i have the cd/tape deck in my car and i was wondering how to wire in the amp because it dosent have 2 rca jacks in the back. there was a thing u could buy that had the 2 rca jacks that i needed but i had to hook it up to the 4 speaker wires but there are more that 4 wires going into the back of the deck. anyone kno what to do?

Buy 2 of them or buy one and Use the Y Adaptor for the RCA's and use a 4 channel Amp.

It is kind of hard to find the matching DIN jacks for the Amps.

Not sure if this is what you're looking for but this cable will allow you to connect an aftermarket head unit to the factory amp:

http://www.quickbrickmotorsports.com/prod_dincable.html

Sorry to bump this but,

Does this mean that the amp is separate to the head unit in the 850? I want to put a standard phono output through the built in speakers, hopefully keeping the car as standard as possible to reduce cost and allow me to remove the system and put the 801+Changer system back in when I got to sell the car.

Basically I'm thinking of removing the SC801 in my 850 T5 and replacing it with a 7" LCD touchscreen hooked up to a mini-itx or Mac Mini based system in the boot (trunk in the US?). I'm hoping to setup an mp3 system with gps and bluetooth phone connection with the help from a Electrical engineer friend.
(I'm a computer scientist)

I've got a 740 and I tried doing the DIN but I came to find out the DIN doesn't carry the sound, unless I'm mistaken somehow.

(I had the speaker wires hooked up based on this:

http://www.volvospeed.com/obd2/RCA-preouts2.htm

and I only got audio from the front speakers I hadn't attached to a new amp)

I'm not 100% sure on this but i'm pretty sure factory amps don't push the speakers, they push the head unit....sort of like a pre-amp. if you have an aftermarket deck in your car you don't really need the factory amp.