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How to stop USB noise in my DAC from my Laptop (mac)

Discussion in 'Sound Science' started by indigo bob, Jan 27, 2017.
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  1. Indigo Bob
    Hello,
     
    I have the FiiO X3ii and the Martin IMS HVA and have tried to use them as DAC's for my Macbook air.  
     
    But on both I hear a very high pitched humming sound constantly that takes away from the quality and listenability of those two devices.  Normally they would both have a quite clear or black background, but when plugged into my laptop using their DAC modes the background has this high pitched hum.  I plug them into my mac using a USB cable.  I have tried different USB cables, but that hasn't made any difference. 
     
    I have read that ground loop isolators may help...
     
    ... and I have also heard that firewire may help, but I don't know which avenue to pursue.  
     
    I am hoping to find anyone who has had this USB noise problem while listening to DAC's hooked up to their laptops or computers with USB connections and has successfully eliminated the usb noise and how.
     
    Thank you.
     
  2. castleofargh Contributor
    not a mac user so I can't really help. google returns quite a few problems with mac books and USB/firewire/OS upgrades. did you try removing all other external devices to check if there is any change? is the problem new? I expect you have checked basic settings and have the digital volume level close to the max on the mac.
    I could tell you to try plenty of stuff like a powered hub, some magical boxes like jitterbug, shiit weird... but that would be like injecting a sick patient with random drugs while praying to get lucky. if you can't diagnose the most probable cause, it's hard to tell how to solve the problem.
     
     
     
    else, as you might notice, the sound science section doesn't have a lot of views, maybe asking in another section might help.
     
  3. Indigo Bob

    Thank you for your response.  I might try another forum if this ends up being dry.
     
    I don't put the mac volume on max.  It's usually near normal to be honest.  I don't like to have the volume too high on one device.
     
    The problem is not new.  I have noticed it with the macbook airs.  I tested out a few of them and its the same thing.  I tested the macbook air with both my DAC's, the x3ii and the HVA and they have the same results.  It's just that high frequency digital audio sound.
     
    I was thinking of trying the jitterbug cuz I can buy it on amazon and return it.  It seems to get the job done for some people with a computer-DAC setup.
     
    What do you think?
     
  4. castleofargh Contributor
    I'm on principle against all those toys sold to do the job our devices should already do. but if you're curious and can use amazon, why not have a little fun[​IMG]. maybe there will be a good news at the end of it? not knowing what your problem is, there is no way to know if that little crap can help.
     
     

     
  5. pinnahertz
    How is the MacBook Air powered when you hear the noise?
     
  6. Arpiben
    @Indigo Bob
     
    In order to have a better idea of your system, please could you define it better:
    - MAC + FIIO X3 + IMS HVA + Headphone,
    - MAC + FIIO X3 + IMS HVA + Active/Passive Loudspeaker
    - MAC + FIIO X3 + Active/Passive Loudspeaker,
    - MAC + FIIO X3 + Headphone,
    - MAC + IMS HVA + Headphone,
    - MAC + IMS HVA + Active/Passive Loudspeaker.
     
    Following @pinnahertz's request can you tell how is powered each element in your chain:
    - battery or AC/DC converter ?
     
    Edited: typo
     
  7. Indigo Bob
     
    The macbook Air is powered with a three prong chord typical of mac's.  Nothing special.
    MAC +(USB)+  FIIOX3II+ EARPHONE= USB NOISE
    or
    MAC +(USB) +  HVA + EARPHONE= USB NOISE
     
    X3II + (HVA) +EARPHONE= NO NOISE.
     
  8. Indigo Bob

    YAH, it's a gamble.  Some reviews have said that it clears the background noise up well so I thought I'd give it a try since I can return it with no charge.
     
  9. WindowsX
    1. remove laptop adapter
    2. use shielded usb cable
     
  10. pinnahertz
    1. Yes, try it with the Mac on battery power
     
    2. No, that won't help at all.  Don't bother
     
  11. WindowsX
     
    From my own experience setting up home studio, some problems with buzz and hum from usb audio connection can be solved by using shield cable. I didn't tell him to buy expensive cable, just get better ones with follow design specifications properly.
     
  12. Arpiben
    Thanks. Would you mind telling how is powered X3II and HVA ? Batterry or electrical charger/plug?
    Basically the goal is to verify if noise is still present when everything is battery powered.
    If not, put everything on battery ( MAC included as per @pinnahertz post) and tell us.
     
  13. pinnahertz
    His problem is most likely ground loop. A heavily shielded USB cable might tend to force the computer and DAC grounds together but that's the wrong way to do it, as the ground current is carried in the shield. You want the devices at the same ground potential with as little current as possible in any interconnect. Using a shielded USB cable doesn't fix the problem, it only puts a band-aid on it (hides it from plain sight).
     
  14. WindowsX
     
    Wrong way to do it? Maybe you should read cable assembly document from USB.org
     
    http://www.usb.org/developers/docs/whitepapers/USB_SuperSpeed_CabCon_Whitepaper.pdf
     
    For most of the times, many vendors recommend to build cable with shielding connected between device. Well, using shielded USB cable fixed these kinds of problems for me. Well, it's up to author whether he want to invest $5-10 on shielded USB cable first or try to find ground loop issues in that place (if any).
     
  15. Indigo Bob

    I wouldn't mind trying a shielded usb cable.   It's a fairly affordable option.  I didn't even know these existed.
     
    Do you have any suggestions of where to purchase them from in the US.  I am unfamiliar with them and amazon doesn't seem to have a large supply.
     
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