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Replacing Concert Head Unit with aftermarket

Discussion in 'A4/S4 forum(B5 Chassis)' started by Blue_Thunder, Jul 19, 2011.

  1. Arrkon
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    Arrkon Midlands regional Moderator Regional Rep

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    Look at the connectors on the back of the stereo (as below):
    [​IMG]

    If the brown connector has:
    8 Wires - Non Amplified, aftemarket HU will be a straight Fit.
    4 Wires - Half Amplified - PC9-401 will be required
    3 or less (or missing) - Full amp - PC9-408 will be required

    :o.k:
    #41
  2. TrisLC
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    TrisLC Member

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    Thanks for the reply, I need to get hold of some keys for the stereo so I can see whats what then.

    What is the box on the nearside of the rear shelf? It looks like it is attached the the speaker, but different to the other side.
    #42
  3. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator

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    PC9-404 is correct if your new stereo has pre-outs.

    Dont use a 401 if you have pre-outs, as it feeds speaker outs into the rear amplifier.
    #43
  4. TrisLC
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    TrisLC Member

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    The new stereo has pre outs so ill grab a 404 cable and take it from there.

    Thanks for the reply :salute:
    #44
  5. TrisLC
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    TrisLC Member

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    Hi

    Got my stereo in this afternoon but can't work out why I have no rear speakers, I've got a half amped setup and have connected the RCA to the rear out out on the headunit, I've connected up the remote and still nothing.

    if I put it on full fade to the rear I and change the headunit settings to sub I can here some base that I'm assuming is through the rear speaks but it sounds more from the boot?

    any help appricated
    #45
  6. TrisLC
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    TrisLC Member

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    Can anybody offer advice?

    also there was a brown wire connected to the rear of the concert that looks like an earth, does this need to be connected in somewhere?

    if I run the blue remove from the pc9 404 lead to the live in would that damage anything?

    really don't want to go through the pain of rewiring rear speaks
    #46
  7. Oranoco
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    Oranoco Well-Known Member

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    Have you connected the preouts to the subwoofer pre-out. My Alpine deck has 3 sets, front, rear and sub? Failing that go through the menu on the deck as the pre-out may be set to sub rather than full range.

    Not subtle and doesn't blend in with the factory dash at all but it's a superb sounding deck so I put up with the looks.

    [​IMG]
    #47
  8. TrisLC
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    TrisLC Member

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    Thanks for the reply,

    Ive got 2 sets of pre outs, one front and one rear/sub. When I turn the sub on via the headunit I can hear a faint thud of base through the rear but no actual sound from the rear speakers.

    I tried to adjust the volumes for the sub yesterday, but might of missed something. It took me a few hours to remove the old unit as the clips had broken.

    My other though would be the remote wire not having enough power through it, but when I disconnect the leads the faint thud stops in the rear so there must be power there?

    I thought the unit was faulty as I have the same stereo in my wifes bus which is also not pushing music out from the rear speakers, but ive swapped them round and still not joy. Even went to halfords this morning to test another unit in my car and it was the same, no rear speakers.

    What a PITA lol wanted to spend time refurbing my wheels this week not messing around with car stereos :sob:
    #48
  9. AndyMac
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    AndyMac Moderator Staff Member Moderator

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    Just to clarify on all the confusion above:
    There are 2 ways to hook up an aftermarket HU to the Audi system, regardless of whether you have Bose or non Bose
    Clean - take RCA's from new HU and connect them to the rear amp or Bose amp, requires PC9-404 or 410
    Dirty - connect the already amplified speaker outputs and convert them back down to line level and then feed these to the amp so they can be re-amplified again by the Audi/Bose amp - requires PC9-401 or 408. This is a horrible method and you will get alternator whine and hiss as a result.

    Speaker outputs = hi level amped output
    RCA/pre-outs = unamplified line level output

    PC9-401 = non Bose speaker input to rear amp (uses hideous hi-lo converter on rear speaker outputs)
    PC9-408 = Bose speaker input to front-rear amp (uses hideous hi-lo converter on front & rear speaker outputs)
    PC9-404 = non Bose RCA input to rear amp, uses rear pre-outs from new HU directly into Audi rear amp
    PC9-410 = Bose RCA input to front/rear Bose amp, uses front & rear pre-outs from new HU directly into Bose amp


    All of the above require the blue flying lead on the adapter to be connected to the "remote on" or power antenna feed from the new HU. This is the 12v trigger that switches on the amp when the HU is on. It is just a trigger for the amps relay so only requires a miniscule amount of current.
    On the non Bose systems you will need to fade to rear quite a bit to balance the puny 2 x 20w power from the rear amp with the new 2 x 50w going to the fronts directly from the new HU.
    #49
  10. TrisLC
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    TrisLC Member

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    Thanks for you input,

    Ive got the 404 cable and its connected up to the extra remote lead on the headunit, Im sure I set the sub to on and increased the volume but Ill check when I finish work.

    Is there a fuse to the amp? If that was blown would that explain the low thud I get rather than sound?

    Many thanks
    #50
  11. TrisLC
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    TrisLC Member

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    Ok, I've checked all connections and all is correct.

    no fuses blown

    I've taken the 404 and swapped the RCA round and still the same. I've turned the sub volume to max etc and still only get sub sounds from the boot area and nothing from the speakers.

    the remote works as it should, so I now have no idea!

    i can't believe I can do most things mechanical and I can't get a simple stereo to work lol
    #51
  12. jas828
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    jas828 Member

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    if its set to sub thats all you will get as the crossover in the stereo will allowing sounds only belowing 70hz for arguments sake you need that output set to full range or try plugging in your outer preout even though its says front just to see if you get full range sound are you sure that rear output is not just sub only if it is is wont put out full range sound ever
    when you say you swapped round rca? did you just swap red and white or swapped to other set of rca plugs completey
    #52
  13. TrisLC
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    TrisLC Member

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    I put the rca in to the front with no sound at all, when I turn the sub off on the headunit there is no sound at all.

    I tried a completely different headunit earlier and got the same results so Its got to be wiring related. I havnt got another 404 lead and ideally I dont want to buy another as they are expensive.

    According to the blurb for the headunit has front and rear pre outs, the rear say R/Sub.
    #53
  14. TrisLC
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    TrisLC Member

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    Some pics of the current set up..

    [​IMG]

    [​IMG]

    If anybody could shed any light that would be great
    #54
  15. AndyMac
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    AndyMac Moderator Staff Member Moderator

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    Sounds like you have the rear pre-outs set to subwoofer, so you will only get low frequencies sent to the rear amp. If you had the rear pre-outs set correctly to full range then you wouldn't get a sub level control available in the menu, it would disappear. Switch it to full range if you want the rears to work. The thud you get is normal
    #55
  16. LibreYLoco
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    LibreYLoco New Member

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    I recently bought a 2002 Audi A3 (8L i think), non bose with a sub woofer in the boot (which makes it half amplified from what i can gather). I am hoping to replace the Audi Concert stereo with a bluetooth one (this one if i do the self install.. http://www.halfords.ie/webapp/wcs/stores/servlet/product_storeId_11101_catalogId_15551_productId_918067_langId_-1_categoryId_212600) but I was quoted a price of €100 for installation and additional parts on top of the head unit price. because money is a bit tight i was considering doing it myself.

    From looking at this it seems like there is a far amount that can go wrong, and i just wanted to know if it is too complicated for a novice like myself. It would be great if comeone could tell me which of the two iso adapters i need (the stereo i am looking at has one rca out), and if someone who has completed the job could break it down into steps that would be even better.

    Thanks...
    M.
    #56
  17. TrisLC
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    TrisLC Member

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    hi I tried to reply to your pm but you have not enabled pm's so won't go through.

    Go into settings on your profile and switch pm on and ill reply

    cheers

    tris
    #57
  18. LibreYLoco
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    LibreYLoco New Member

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    Thanks tris, should have it set up there now!
    #58
  19. TimFr
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    TimFr New Member

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    A bit confused, I have identical set up apart from the brown connector which I have not got?
    #59
  20. TimFr
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    TimFr New Member

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    Why have I not got a brown connector??
    #60

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