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  • perfect sound with an invertor

    Im just wondered how people have managed to get perfect sounds when using an invertor, getting rid of noise.

    I know earthing the Power supply can do it
    So can using a ground loop isolator and a low pass filter / active crossover..

    Any other ways?

    jose http://oacar.mp3car.com http://faq.mp3car.com
    John McLear - [email protected]
    http://www.205oc.co.uk
    UK Mp3car slapnut
    #mp3car - Efnet
    Carplayer and Mediaengine *****
    spank gemma.co.uk for holding my motherboard for so long. still no board, wood work nearly done :|
    [-----------(90%)----] Completed :)
    pics at: http://www.zcentric.com/~mitcht/gall...me=Convertable

  • #2
    I have an inverter and also clear audio!

    I just grounded everything and the noise was gone.
    www.arbybean.com

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    • #3
      GROUND LOOP ISOLATOR

      Get one now.

      I've NEVER heard an inverter noise after running one of these in the line. Power line filters are crap too. Get a GLI.
      Public PGP key available on http://keyserver.pgp.com/pks/lookup?...@MyRealBox.com

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      • #4
        I think im one of the few people that used an inverter (and always have) and have never had a problem with noise with it. Its a statpower ProWattz 150watt inverter, and it works great.. NEVER have had any noise.. It was a bit more expensive but it works perfectly.

        Now, I used a Statpower PortaWattz 1400watt inverter for a bit in the middle and it buzzed like hell until I grounded it.. but it was a much cheaper inverter.. The quality really matters.

        Of course I would prefer to move to a DC-DC supply at some point, but the inverter does work perfectly well if you don't want to go that route.
        MP3 Cavalier - http://www.mp3cavalier.com
        MP3 Grand Prix - http://www.mp3gp.com

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        • #5
          when i was testing saturday i had absolutely no inverter noise, over a pair of headphones.

          i Haven't had a chance to check it out with the tape adapter

          only time will tell

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          • #6
            headphones won't do it, as you don't have a ground loop using headphones.. the grounloop is created when the computer and the radio are connected.

            anyway. I have GLI and it helps, but the PSU or Case has to be grounded (i use the same cround point as the inverter and amp) for it to be crystal clear. Plus my sound card has a Signal to Noise of 90 dB... that helps.
            I cheat, I own an empeg.
            Meskimen's Law: There's never time to do it right, but there's always time to do it over.
            http://civic.mp3car.com

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            • #7
              okey let me rephrase
              If you guys are using tape adapters and the like you wont hardly notice it.

              My Sound goes straight into my amps

              --<=
              jack - 2x rca
              then it goes to gli

              its when i have both amps plugged in i get an buzzing

              if one of em is plugged in its fine.

              And if the jack aint in the PC again its fine, weird eh

              John McLear - [email protected]
              http://www.205oc.co.uk
              UK Mp3car slapnut
              #mp3car - Efnet
              Carplayer and Mediaengine *****
              spank gemma.co.uk for holding my motherboard for so long. still no board, wood work nearly done :|
              [-----------(90%)----] Completed :)
              pics at: http://www.zcentric.com/~mitcht/gall...me=Convertable

              Comment


              • #8
                I use an inverter and a tape adaptor, I have no inverter noise, when the computer is on, but when the computer is off, I get a ticking sound that is from my engine (i.e. I give more gas faster ticking)
                --BLK
                Wide awake
                and keeping distance from my soul - Tool

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                • #9
                  I use an inverter and a tape adaptor, I have no inverter noise, when the computer is on, but when the computer is off, I get a ticking sound that is from my engine (i.e. I give more gas faster ticking)
                  I had the same problem with tape adapters. Only I had a high pitched noise and it got higher with the amount of RPMs. The only thing I could figure is that when the engine's RPMs increase so does the alternators output (ie.. step on the gas and more power is generated), and that power is going to the source of your music, (computer, cd player w/cig lighter plug, etc..) and then into your stereo. That noise totally stopped when I got a FM modulator. I highly recommend using one if you dont have audio inputs for your stereo. (BTW I am using it for a portable CD player right now)

                  As for inverter noise I don't have my computer installed nor do I have an inverter yet. But I have planned the whole grounding situation out. When I built the computer case (check it out and tell me what you think) I added a bannana plug input and wired the hard drive, motherboard, and power supply to it. So when I go to install I just have to plug in the bannana plug that has been grounded to the cars body. And since the inverters ground will be attached to the body I shouldn't have a problem. If I do then GLI all the way!

                  BTW Jose I just noticed our member numbers 1339 and 1338. Cool
                  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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                  • #10
                    A guy by the name of BJ talks about removing the "phase correction capacitors" from a standard 110/220 PSU to remove noise, his website is at http://home.primus.com.au/bravo/
                    this info is on his "Projects" page under the link "BJBlaster car MP3 Player" then the "Power Supply" link. Have not tried this yet, but it seem's reasonable.

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                    • #11
                      I'm using a Tripplite 140W inverter and have perfect sound. The audio output from the computer goes directly to an amplifier.

                      I didn't do anything but ground all the devices well.
                      Player: Celeron II 633MHz, 256MB RAM, 20GB IBM 9mm 2.5" Laptop HD (180G/2ms), onboard ethernet/sound/video/tvout, 10"11"x3" case, MPBS1 70W DC-DC PS w/auto-shutdown controller, in-dash lighted switches, 7" NTSC TFT widescreen in-dash LCD, touchscreen, rear-window brake light installed Garmin GPS35 GPS, credit card sized IR remote w/IRMan, mini-wireless keyboard/mouse (sits under seat), PowerMate black knob, MP3s and GPS Navigation (Winamp, CoPilot, SA8.0).
                      Car: 1993 Nissan Maxima, Black Emerald

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                      • #12
                        another thing to note, if you use a high quality car amplifier, it will have isolated inputs already, meaning it has a line isolation unit built into it.(well it acts like one anyway) It does this with the type of "floating power supply" that these amps use to get high voltage and current. My Alpine amp runs @ 35V+/- at 3.5A per rail. But because of the switchmode design, the earth point floats.

                        This basically means, if your amp is a goody, then you won't have any problems running the sound card directly into the amp. A quick test you can do to see if your amp is isolated, touch the rca input terminal (outside ring) with your finger, if it hums/buzzes, then you know that the RCA earth is floating.

                        The rule of thumb is to keep one end of your rca cable earthed only. So if it is earthed at the computer, then you want the other end to be floating. A good amp does this for you, but you can do this by using a Line Isolation Unit, or disconnecting the sheild from the rca cable on the amp end.

                        Just something to add....
                        BjBlaster! Car MP3 & Carputer!
                        bjblaster.com

                        "The solution to one problem is only the beginning of another"

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                        • #13
                          Ok, this is very interesting, but I'm not sure I totally get it.

                          I'll use my problem as an example. I have a pretty decent 4 channel Sony amp for my primary speakers (no sound problems there) and a cheap 2 channel amplifier for my subwoofer (because I'm broke right now). Obviously, I would expect _some_ problems with the cheap amplifier, but the engine buzz in the subwoofer is VERY LOUD. Oddly, if I connect a Ground Loop Isolator in line with the sub amp, it silences EVERYTHING. No sound at all.

                          The audio signal comes out of the computer sound card, and into an EQ. The EQ splits it into front/rear and sub outputs. It's passive, so it's quite unlikely to be throwing any noise in itself.

                          I haven't been able to find a good place to ground the sub amp that will make it quiet.

                          How can I use this information about RCA grounding to see if it's the cause of my problem?

                          -Matt
                          Public PGP key available on http://keyserver.pgp.com/pks/lookup?...@MyRealBox.com

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                          • #14
                            try running your sub amp directly from the sound card to see if it has noise...if so, your passive crossover isn't balanced properly, thus causing noise from your amp. I suspect it's a bit strange, as you said your GLI cancels all audio when plugged in.

                            Also try putting the GLI straight after the S/Card.
                            BjBlaster! Car MP3 & Carputer!
                            bjblaster.com

                            "The solution to one problem is only the beginning of another"

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                            • #15
                              Could anyone tell me why I would be getting very fuzzy output from a portable dvd player, when its powered by a DC adapter and sound is input to the stereo through a tape adapter? It sounds fine when the player is powered by its batteries, but fuzzy when hooked up to the DC adapter....

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