Discussion in 'Computer Audio' started by Fuzziekiwi, Dec 19, 2017.
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  1. Fuzziekiwi
    I'm getting static noises through my rear 3.5mm jack, plugged into my studio monitor speakers (unbalanced connection I know). It doesn't happen with multiple different headphones plugged straight into the rear jack.

    It also happens though but not as much noise using my external USB Schiit Modi DAC and Asgard 2 Amplifier combo, it's still there though if I turn the gain up through both my speakers and headphones.

    I tried moving cables around to see if that affected it, but it didn't. Everything is hooked up to the same power strip, could that be an issue, or is it the motherboard?
  2. NA Blur
    Does it sounds like a constant hum or buzz or does it sound like random noise consisting of random frequencies?

    If it is more like a hum then it could very well be a ground loop Try separating the grounds since you already have them together. Does your powerstrip plug into the wall using three prongs or two?
    Last edited: Dec 20, 2017
  3. Fuzziekiwi
    It's more like a bunch of little random frequencies, but consistent. It's a three prong.
  4. NA Blur
    Is the rear 3.5mm labelled? If so what does it day? What type of 3.5mm plug are you connecting to it?

    If I understand correctly you are trying to take the audio out from the studio monitor's amp and use it for headphones?
  5. NA Blur
    If you move your mouse around while listening to the noise can you hear a slight buzz as you move the mouse?
  6. Fuzziekiwi
    The rear 3.5mm input is green. I'm connecting a TS to RCA + RCA to 3.5mm converter. I want it plugged straight into my PC so I can use the sub input on the back of my computer to add a sub, but the noise is too much.

    Regardless the issue still happens in my modi schiit combo but quieter, so I'd like to see if I can get rid of that noise.
  7. Fuzziekiwi
    onevstheworld likes this.
  8. NA Blur
    How do you have your modi combo connected? USB?
  9. NA Blur
    Not sure if a ferrite choke or two would help, but it may reduce the high frequency noise going into the various devices.
  10. Fuzziekiwi
    Yes, USB.
  11. NA Blur
    Can you unplug all other USB devices and report back if if the noise goes away?
  12. NA Blur
    Just to be sure all power cables are plugged into the same power strip? Even the PC needs to be connected to the same power strip.
  13. WilsonT90
    Dirty pcb.
  14. NA Blur
    In the end it's most likely PC noise traversing down the USB cable and getting into signal path. Sometimes a better shielded USB cable does the trick. I'm surprised that using your modi combo does not eliminate the noise completely. The DAC in most if not all Schiit gear are pretty good and mine is dead quiet.

    Do you have a cellphone or even a wireless router nearby? Perhaps you're getting EMI from an external device?
  15. Fuzziekiwi
    Noise does not go away if I unplug all USB devices. I made sure the PC Monitor, PC, and amp are all on the same power strip. I tried plugging the amp into the wall, same issue. I turned off my PC and power supply and the issue was still there, although a bit less. Unplugged my modem and router, no effect on the noise.

    I ordered a sound card to see if it's just the mobo since I just ordered a sub and I hope that'll minimize the issue. I'm going to order better RCA cables/USB cable for my Schiit as I think that's the only thing that would minimize the noise too. I know I'm not supposed to daisy chain but until I buy longer cable powerstrips this will have to do.

    Here's a diagram of how things are wired:
    Computer Setup.jpg
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