Unusual buzzing sound to headphones/speakers when ethernet connected

Discussion in 'MacBook Pro' started by xtremesniper, Feb 2, 2014.

  1. xtremesniper macrumors newbie

    Joined:
    Dec 12, 2011
    #1
    Before I say anything: This is not like the other threads about this issue because my issue happens even without the power adapter plugged into my laptop.

    I have a 2010 15" MBP that I have been using with my exact same setup for years with no problems.

    Yesterday morning I woke up and the only thing I did differently was swap out my RAM to my new replacement RAM that just came back from RMA.

    After that, (and after a lot of troubleshooting to narrow it down), it seems that any time I have my external speakers or headphones plugged in and I have my ethernet cable connected, I'm getting a lot of buzzing noises.

    It seems to also happen when I connect my external monitor but it's much more amplified with the ethernet.

    Get this: I went to my router and took a roll of wrapped ethernet, plugged one end into the router and I merely touched the roll of ethernet up against the metal casing of the MBP and the buzzing could be heard through the headphones. Plugging the ethernet cord in just made it that much louder.

    I'm pretty convinced this has something to do with a lack of shielding in the MBP. I don't know why it became more evident now than it ever was before. Swapping the RAM back did not solve the probem. I'm not sure if I could have done something to mess with the shielding but I've opened my casing tons of times before with no adverse effects.

    Does anyone have any ideas?
     
  2. w00t951 macrumors 68000

    w00t951

    Joined:
    Jan 6, 2009
    Location:
    Pittsburgh, PA
    #2
    It's a fairly textbook case of EMI (electromagnetic interference). This is why audiophiles and professionals have separate audio interfaces that reside away from the "noisy" internals of a computer.

    Really nothing you can do, aside from using WiFi/purchasing an external DAC.

    And there a lots of tiny brass pins that are supposed to contact the back case and act as a ground - you possibly did not seat the cover properly, exaggerating the effects of EMI.
     
  3. xtremesniper thread starter macrumors newbie

    Joined:
    Dec 12, 2011
    #3
    Indeed, I noticed those pins immediately and dusted them off and made sure all of them were still springy (so they make the connection to the back plate).

    I don't think the case is sitting any differently than before, but it's possible that those pins are somehow the cause of the problem anyway. It's a shame because it's never been a problem until now, and the fact that it only happens when ethernet is connected is just puzzling.

    I didn't think about using an external DAC, so thanks for the idea.

    I'm guessing taking the MBP to the Apple Store would be fruitless?
     
  4. w00t951 macrumors 68000

    w00t951

    Joined:
    Jan 6, 2009
    Location:
    Pittsburgh, PA
    #4
    I mean, if the problem was intensified for certain by removing the case, then by all means go. But a slight buzzing or hissing through the onboard audio jack is completely within spec.
     

Share This Page