Aftermarket HU


Registered User
Jun 15, 2008
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North West
Hi all,

Ive just replacted my OEM Concert HU with an Alpine CDA 9884, got the sub and rear speakers working fine! Ive used an amped aeriel adapter however im still getting breaks in the signal around built up areas!? Any ideas why this is? Do i have to use both of the oem aeriels (only using the round one at the mo)

Ok after a little prodding around with my multi-meter my powered antenna out from my stereo is 10 volts, does anyone know if this is normal, or should it be 12v?
slightly OT, but what car is it in?

im considering using exactly the same HU in an a4 B6 cab, and im a bit worried that the red key illumination and HU screen will look a bit out of place.

which adaptor have you used?

from memory, i think some aerial adaptors have a ground wire that needs to be connected, have you got a decent earth point? this could cause cut outs, but as you say, if the existing system had a dual diversity antenna setup, then it would stand to reason that you need both for adequate reception.
Its in an A3 Sportback. I made my own line out adapter to get the signal from the RCA's on the hu to the stock wiring, and just a normal aeriel amp, which i will have to doctor to accomodate the FALKER plug too! DOH! I might try and attach it to my swithed live instead of the aeriel out as the line is deffo throwing out 12v!

Is there some way of combining the two aerial plugs? does anyone know where the switching of the 2 aerials takes place? is it in the unit in the boot or did the concert HU take both signals and just decide which was best?? im stumped!?

Ive just stumbed across another problem, when i turn my rear demisting on, i get lots of static interferance! Anyone any ideas??? :uhm:
there is an antenna switching control box designated as J515 on the a4 models '03-'05 according to the data i have. i presume there is something similar on the A3. not sure where it is mounted on the a3.

the interference sound like the EMC shielding has been disturbed somewhere along the line. without seeing your wiring, it would be difficult to diagnose. try looking at your wiring for any exposed conductors. you could maybe try running some metal braid over your new wiring and connect it to ground/stereo chassis to try and stop the interference.

how well does the display/button colours match in with the rest of the car?
it looks better in the dark because you dont see the blue buttons as you do in the day, the screen looks good cos it matches the instruments. I'll post up a picture tonight if you want.
that would be great if you can. thanks.

i can send you the pdf info i have on the a4 stereo systems if you need? im not sure what help it may be for your A3, other than showing how the system may be connected together? pm me your email if you want it.
i dont suppose you have a BT car kit hooked in to your unit do you?

im trying to find out how it handles the audio when connected to a non-alpine Bt kit.
I used to have a parrat kit in my ibiza with the alpine and it was excellent, not got the bluetooth unit yet but i will eventually! PM sent! I have got ETKA, however after digging around ive found the switching unit, its got 3 aerial connectors (Fakra) a small plug with 3 wires in it, and 3 separate plugs, one with a thick brown, one with a smaller white and another with a smaller white one! Any ideas whats what?
that looks really smart. thanks for that, i have newfound confidence that it will look ok in the A4.

with regards to the antenna switching unit, i would only be guessing at what the wires do, as i dont know, but i would hazard a guess that one would be for power, one for ground, and the other for remote (turn on) signal.

or could be can-bus hi/lo wiring...
did you use any kind of wiring adaptor for the power/illumination etc?

i know your car is newer and probably more likely to need a can-bus adaptor, but have you lost out on ignition sensing, permanent power, illumination wire or anythign like that?

im trying to work out if i need it on mine. it would bug the hell out of me to not have ignition sensing....
Ive made my own fuse location in the fusebox making use of one of the switched bus bar, ive not bothered with the illumination because it there wasn't much difference when i did have it in the Ibiza. I havent used the can-bus adapter, too expensive! Im still trying to work out how the 2 aerials work together too! Im using the ISO one at the moment with am aerial amp.

Used for the parts to make up the mini ISO plug for the rears, amp and sub. Also used an old RCA lead and some solder sleeves to connect it together!

Let me know if you need anymore pointers!

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