# Replacement Stereo Wiring issues



## uk300bake (Mar 16, 2021)

Hello all,
Just purchased a new, well new to me TT Black edition 2011 model. first thing I'm doing is removing the symphony headunit to put in an android screen.
The one I have chose was from amazon and is
https://www.amazon.co.uk/gp/product/B08 ... UTF8&psc=1
Nice looking unit, specifically for my model, steering controls and everything. I am no novice to swapping out stereos but...
I have come unstuck.
This model of head unit outputs the speakers to a standard iso built into the clamp...but I do not have my speakers there, I have a Bose system..
And yes i have searched but don't find what I'm after..
The diagram on the top of my original stereo says that they are the out pins too!!
Any ideas on what to do?
Amazon have said they will return it no issues but will all be the same issue?
Any help or pointing to the right article is appreciated.



20 sided dice online

And the new Harness


20 sided dice online


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## John949 (Apr 12, 2017)

The Audi system uses line outputs to drive the amp. These are marked on the diagram you posted of the green connector. The speaker ouputs from the head unit are not used - hence the loom quadlock section is unpopulated. Your head unit has pins that would connect to the line inputs so I suggest you plug it in and try it. (Don't froget to connect the blue wire from the amp to a 12V that goes live when you turn the radio on: A5 will often work. You may also need to wire a swithed 12V to A7 as the standard radio uses a CAN message to turn on and this pin on the loom is often not connected.


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## uk300bake (Mar 16, 2021)

Moving slowly.
Thanks for the advice..
Pin 5 connected to AMP, sounds like its on full mute, hear a faint sound
Nothing happens on pin 7 though if i add 12v


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## John949 (Apr 12, 2017)

Very sorry, a failed to notice that Audi number their pins differently to the ISO standard.

The pin to turn the amp on is A4 (DSP Ein) on the Audi diagram. This is the famous blue wire and needs to be at +12V to turn the amp on.

If your head unit powers up then don't worry, but if it doesn't then you need +12V on pin 4 (DI Sens).

The A connector section of the Quadlock is laid out like the two standard ISO connectors and the pin functions match the pin positions, however the connectors don't fit and the pin numbering is different - helpful or what?

Your radio seems to be an unbranded version of an Xtrons unit. If it is continues to give troube then I would seriously consider returning it and buying a branded version as these are known to be plug and play in most cases (I have one and it worked ). There are several versions of the Xtrons unit, depending on what processor you want and which facia design you like (they do one that mimics an RNSe). There are also many threads and much info on fitting them.


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## uk300bake (Mar 16, 2021)

Thanks john,

I returned it yesterday..
New one order - 
XTRONS Double Din Android 10.0 Car Stereo Radio DVD Player Octa Core 4G RAM 64G ROM GPS Navigation 7 Inch Touch Screen Head Unit Supports Car Auto Play WiFi OBD2 DVR TPMS Backup Camera for Audi TT MK2

From Amazon.


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## TT'sRevenge (Feb 28, 2021)

uk300bake said:


> Moving slowly.
> Thanks for the advice..
> Pin 5 connected to AMP, sounds like its on full mute, hear a faint sound
> Nothing happens on pin 7 though if i add 12v


Pin 5 in what connector? (Quad-lock, as the name implies, has four different ones).

I'm a little confused as to the problem--are you not getting sound out of the speakers or is something else the issue?

If you have the Bose system you also need to trigger the turn on which is the "DSP EIN" pin IIRC. This should get the 12V amp trigger from the aftermarket HU (typically a blue wire). Note that you will need to do the same for the antenna amp if you want radio but there you need an adapter to get the wire to connect to. Some aftermarket heads have separate amp and antenna remote wires, some just have one.

When you look at the top-left connector in the quadlock (*from the perspective of the diagram on the factory radio*) that connector has the telephone and line-out signals. Each of the "LINE xx" pins are the line outs you'd connect to a centre pin on the corresponding RCA output from your aftermarket HU. So for example front channel white RCA from the HU you'd have to connect to the wires that are in that connector corresponding to pin "LINE FL", etc. There is only one signal ground for those outputs (which you'd connect to any/all of the shields on the RCA outputs). You will need to either get an adapter that plugs in to the car's connector and gives RCAs on the other side; _or_, get some cheap RCA cables, cut them and wire them up manually on the car side, plug in the RCAs on the HU side. _Edit: sorry it looks like your harness you have there does have pins/wires for that connector, hopefully with RCAs on the other side?_

*Note also that some part#s of Bose amps do NOT turn on with +12V on that pin, they turn on via CAN signal from the factory head unit.* In this case I _believe_ you can use VCDS to change the coding in the amp such that it uses the +12V turn on instead but I'm not 100% certain.

See this thread from Vortex (hopefully not against forum rules to post link from other forum?):
https://www.vwvortex.com/threads/bose-a ... g.5645132/

The final problem you may run into is also mentioned in that thread^. The factory line-level signal seems to be quite high compared to low-voltage aftermarket HUs. If your Android unit uses 2V outputs (I believe most do) then you might get only very low audio. If your unit has 4V or higher pre-outs you might get better results, however it may still not be as high a signal as it needs to be.


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