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  1. #1
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    Buzzing noise from rear speakers with new head unit

    I know there are loads of posts about similar problems on here but I can't decide what exactly I would need to do for my set-up, sorry!
    So my position:

    I've recently bought an 52 plate S3 and the previous owner swapped the originial Audi tape head unit for a Kenwood one. Details below...

    Previously - Chorus II A3 tape player
    Now - Kenwood KDC 237 cd with aux input
    Also, theres the same standard kit in the back as before, so no change to amp/sub. Not sure what it is but theres a box in the left hand compartment (nothing in the right one), think thats the sub? Don't think its the Bose set-up (ie speakers don't show the bose symbol, etc).

    Theres a strange buzzing noise that comes from the rear speakers, it doesn't get louder or quieter when the vol is turned up or down just a constant buzz. Its not very loud but is starting to get pretty irratating on longer journeys.

    Any ideas on what it is and how to fix it? Simple instructions would be handy as i'm rubbish at electrics.

    Cheers in advance.

    J

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  3. #2
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    Is most likely caused by the line out converter they've used to connect the Kenwood to the rear amp. Pull the HU and have a look at the adapter they've used to connect to the Kenwood to the Audi loom that feeds the rear/sub amp (which is inside the tupperware sub). There are 2 different adapters available. The best one provides an RCA input, so you take the rear RCA's (pre-outs) from the Kenwood and plug those into the adapter. Constant buzzing would point to the fact they've used a speaker input adapter which takes the high power rear speaker output from the Kenwood and feeds that into a line out converter. This takes the high power signal back down to a low level pre-out level, which in turn is fed to the Audi rear amp loom.
    It's easy to spot as they'll be a a bundle of electronics wrapped in foam buried somewhere behind the HU.
    Just trace the speaker cables coming from the Kenwood, there should be the fronts going to a standard ISO brown connector to feed the fronts directly and then the rears which plug into the adapter. The RCA's (phono type plugs) shouldn't be connected to anything. If the RCA's are being used and they have used the correct RCA input adapter then it's gonna be a case of trial and error on earthing the HU properly. Or better still rewiring the rears directly to the HU and using the adapter just for the sub. The Kenwood will be pushing out over twice the power of the puny 2 x 20w amp that Audi use to power the rears, so rewiring is the better option all round.
    The RCA adapter is the PC9-404 or 410 and looks like this:
    http://www.carstereos4u.co.uk/audi-i...63-385086-.php
    Last edited by AndyMac; 18th August 2009 at 15:46.
    "How to tear apart the ties that bind, perhaps fcuk off might be too kind"
    Alex Turner

  4. #3
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    Thanks very much for this advice. The buzz seems to have disappeared now, which is v odd, but great.
    Cheers.

  5. #4
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    Sorry to drag up an old thread, but I have an A3 8P, would the buzzing noise be resolved by using that same adapter to plug the rear speakers into RCA ports?

  6. #5
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    Yes it would
    "How to tear apart the ties that bind, perhaps fcuk off might be too kind"
    Alex Turner

 

 

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