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Thread: Where do I got from here?

  1. #1
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    Where do I go from here?

    I have various type of noise in my system and I am not sure what to do about it and need some advice. My components:

    Alpine 7897 Headunit
    Soundstream DaArtagnan 5.1
    MB Quart highs
    Infinity Kappa perfect 12.1D


    Micro-Atx computer
    1.2GHz Tbird
    Radeon VE
    Soundblaster Live

    300W invertor.


    Ok. I have the headunit and my composite LCD screen up front. Computer, amp, and sub in the trunk. I have all signal wires running on the driver's side of the car. All power wires on the passenger side.

    RCAs run from the HU to amp.
    Another set of RCAs run from the computer to HU and LCD.

    Remote wire runs to 30A SPDT Relay. Relay sends 12V+ to remote on amp and anther 30A SPDT relay to power on inverter.

    Grounds:
    Motherboard tray, Power Supply, Invertor - In, Invertor - Out, Relay -, all run to a distro block which is the grounded to the same spot as the amp. (The rear seat bolt)


    I am still waiting for my alpine RCA adapter so I have no sound hooked up to the computer yet.



    The problems are:

    1 - Humming comming from the highs when headunit powers on. Stays pretty constant. Not horribly loud but noticeable on pause.

    2- Alternator noise. Noticeable on pause.

    3- Horizontal lines scolling up through video screen. Noticeable all the time.


    I really want to figure out how fix this correctly. I would like to avoid using filters. I've done searches and I would like to know more about removing caps from the PSU. Does this work really well? Also is there any way that I can better ground everything? I am just kinda clueless of where to go next and need some direction. Thanks.

  2. #2
    Maximum Bitrate carabuser's Avatar
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    is the hu grounded? make sure no power cables cross with signal wires. I had a similar problem in my old car. The reason was - the remote cable from the HU ran along with my signal wires. but I assume it's not that in your case.
    try disconnectin one device at a time (completely) and see which one causes the problem.
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  3. #3
    Constant Bitrate blicky_1's Avatar
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    Quote Originally Posted by 1BlackHatch
    I have various type of noise in my system and I am not sure what to do about it and need some advice. My components:

    Alpine 7897 Headunit
    Soundstream DaArtagnan 5.1
    MB Quart highs
    Infinity Kappa perfect 12.1D


    Micro-Atx computer
    1.2GHz Tbird
    Radeon VE
    Soundblaster Live

    300W invertor.


    Ok. I have the headunit and my composite LCD screen up front. Computer, amp, and sub in the trunk. I have all signal wires running on the driver's side of the car. All power wires on the passenger side.

    RCAs run from the HU to amp.
    Another set of RCAs run from the computer to HU and LCD.

    Remote wire runs to 30A SPDT Relay. Relay sends 12V+ to remote on amp and anther 30A SPDT relay to power on inverter.

    Grounds:
    Motherboard tray, Power Supply, Invertor - In, Invertor - Out, Relay -, all run to a distro block which is the grounded to the same spot as the amp. (The rear seat bolt)


    I am still waiting for my alpine RCA adapter so I have no sound hooked up to the computer yet.



    The problems are:

    1 - Humming comming from the highs when headunit powers on. Stays pretty constant. Not horribly loud but noticeable on pause.

    2- Alternator noise. Noticeable on pause.

    3- Horizontal lines scolling up through video screen. Noticeable all the time.


    I really want to figure out how fix this correctly. I would like to avoid using filters. I've done searches and I would like to know more about removing caps from the PSU. Does this work really well? Also is there any way that I can better ground everything? I am just kinda clueless of where to go next and need some direction. Thanks.
    Is the alternator suppressor ok?? some can be replaced some are built in, i had a simular problem with HU and amps.

  4. #4
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    The signal wire are all on one side of the car, and the power wires are all on the other. This hum is there as soon as the inverter kicks on. The hum was never there before I put the computer in. The stereo never made this sound before. I am going to go play around with my gounds and see what I can find out.

  5. #5
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    Ok. I just did some more testing. Whenever the PSU isn't plugged into the invertor the noise is barely noticeable. Whenever the PSU is plugged in it returns. Any ideas?

  6. #6
    It ain't easy being a green moderator meddler's Avatar
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    Quote Originally Posted by 1BlackHatch
    Ok. I just did some more testing. Whenever the PSU isn't plugged into the invertor the noise is barely noticeable. Whenever the PSU is plugged in it returns. Any ideas?
    Sounds like the inverter. Inverters aren't exactly the cleanest power source. Maybe look at cleaning your earth points, mounting the inverter on a piece of wood (sometimes you can get an earth loop through the case. It happens quite a lot with amps) or grounding at a single point for all of you equipment. You could also try larger earth wires. Sometimes you get a high resistance through the wire.
    Never let the truth get in the way of a good story

  7. #7
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    Quote Originally Posted by meddler
    Sounds like the inverter. Inverters aren't exactly the cleanest power source. Maybe look at cleaning your earth points, mounting the inverter on a piece of wood (sometimes you can get an earth loop through the case. It happens quite a lot with amps) or grounding at a single point for all of you equipment. You could also try larger earth wires. Sometimes you get a high resistance through the wire.
    The inverter is mounted to a piece of MDF. All ground wires to the distro block are 10AWG then from the block 4AWG to chasis. Everything computer oriented runs to that block.

    I just tryed a different inverter. The noise was actually worse. I figured with a smaller inverter it'd be somewhat better. Guess not.

    My next step is to remove the filters from the PSU. I am gonna have my friend the electronics guru do that.

    Any other ideas in the meantime?

  8. #8
    I'm sorry, and you are....? frodobaggins's Avatar
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    Quote Originally Posted by 1BlackHatch
    Any other ideas in the meantime?
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  9. #9
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    Ok. I don't think I have a ground loop since I tried grouding the head unit in the back where I ground my amp and CPU. Still the same hum. I guess I will hafta do the PSU hack.

    Can anyone explain what is going on? Some sort of feedback on the DC power source or ground? Will a Cap or any type of filter help this from being transmitted to the amp?

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