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    New AC adapter creates noise through headphones

    Discussion in 'Sager and Clevo' started by AlfaWolf, Jun 13, 2009.

  1. AlfaWolf

    AlfaWolf Newbie

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    I recently bought a new universal AC adapter for my Sager NP5720 to replace my old, fraying one. Its output is marked at the same amps as the old one (6A) and I adjusted the voltage on it to match the old one (20V). When it plugs into my laptop though, I hear a high pitched fuzzy noise coming though my headphones.

    My headphones are connected through a cheap USB sound card, and when I switch them to the built-in Realtek sound card, the noise goes away, but then I have to deal with the reduced sound quality of the card. Interestingly, when I am physically touching the laptop (or even just a couple inches away from physical contact), the noise becomes dramatically reduced.

    Should I find a new adapter? I ordered this one online and would like to avoid the hassle of returning it if possible.
     
    AlfaWolf, Jun 13, 2009
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  2. Cookie

    Cookie Notebook Evangelist

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    You say that when you touch the laptop the noise goes away. I assume you're touching a metal part of it? Does your new AC adapter have proper grounding? And more important, does your house have a proper grounding system?
     
    Cookie, Jun 13, 2009
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  3. AlfaWolf

    AlfaWolf Newbie

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    AFAIK, the power strip and the house itself are both properly grounded. I tried plugging the adapter into another strip plugged into another power outlet, but the problem persisted. This issue did not exist with the old AC adapter, so am I correct in assuming that the problem would not be in the grounding?

    EDIT: Almost forgot, it goes away when I am touching or close to touching anywhere on the laptop, such as the keyboard, which is plastic.
     
    AlfaWolf, Jun 13, 2009
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  4. Cookie

    Cookie Notebook Evangelist

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    So when you're touching even the plastic it goes away? That is indeed strange. What if you run the laptop on battery? Does the problem go away then?

    If it does, I'd recommend you to use an outlet which is NOT grounded. I also have noise issues, and I eliminated the problem by using a non-grounded outlet.
     
    Cookie, Jun 13, 2009
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  5. AlfaWolf

    AlfaWolf Newbie

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    After some experimentation:

    It makes no noise on battery power
    It makes noise if plugged into a power strip or directly into the wall
    The sound is reduced while touching plastic, but it is more significantly reduced when touching metal.
     
    AlfaWolf, Jun 13, 2009
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