Audi A5 amp pre-outs

[kgthomas]

Hi All,

I have recently purchased a 2012 Audi A5 2.0 Tdi 177 quattro. The car came with the b&o speaker setup.

I currently have 2 12" Alpine R type 2 Ohm dual voice subwoofers. Which I am planning on adding to the car. To power this I have a 2 Ohm stable amp; this is a cheaper American branded amp but has never gave me any problems which is capable of outputting 900W RMS at 2 Ohm. I also have a new set of Vibe QB69 speakers which I am planning on running of another amp I have. These speakers are a few years old but a change of vehicle at the time prevented me from using them.

When I had this setup previously I had a third 12" sony sub also but I am planning on not using it this time and instead just leaving one channel empty on the second amp. On my previous head unit I had three sets of pre-outs (front / rear and sub out).

I am wondering if it is possible to hook up pre-outs to the rear of the radio? The radio is a Concert. And if so is it possible that I have a dedicated sub out pre-out and then a second pre-out to run the other amp?

Thanks in advance for any help offered.

Cheers Keith

[amafzal]

I know the A5 doesnt have a sub even in the B&O option since it doesn't have a rear parcel shelf to house the sub, but here are the pins from the A4 amplifiers (CAN and B&O amps) so have a look at these if they make any sense and match up to the amp pins in the left side of the boot, I am pretty sure the B&O amp in the A5 would be the same as the A4 and the sub pins would be empty so you might be able to plug in a sub directly into the amp, although it would probably have to be a non active sub.

Attachment 30749

The concert radio would not have any am/sub outs as it communicates with the dedicated B&O amp over fibre optic.

[kgthomas]

Hi amafzal,

Thanks for getting back to me about this. Your link doesn't appear to work not unless its cause I don't have enough posts to see it.

I have had a look and I see there is mini ISO plugs sold for these radios MINI ISO ADAPTER Line Out 4 Cinch AUDI CONCERT CHORUS SYMPHONY NAVI PLUS | eBay

It looks similar to the way VDO used to do their pre-outs. I will remove my radio at some stage and see if I have the corresponding connection on the back.

The 2 subs I have are passive but I would doubt there would be enough output from the standard B&O amp to drive them.

Thanks again for taking the time to get back to me.

Cheers Keith

[amafzal]

Well I am not sure if that would work as far as I am aware there is no audio signal transmission from any of the pins but the Fibre optics as it says below from the workshop manuals

'On vehicles with CAN infotainment (Chorus, Concert and Symphony radio systems) the Digital Sound Package control unit -J525 receives the audio signals directly over a line from the radio -R. By contrast, on vehicles with MOST infotainment networks the audio signals are transmitted over the MOST bus.'

I've just read that there may be a CAN based B&O amp too, so first you would need to work out whether you have a MOST or a CAN B&O amplifier in the boot and that can be figured out by the way of seeing if the amp has a fibre optic input attached to it or not. For the two amps I am posting the links for the pin outs so you can work out where the sub can be attached, although your point aroundthe amp not being able to drive the sub, not too sure about that, the factory sub in my A4 is a 8 or 10 inch one so any bigger might struggle.

CAN amplifier - http://workshop-manuals.com/audi/a4_mk3/vehicle_electrics/communication/infotainment/sound_systems/connectors_for_bangolufsen_sound_system_(can)/

MOST amplifier - Connectors for BangÂ*&Â*Olufsen sound system (MMI)

[kgthomas]

Hi amafzal,

Thank you again for the really good post it is really informative and has answered another question I was going to ask where to find a good manual. As I can't find a haynes manual for this car.

I had a quick look this morning on my way into work and it looks like my car uses the CAN system. I think the only way I will know is to plug in the adapter and see if I get a voltage out of it.

The subs I am planning on putting in are 2 12" subs but they are also 2 Ohm subs so will blow most amps as most amps run at 4 Ohm. They also take 450W RMS and 1000W peak so would be well under powered by the factory amp.

Looking at my setup in the car it looks as if there is a separate amp for the sub under the spare wheel as there is a lot of wires running into it.

Hopefully I will be able to get an output from the back of the head unit.

Cheers Keith

[amafzal]

The amp under the wheel should be your B&O amp, although thats not the usual place for it to go, they usually place it in the left side compartment.

If you slide the concert radio out (after having remove the 4 bolts around it), there should be a diagram on the top showing the pins and you might be able to take the audio signals going to the B&O amp, and double them up to go to a separate aftermarket amp for your subs, you'll have to work out the voltage signal coming out at that point to make sure it matches to the amp you have.

Otherwise, go onto ebay and grab yourself a second hand B&O sub removed from an A5, ive seen quite a few on there, and just hook that up straight to the current amp and that should do the job quite well, certainly does a good job in mine (and I dont even have B&O).

[kgthomas]

Yeah I have an amp in the left hand side compartment also. The box under the spare wheel is all enclosed and only looked quickly at it but it had quite a lot of wires running into it. Not unless it is a dual voice coil sub which might explain it.

Yip think the first step is to remove the radio and see what way it is laid out on the rear.

The second B&O sub is an option also.

Cheers Keith

[amafzal]

The box under the spare wheel, just realised and remembered, is the battery!

[kgthomas]

The box under the spare wheel, just realised and remembered, is the battery!

Ah as I said never looked too close at it. I must get a proper look at it.