Help fitting my Sony head unit to my Audi A3

[Twigger245]

Ok... so ive read quite a bit about this over the past few hours and I have to say im still confused! I have an Audi A3 2004 model with a Concert head unit, just the standard, no BOSE, Ive been down to halfords and got the wiring kit 'PC9401' and after adjusting the wires have managed to get the headunit to come on and work. However, there is no base whatsoever! The old concert head unit sounded much better! There seems to be (like others have experienced) very little power going to the rear speakers... Ive learnt from other posts that the head unit now just powers the front speakers and the rear speakers and sub are run off an amp in the boot... However, all I could do with is a simple solution based on my situation...... do I buy the lead PC9404 instead? And if I do will this solve the problem and provide power to the rear speakers?

Any help would be greatly appreciated!

 

[MrWhItEwOlF]

Hello Twigger245,

I had the same issue on my A3 which had the concert head unit. I went through about 3 different versions and for the life of me I can't remember which one worked in the end but you need a certain wire loom that connects to both the two small blocks AND the longer block if that makes sense to you?

Also make sure to get a signal booster for your radio signal and connect the blue wire to a live feed to make sure it works

Im sure someone with more knowleadge will be around soon

 

[AndyMac]

PC9-401 is the speaker input version and should only be used if your HU doesn't have rear RCA's. It uses a really cheap hi-lo converter to take the high level speaker outputs from your new HU back down to low level pre-outs to feed the rear amp. This results in unnecesary distortion and interference.
PC9-404 is the correct adapter using the clean rear pre-outs (RCA's)to feed the rear/sub amp but it can't perform magic. Your HU is now delivering over twice the power to the front speakers compared to the stock concert but will still be using the feeble 2 x 20w rear amp to power the rears (and 1 x 50w to the sub). So you will need to fade to rear quite a bit to balance the sound. Ideally you should rewire the rears directly to the HU but this would result in almost no subwoofer at all as it runs off the rear pre-outs.