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Confused with changing standard head unit! (04 plate A3)

Dec Oct 15, 2009

  1. Dec

    Dec Active Member

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    Hey there, been browsing these forums for a while, and finally brought an A3 last week.

    Previously in my old car, I had a Pioneer pop out dvd head unit which simply plugged into the cars loom and worked.

    I want to put this same head unit into my A3 but am confused by what I need and how I will get it to work.

    I have purchased a loom adapter so that the head unit will plug straight in and in theory should work, but I have herd that I need to sort out an ignition live otherwise it will be permanently live and drain the battery?

    Can anyone shed some light on this at all? Is wiring one of the power cables to a fuse in the fusebox going to work and be safe?

    Thanks,

    Dec
     
  2. AndyMac

    AndyMac Moderator Staff Member Moderator

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    You'll need a fascia adapter, antenna amp adapter and yes either twin the ignition on with the perm live (and turn hu on/off manually - it won't drain the battery unless you leave it on) or run an ignition on feed from the fusebox, perfectly safe.
     
  3. Dec

    Dec Active Member

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    Excellent, thanks Andy! Forgot to mention I have the fascia adapter, but didnt realise about the antenna amp adapter! Are the easy to get hold of? (i.e halfords or equivalent?)

    Also is it hard routing a cable to the fuse box?
     
  4. AndyMac

    AndyMac Moderator Staff Member Moderator

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  5. Dec

    Dec Active Member

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    Thanks mate,

    Well this evening I got it plugged in, but have no radio. Thats probably because I dont have that additional white wire thats shown in the pic in that link though.

    Also the standard speakers actually sound worse now, possibly because there is two wiring adapters connecting it to the head unit. Its only the rears that sound bad though :huh:

    Getting annoyed with this and might just put the standard head unit back in and be done with it!
     
  6. Dec

    Dec Active Member

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  7. AndyMac

    AndyMac Moderator Staff Member Moderator

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    Yes if you have the PC9-401 adapter then it will sound pretty bad as it uses a line out converter to take your already amplified rear speaker output back down to pre-out level only to be reamplified back up by the puny Audi amp. So poor quality and possibly buzzing and hiss as well. The PC9-404 uses a straight rear pre-out into the Audi amp.
     
  8. Dec

    Dec Active Member

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    Thanks mate, definately does sound pretty shocking!

    From what i've read, it would be better for me to re-wire the rear speakers direct to the head unit, and then get a new amp/sub for the boot?
     
  9. AndyMac

    AndyMac Moderator Staff Member Moderator

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    Yes definately
     
  10. Dec

    Dec Active Member

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    Excellant, thank you for your help :) Got a friend who's an audio installer and he said he will sort it for me :)

    Would you recomend a CanBus adapter over the adapter and ignition live wireing method?
     
  11. AndyMac

    AndyMac Moderator Staff Member Moderator

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    No waste of time & money, it doesn't provide a proper ignition on (staying live until the keys are out) so you might as well save £50 and just wire one in from the fusebox.
     
  12. Dec

    Dec Active Member

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    So it would operate like the standard head unit? Could be pretty handy if waiting to pick someone up so the ignition doesnt need to be properly turned on :/

    Im just a bit sceptical about adding power wires running through the dash so i'm slightly worried about doing it that way. Ordered one of those circuit adding dual fuse holders to do it, but not sure if it will be safe or not?
     
  13. AndyMac

    AndyMac Moderator Staff Member Moderator

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    No neither a CANBUS emulator or ignition on from the fusebox will give you the correct "stay on until the keys are out". All the CANBUS emulator does is provide an ignition on, so when you kill the engine you will also kill the HU. The only way for it to work like the standard HU is for you to wire in an accessory feed from the actual ignition switch. There doesn't seem to be any fuse on the fusebox that provides this anymore (it used to be Radio S-Kont) so you have to go direct to the source - the ignition switch. On other Audi models this is pretty easy to spot as it's a very skinny red wire among a whole bunch of fat wires, but I haven't done this on an 8P A3 so couldn't guarantee it will be the same. If it is the same then you also need to wire in a relay as the skinny trigger wire has nowhere near the capacity to run the HU, so you just use it to trigger a relay instead using the perm live already at the HU as the source.
    You can't go too wrong on the safety aspect as long as anything you add is fused.
     

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