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Thread: Static Interference help please?

  1. #1
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    Static Interference help please?

    Hi,

    Can somebody please help me?

    I have installed a 600W mcfun amp behind my dash as described here

    http://cgi.ebay.nl/600W-ENDSTUFE-CAR...-/330426887015

    Due to static interferance (engine revs & general buzzing) I have disconnected everything to start again. I have now just connected the amp & earthed the amp directly to the scraped bare metal chassis of the car (MK6 Golf) & connected the speakers only to get horrific static all the time (even worse when I connect the power supply to the laptop when all connected!!) the only way I can reduce it to an acceptable level is to use ground loop isolators but I can still hear it (also reduced by 90%) I have tried earthing the amp to the cars wiring loom but with exactly the same results... can anyone point me in the right direction please?

    Many Thanks

  2. #2
    FLAC freeflashstuff's Avatar
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    Have you tried grounding directly to the battery? Some say that helps.
    I have bad luck with vehicles...

  3. #3
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    Connect + and - directly to battery, chassis of amp to chassis of car. Keep the power cables as far from the engine, alternator, and ECU as possible. If you get noise with no input connected there are only a few possibilities: rectifier in alternator going bad, really noisy injectors, or a cheap badly shielded amp. To check if it is the alternator just disconnect the power feed from it or remove the belt, then start the car. Do not connect or disconnect while running, you will most likely pop your regulator. If it is the injectors you can cap and choke each one (check with your local ham radio shop for guidance) but there could be a performance loss. My bet is a cheap amp. The name brands are more expensive for a reason.

    BasketCaseTech

  4. #4
    MySQL Error soundman98's Avatar
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    another thing you can try is to ground the negative rca connection-- it rarely works, but can help drain any voltage on the line to ground.

  5. #5
    Low Bitrate frugmonkey's Avatar
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    strange one i found on my car (vw bora) was that ground to the headunit connector was very poor so it may be worth checking if your using a head unit, i just spliced another ground into the loom and all was well after
    Progress: ~99%
    Fitted, Running.
    boot install to tidy when better weather arrives

  6. #6
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    Hi,

    Thanks for the replies so far! I appreciate it!

    I have tried connecting the earth directly to the battery, chassis & car loom earth all with the same results :-( is it possible to have dirty power?? or is it likely to be a fault with the amp?

    Cheers

  7. #7
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    I am putting my money on the amp. Hard to believe a 600 watt amp in that small of a chassis could be anything but dirty. Reminds me of those Pyramid Gold eq/amps sold in the 80's rated at 300+ watts. They were the size of 2 decks of cards :P

    If you have any old monitor cables or even LPT cables you could try ripping the ferrites off them and putting one over each of the power cables right before the amp. Just cut the plastic case off the big lump in the end of the cable, then e-tape the two halves together over the power cables. That should kill any RFI transferring through the supply lines. If that wont cure it there isn't much filtering you can do to make the amp clean up short of re-engineering the whole works, since the RF is being transferred through the case directly into the amp.


    Oh, one thought... Make sure the amp turn on wire is connected to a clean source also. Try connecting it directly to the power wire instead of through the head unit or antenna circuit. Those remote circuits are notoriously unshielded.

    BasketCaseTech

  8. #8
    FLAC freeflashstuff's Avatar
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    I have bad luck with vehicles...

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