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ground loop isolator help

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  • ground loop isolator help

    BACKGROUND:Well i was going to make my own power supply, but i got lazy, and will probably hold off with that for a little. right now im using an inverter. it works just fine. but the noise is evil! Its not the inverter... its the ground... ive figured this out by touching the ground of the computer plug (with no inverter) to the ground of the car (while computer is off) and the noise goes straight through the sound card into my head unit!! ahh.. seems to be the alternator since the majority of the noise is matches my Tachometer, but i can hear just about everything go on and off in my car....

    I bought a power noise filter (the Scorsche sold on this site). hooked the one end (input) to the + of my battery, and on the other side (output) there is the + and - that is hooked to my inverter (i still dont get how you can make a ground from just the + from the battery). Well, The inverter powers up just fine. The problem is when the computer goes on the inverter starts going through a loop of sending power to the computer, then cutting it with the "power low" alarm. The filter is rated at 10 amps... and the inverter can push out up to 1.75 amps...
    any help?
    Digital Chaos

  • #2
    If you got a Radio Shack near by get a audio system groud loop isolator Cat. No. 270-054

    I use it and it killed the different humming sounds comming from my sound card.(oh it goes inline with your sound card's output.)

    Hope that works for ya

    [This message has been edited by JrFaust (edited 03-05-2001).]
    That's right, you just got passed by a computerized toaster...


    • #3
      Yup, that worked for me too. Much easier than the other options.
      Car: 1999 Dark Green Mustang GT Coupe
      Audio: Alpine HU, JL 6ch Amp, JL Stealthbox and XR series components.
      Player: Empeg for now; something custom later. - Custom built laptops!


      • #4
        hmm, well before i had posted this i picked up another noise filter, but from radio shack.. it has a + and - input; + and - output. basically the same thing as the scorche.
        Here is the comparison of the 2 being hooked up between the inverter and battery:
        scorche: got rid of ground noise from the car, and ground noise from the inverter. But when i turned the computer on... the inverter would go into that damn loop.
        Radio Shack: I could power everything up this time, but it did absolutely nothing.

        My goal was to kill the sound before it hit the sound card. But now that i think of it, you guys are right. i'll be off to radioshack soon too pick up the isolator that goes into the audio lines.. hope it does the trick, thanks again... ill post my results soon.


        • #5
          I had the same experiences with the radioshack 12v filter -it did nothing.

          I bought the audio filter, and it works great.
          Techonlogy on Wheels


          • #6
            well.... the filter worked 100% !!!!
            thanks guys


            • #7
              GLI ( Ground Loop Isolator) is the solution for everything!!. Forget the +12V filters... this baby took care of all the noise i had from alternator and inverter.
              04 Acura TL w/ core2duo 2ghz laptop w/ 1gb RAM on a docking station.

              Fast car, fast PC. ;)


              My TL CarPC ver2

              FSR Flash Skin w/ moving weather maps


              • #8
                yeah ground loop got rid of nearly all my noise but sub amp still humms.. piece of **** amp.. next amp i get will have low pass filter.. should sort it..

                GLi's do rock yea, little ugly though =[
                John McLear - [email protected]
                UK Mp3car slapnut
                #mp3car - Efnet
                Carplayer and Mediaengine *****
                spank for holding my motherboard for so long. still no board, wood work nearly done :|
                [-----------(90%)----] Completed :)
                pics at:


                • #9
                  I still have some noise from the inverter (i think) but the last time I tried a GLI it got rid of the noise but it sounded like the music was being played in a big hall a long ways off. Any clue why it doesn't work for me???


                  • #10
                    mp3wrangler, the GLI is a pair of coils I believe and if it's close to a power source you might be getting EMI signals.

                    Just a thought,
                    That's right, you just got passed by a computerized toaster...


                    • #11
                      I tried a ground loop isolator for Radio Shack and it made more noise than it filtered. Any ideas why?
                      Jeff Rapp
                      [email protected]
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                      achievaMP3 - The Digital Oldsmobile</A>