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Thread: Noise with only DC-DC + Swix to factory headunit

  1. #1
    Low Bitrate uptpilot's Avatar
    Join Date
    Jun 2005
    Oklahoma City

    Noise with only DC-DC + Swix to factory headunit

    I just installed a carputer into my 2000 Honda Civic EX. Here's the configuration:

    Factory Headunit <--> PIE <--> Line in from TurtleBeach Systems Amigo USB soundcard (very clean sound) <--> Aspire Aspire One Netbook <--> DC-DC cigarette lighter power supply adaptor for netbook.

    PIE =

    The sound comes up very noisy with all kinds of static and especially a dirty tone that is coincident with the RPM's of the alternator. The noise is like a whine/tone/whistle laced in with static. The TBS Amigo soundcard is VERY clean except for in this car. I've muted Mic In and Line In (although I want to use Mic In for XM). I'm using a PIE to prevent the noise I'm getting. I used a PIE in a Mazda 6 and it works beautifully. In addition, when I used an AC inverter to power the netbook using its own PSU, it was even noisier. I figured that purchasing the netbook's OEM DC-DC cigarette lighter adapter would also help but it hasn't. Any ideas?


  2. #2
    MySQL Error soundman98's Avatar
    Join Date
    Jan 2008
    on the border of northern IL/IN
    what is a PIE? (it's making me hungry ) i am assuming that it is another name for a aux adapter...

    sounds like you have a ground loop problem...

    sometimes ground loop isolators(you might also see them reffered to as GLI's) work, sometimes they don't, but even when they do work, they are only covering up a problem, and not correcting it...

    i would recommend trying to hard wire the adapter to the car. it is very possible that the cigarette lighter in your car is in a separate circuit/ground than the radio, is poorly grounded, and/or has poor/weak power--and all or any of those can cause the issues your describing.

    the easiest way to test this is to run wires outside the car for power and ground for the adapter, and try powering the computer from those.

    another idea for power is to try to tie into the power and ground connections for the factory radio-- so that your carputer and stereo use the exact same power source.

    then, a last idea if none of the above seems to quiet it down, try grounding the sheild of the rca's connecting the carputer to the stereo-- sometimes a odd voltage difference between equipment will also cause a hum.

    ground loops are one of the many annoying little gremlins that will cause grey hair, stress disorders, loss of hair, or appetite...

    good luck, i am sure others will be able to chime in later with some other solutions incase the onese that worked for me that i listed don't work.

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