A3 8L 2001 1.8T Sport Aftermarket Head Unit Install

MRCAS

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Hello everyone,

I am new to the forum, (having returned to Audi ownership after a gap of some years since parting company with my awesome 80 Sport), and have taken recent ownership of an immaculate 2001 A3 8L chassis 1.8T Sport.

I wish to swap the Audi Chorus radio cassette out for a quality aftermarket headunit without altering the wiring, and I understand that adapter looms are available. The unit has a subwoofer in the rear, 'Bose' branding on the speaker covers and there appears to be an amplifier in the rear.

I would like to make the best of the existing system and would appreciate knowledgeable advice on which adapter loom to buy and any suggestions for plug and play, or easy to fit improvements.

Many thanks,

Murray.
 
To make the best of the existing system you really should stick with the existing HU. Upgrading the HU on the Bose system is unlikely to improve anything and is more likely to cause other issues like interference/popping. If all you are after is iPOD/mp3 support then get a Connects2 adapter or similar. If you want to improve the sound then simply snip the earth wire going to the Bose pin on the back of the HU.
If you are set on changing the HU then ther are 2 adapters available:
1. PC9-404/410 RCA input adapter - links the front & rear pre-outs (RCA's) from the new HU to the input loom of the Bose amp. This is the best method but can cause popping when changing CD track
2. PC9-408 Speaker input adapter - takes the high level speaker outputs from the new HU back down to low level pre-outs using a cheap hi-lo converter and feeds this to the Bose amp. This provides a substandard signal to the Bose amp and can cause alternator whine and hissing. It's a bit like recording a CD to analogue tape, then burning it back to CD from the tape
You will also need a fascia adapter and ISO aerial amp adapter
You will also need to wire in a switched ignition feed as your car only has a permanent live at the HU, so you would have to switch it on/off manually.
 
Last edited:
Hi Andy,

Thank you for that detailed and very helpful response.

I'm going to try all suggested options and see which I prefer.

Many thanks,

Murray.
 
To make the best of the existing system you really should stick with the existing HU. Upgrading the HU on the Bose system is unlikely to improve anything and is more likely to cause other issues like interference/popping. If all you are after is iPOD/mp3 support then get a Connects2 adapter or similar. If you want to improve the sound then simply snip the earth wire going to the Bose pin on the back of the HU.
If you are set on changing the HU then ther are 2 adapters available:
1. PC9-404/410 RCA input adapter - links the front & rear pre-outs (RCA's) from the new HU to the input loom of the Bose amp. This is the best method but can cause popping when changing CD track
2. PC9-408 Speaker input adapter - takes the high level speaker outputs from the new HU back down to low level pre-outs using a cheap hi-lo converter and feeds this to the Bose amp. This provides a substandard signal to the Bose amp and can cause alternator whine and hissing. It's a bit like recording a CD to analogue tape, then burning it back to CD from the tape
You will also need a fascia adapter and ISO aerial amp adapter
You will also need to wire in a switched ignition feed as your car only has a permanent live at the HU, so you would have to switch it on/off manually.

Hi Andy,

I have replaced the Audi Chorus with a new Parrot RKi8400 using a PC9-408, but the unit is not turning on. Can you advise what is amiss here?

Kind regards,

Murray.
 
The new HU requires two 12v feeds, one for the memory and one to switch it on with the ignition. You only have a permanent live on the Audi loom so you either need to connect them both to the permanent live, or wire in a switched ignition on live from the fusebox
 
The new HU requires two 12v feeds, one for the memory and one to switch it on with the ignition. You only have a permanent live on the Audi loom so you either need to connect them both to the permanent live, or wire in a switched ignition on live from the fusebox

Thank you for that Andy. Could you be so kind as to advise if there is a wire on the Audi loom that I can connect with the Parrot loom to achieve this fix and how I can identify it, etc? I don't mind manually turning the unit on and off.

Thank you in advance for your appreciated assistance.

Kind regards,

Murray.