Aftermarket HU- Do I need CANBUS adaptor?

[StuHolmes]

I have a 2005 A3 Sportback SE with a non-BOSE Concert2, no multi-function steering wheel. Have been thinking about changing the HU as I need mp3 also would like built-in bluetooth.

Really like Beckers Grand Prix units - smart simple OEM look, but @ £300 bit more than I (the wife! ) wants to pay really. Am now considering Blaupunkt Hamburg MP68 as it has all the features I want and the display colour can be changed to red (shame about the big blue spot) and it can be had for less than £200. If anyone has any other suggestions that look good in an Audi and have bluetooth?

Before I go ahead thought I should check out what else I need, was going to get the CANBUS interface till I saw the price (£100!). I read on another forum that the speed signal can be taken from the speedo? the illumination signal from somewhere?! and the switched live from a fuse? Am I right? If someone could confirm where I can find these connections and how I access them!

There is nothing else the CANBUS interface would provide is there? So all I need is a fascia, aerial adapter ?PC5-52 and ISO adapter ??PC9-401
Am I missing something??

 

[AndyMac]

If you go with Becker or Blaupunkt you don't need the PC9-401 as they already use the same 20 pin mini ISO interface as the stock unit.

 

[Oranoco]

Friend of min uses the Becker unit in his A4. It fits in woith the dash a treat. Certainly looks more factory than my Alpine 9812RB

 

[AndyMac]

Also you only need the CANBUS emulator to provide switched live for the HU so it goes on/off with the ignition. You can wire your own one in for about 10p, or just turn it on/off manually.

 

[StuHolmes]

While I was still dithering over the Becker or Blaupunkt I stumbled upon a Dietz canbus adaptor on ebay (£40).
Since then I have now bought a Pioneer DEH-p700bt,

although not as "factory" looking as the becker it is black with buttons and a display which can be changed to red, I think it looks quite good and also has direct control over Ipods and usb devices. I have a 20gb mp3 player sitting around not being used, it will now live in my glovebox!

Now I find out the Pioneer has no inputs for illumination or GALA so all the canbus is supplying is a switched live. Should have listened to AndyMac.

I think I have the wiring situation under control, well nearly. I have a PC9-404 which is for non-bose rear amplified cars. The original wiring in my car has no connections for rear speakers in the iso block, they are connected to the 20pin mini-iso which the harness converts to RCA plugs and also provides a feed to turn on the rear amplifier.
As for the antenna, I have a PC5-90 which includes a feed for the aerial amp which need connecting to the harness also.
I was quite happy with all this and was pretty sure about what to do until I took out the Concert 2 HU....There appears to be two antenna inputs on the Concert, one normal ISO connection and in the middle of the rear is a yellow square plug.

Googling has lead me to believe this is called a "diversity antenna"? and the HU uses whichever is giving the best signal?? Or another forum suggested both antennae use the main input and the smaller ?fakra connection sends a signal back to the switching unit telling it which to use... OR some US sites simply describe them as FM and AM antenna.
Looking for aftermarket adapters has only lead me to adaptors for RNS-e retrofits.

So can anyone tell me what I should be doing with this second lead? Just tie it back and forget about it? Will I get decent reception??