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  • NOISE! help please.

    I got my inverter today and hooked it up, anything I connect to it creates static or a buzz in all the speakers! I thought maybe its because the speaker wire is next to the power wire but then I disconnected the rear speakers and it still came in from the front speakers. The computer is not even turned on, I just plug it in and it starts the noise, should this happen, could it be beacuase I am running the power cordes right through my dash because I have a relay there?
    http://www.detz.net/detzbmw.jpg

  • #2
    Is it while the car is running? If you press on the gas does the noise change? If so it is alternator noise, and you don't have everything grounded right. Search the forum it has been covered many times.
    http://www.mp3car.com/usersites/Maveric/ M.A.V.I.C. System
    Asus MB, PII 266, 192 MB Ram, 6.8" LCD, 6 Disk CD-ROM, 21 Gig HD, All-in-Wonder Video w/ TV Tuner, Irman, Windows ME, Winamp, Cobra III -- All in a custom acrylic case.

    http://www.mp3car.com/usersites/listings/ MP3car Listings - Please add to it! :)

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    • #3
      no the car is not running. I just read through like 20 threads about this and I came up with some questions. When it says to ground the computer to the same spot as the inverter, do they mean the case or the actually computer(if computer how do you do that).
      http://www.detz.net/detzbmw.jpg

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      • #4
        I tried hooking the inverter directly to the battery, like a foot away and then trying it with the car off and it still gave a buzz...how should I ground everything, should I tape wires to the case and the psu and ground those to the same place as the inverter?
        http://www.detz.net/detzbmw.jpg

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        • #5
          I found this in my readings...

          1- ground your computer PSU case to same ground as your inverter. This SHOULD take care of MOST of the noise but not all...at least not in my attempts.
          Do I just tape the ground on there or is there somewhere on the psu that was a ground?

          2- If you have a separate amplifier connected to your speakers, try having all of them grounded together to a distribution block. The same goes to the power cables too...

          3- Ground your computer PSU to the head unit ground or the amplifier ground whatever is connected to the speakers

          About #3... With my setup where everything is powered up from same source except for the head unit, this ONE ground cable( using aligator clip) got rid of ALL the noise...and i mean ALL OF IT...zero...

          Does this all make sense...I can't seem to get rid of the noise and the computer is not even on, neither is the car...
          http://www.detz.net/detzbmw.jpg

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          • #6
            If the car is not on, and the computer is not on, then you should have no noise at all! I am assuming you have the key on the aux position. Are you sure it is not just volume noise? Give a more detailed description of your setup. Do you have a amp, how is it connected to your headunit, how are you getting the sound to the speakers (FM modulator... tape adapter... aux connection?).

            When we talk about grounding the PSU, we mean you should screw a ground wire to the chassis, just sand the paint off of a hidden spot then drill a guide hole for a screw then connect the wire from the PSU to the screw. As for the grounding point on the PSU itself, just connect the wire to one of the screws that are holding the outside case of the PSU together. Or if you are using an actual PC case you can connect it to the frame.

            Another option is to get a ground loop isolator, but we need to figure out the problem first.
            http://www.mp3car.com/usersites/Maveric/ M.A.V.I.C. System
            Asus MB, PII 266, 192 MB Ram, 6.8" LCD, 6 Disk CD-ROM, 21 Gig HD, All-in-Wonder Video w/ TV Tuner, Irman, Windows ME, Winamp, Cobra III -- All in a custom acrylic case.

            http://www.mp3car.com/usersites/listings/ MP3car Listings - Please add to it! :)

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            • #7
              ok...I have the power coming from the battery to a realy to a switch...then it goes to the trunk to the inverter. THe audio comes out from the computer and down cables(on the other side than the power) and connects to an aux on my head unit. The car is not on, the computer is not on, but I have the key turned so I can play the stereo. And only when the inverter is on is when I get the buzz. I connected everything from the outlet in my house and it worked perfect, but once I introduced the inverter problems started.
              http://www.detz.net/detzbmw.jpg

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              • #8
                I've been hearing mixed things about the ground loop isolators, some people say they work, some say they don't, others say it makes it worse or the sound quality drop. I would to see how much noise I can get rid of before I try one of those.
                http://www.detz.net/detzbmw.jpg

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                • #9
                  try ground first. Take the negitive wire out of your inverter and find a place to screw it into your metal body on your car. Make sure there is no paint. To screw it in.. you can pick up the hookups at radio shack or any car part store. They have little circles on the end and allow you to attach the wire too. Make sure you get one to fit the guage of your wire. Then make on for your computer and find a screw that screws into your PSU and ground it to the same point as you grounded your inverter.

                  I don't know where you ran the neg off your inverter but don't go back to the battery.. just ground it to car body.
                  '98 Explorer Sport
                  http://mp3car.zcentric.com (down atm)
                  AMD 800mhz 192megs RAM 60gig hard drive 9 inch widescreen VGA
                  80% done

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                  • #10
                    Yeah, I have alternator and HD noise, they said it was a ground loop, I got rid of the ground loop, but still have noise, I grounded the case to the same spot as the powersupply (through the same cable, and socket) still noise.... why???? Okay, I know my cable isn't shielded, but how come I get HD noise??? (okay, I'll get a shielded audio cable..) :P it would seem that the noise is comming through the soundcard, is this possible??????????? probably, I think I will get a shielded cable.. lol!!! actually, I already have a cable run that is shielded, but I have to put plugs on teh end....
                    2 week temp ban (spam and complaining about deleted posts)
                    register another account and you're gone for good.

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                    • #11
                      You cant get rid of all the noise, especially the hard drive. Even on my desktop machine with headphones plugged directly into the back of it there is some hard drive noise present during accessing. The electronics arnt shielded enough to cut out all the EMF.
                      -------------------------------------------
                      (=========-) 99% complete
                      --------------------------------------------
                      AMD K6/2 500 @ 450mhz to keep heat and power usage down, 64Mb, slim CDrom drive, 64mb USB pendrive for MP3 transfer, 10Gb 2.5" drive for MP3, USB>RS232
                      All jammed in external CDROM drive case.
                      Kenwood KVC-1000r In-Dash LCD. x-10 MouseRemote. Destinator V2 Gps. DC-DC with onboard Shutdown controller.
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                      • #12
                        I grounded the invert to a screw in my trunk and I have a ground wire coming from my computer as well but there is still a lot of buzz...the weird part is the computer is not even on yet and it still does it. Someone mentioned to ground everything to the same place the head unit is grounded, but doesn't the head unit groud to the battery?
                        http://www.detz.net/detzbmw.jpg

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                        • #13
                          Really the whole car chassis is the ground. That is why when you jump a car battery you attach the positive to the battery and the negitive to the chassis. Have you tried it with the whole system running (car+computer)? Does it have noise then?
                          http://www.mp3car.com/usersites/Maveric/ M.A.V.I.C. System
                          Asus MB, PII 266, 192 MB Ram, 6.8" LCD, 6 Disk CD-ROM, 21 Gig HD, All-in-Wonder Video w/ TV Tuner, Irman, Windows ME, Winamp, Cobra III -- All in a custom acrylic case.

                          http://www.mp3car.com/usersites/listings/ MP3car Listings - Please add to it! :)

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                          • #14
                            from what I know about ground loop isolators they will filter the noise problems of having too many different grounds. If you have grounds all over the place it might clean up the problem.

                            So this noise comes when you just turn the electricity on? the car is NOT started right?

                            What kind of sound card are you using also? I have heard that some onboard sound cards are crappy and produce a lot of noise if you use that. I have a soundblaster Live and have no noise.. The only noise I ever got was when i found out my rca cables were picking up noise coming from either the metal or carpet.. i just put some tape around the connectors and it took it away.
                            '98 Explorer Sport
                            http://mp3car.zcentric.com (down atm)
                            AMD 800mhz 192megs RAM 60gig hard drive 9 inch widescreen VGA
                            80% done

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                            • #15
                              well right now I am just testing it out with my computer so its a SB live but when I finish the computer that is going in the car its going to be a SB PCI128.
                              http://www.detz.net/detzbmw.jpg

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