Note 3 or my iPod 5th into the DAC there is no noise either. I dunno. I bought ferrite chokes for my USB cable in hopes to eliminate the interference. Maybe I should pick up a USB ground loop isolator as well.

*shrugs*

 

I'm not really following, because I'm guessing there are some posts that got deleted.

 

My suggestion:

 

1. If you're using front USB jacks on the casing, try using the back ones. Front ones are known to have some problem with grounding. 

2. If you're sure it's grounding problems, then try using those USB with ferrite core cables

3. "power conditioner" aren't high end things, and not so hard to do. You can even built one like this:

 

-snip-

 

 

Source: http://diyaudioprojects.com/Tubes/6DJ8-Tube-Headphone-Amp/

 

That one is for plugging straight to AC. You can imagine it should be much less complicated when using USB's DC. 

One post was deleted by the mods I presume...

 

1. Nope, rear USB.

2. I ordered snap on ferrite chokes for the cable and will see if they help when they arrive.

3. I have zero experience with circuits and soldering... so yeah, I'd just rather buy something.