Shock from 2010 MBP and guitar.

Discussion in 'MacBook Pro' started by conanthewarrior, Nov 5, 2014.

  1. conanthewarrior, Nov 5, 2014
    Last edited: Nov 5, 2014

    conanthewarrior macrumors member

    Nov 5, 2014
    Hi everyone, I have a strange problem.

    My MBP is fine when used alone, but If I am reading tabs online and playing my electric guitar, if I touch the case of the mac, and my guitar strings, I get a shock.

    It is not a big shock, but it is enough to know it is there, and if I keep my hand on it it is constant, not a sharp quick jolt, but continuos.

    As you can guess, this gets quite annoying when I am trying to learn a song constantly having a tingle go through my arms.

    Any ideas what I can do? I've also posted on a guitar forum, and got some help there, and it appears that my guitar is correctly wired.

    Any help would be much appreciated, Conan.

    EDIT: I just saw another thread that reminded me of something, I am using a non apple magsafe charger, if that makes a difference.
  2. uller6 macrumors regular


    May 14, 2010
    Sounds like a ground loop problem: your ground level voltage on the guitar strings (grounded) is different from the ground level voltage on the case of your MBP (also grounded). The same thing used to happen to me on my old powerbook when I played. In my case, the issue was a broken ground pin on my amp's power cord.

    Make sure you're using the 3 prong grounded extension cord on your power adaptor - if you use the 2 prong connector your laptop won't be correctly grounded and you may have this issue. Also try plugging the laptop into the same power strip as the amp (in case you have ground level shifts between different outlets in your house). Or, as you say the issue could just be that you're using an off-brand power adaptor.

    Good luck!
  3. conanthewarrior thread starter macrumors member

    Nov 5, 2014

    Im in the UK, so all plugs are 3 pronged. The ground prong on the third party adapter is plastic though, so I guess it doesn't work.

    Is this dangerous? If it is I guess I will have to get a different power adapter.
  4. Fishrrman macrumors G5


    Feb 20, 2009
    [[ Is this dangerous? ]]

    It could be VERY dangerous, if there's a problem with the house wiring.

    At the very least, get a power strip, preferably with a grounded plug, and plug both the computer AND the guitar amp into the SAME power strip.
  5. snaky69 macrumors 603

    Mar 14, 2008
    The third prong being plastic means your MBP isn't grounded at all. I'm always weary of using non-grounded AC adapters for expensive electronic equipement, but that's just me.

    Perhaps you could borrow a genuine AC adapter from a friend and see if the problem goes away?
  6. conanthewarrior thread starter macrumors member

    Nov 5, 2014
    To be honest everyone else I know uses PC's, so I unfortunately can't borrow a charger. The power strip sounds like a good idea, as I think our house wiring could be bad, lightbulbs always explode and the powers always tripping.

    Should I get a standard one, or one of the more expensive ones with say a surge protector or something?
  7. jerirat macrumors newbie

    Jul 30, 2013
    Get a power strip with a surge protection!! And please get your house wiring fixed. Exploding lightbulbs is not good.

    I'm getting ready to install a whole house surge protecter but I will still use individual surge protecters on all my computers and home entertainment equipment.
  8. BigBuns macrumors newbie


    Oct 24, 2014
    North America, eh
    Yikes... Sounds like the grounding problem from your third party apple adapter is the least of your electrical worries.

    And yes I would also recommend getting a surge protector to connect both plugs into so they are grounded together... and then maybe get an electrician to check into those exploding lightbulbs :confused:
  9. burgman macrumors 68000


    Sep 24, 2013
    Google about musicians and electrocution then decide if an Internet forum is your best plan to save your life.

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