Help on wiring an aftermarket HU to factory amp

[H0lD mY d6InK]

     I have done all the research and I might be making things more complicated. As title says, I have an aftermarket head unit, but want to keep factory amp (I have a 95 850 T-5r). I am going Double Din and have already modified it so it will fit. I also have the Volvo 6 pin din adapter so the factory amp will work on the new head unit.  

     My problem is this; #1 Using the factory amp wire harness, wire everything from that harness to the aftermarket head unit wire harness (then also, how the hell do I color code the wires, can't find any wiring diagram on that amp cable harness) and of course the 6 pin din from factory amp to aftermarket head unit

OR

#2 Get the Metra 70-9220 adapter then wire everything off of that harness to the back of the aftermarket head unit harness therefore bypassing the factory amp harness (my next question would be do I need to wire the speaker wires from the Metra harness to the aftermarket head unit wiring harness) and of course the 6 pin din from factory amp to aftermarket head unit

    Someone give me some guidance..... I think I am pretty damn close. I have done a full sound system before in my Camry, but that was me changing everything in the system vs this time changing a few things but keeping factory wiring.

[andyb5]

Honestly, ditch the factory amp. 

The internal amp in your new headunit will sound as good or better (20 years newer technology) than the stock stuff does. 

 

[H0lD mY d6InK]

     I do agree on the 20 years newer tech statement, but I know what hasn't changed is that you want rms watts, not peak watts. The HU I have is only 25 watts rms and 50 watts peak vs the factory amp at 40 watts rms (I have searched all over for schematics on the factory amp, since its it has 40 watts rms it is safe to say it probably has 80 watts peak). That is still much better then the head unit no matter how old.

     I am pretty sure I found a wire diagram of the stereo last night. I labeled everything on the factory amp harness as all the colors change once the speakers harness is plugged into the factory amp harness. I am going to wire it up exactly like the stock system and have the new HU power the front tweeters. If all else fails I will just buy the metra kit and hook that up. All I will be doing is cutting the factory amp harness a bit , but not the speaker harnesses. We shall see

[andyb5]

Pretty sure the stock amp is rated at 4x40 peak; at least that's what my understanding was. Can you share where you found the RMS numbers?

Oh, and my vote is avoid cutting any/all factory harnesses wherever possible, especially for something as simple as a stereo install.

It has been years since I had a stock HU/amp in my car, so my recollection of the wiring scheme is a bit fuzzy at best so I won't try to guide you from memory and mess things up.

[BEJinFBK]

+1 on NOT cutting up the car - That Metra kit is C H E A P.

And you can use the power side for either set-up. Color problem solved.

I'd also consider yarding out the stock amp. And running with the Metra

adapter, it won't be too big a thing to compare the two very easily.

 

[H0lD mY d6InK]

I read somewhere :P, that there were 3 different types of amps all made by Alpine.

The first one in the 850 that was 4v40w.

A slightly later one in the s70/v70 at 4v50w.

Then the last one which was rated 4v100w in the c70 

I was assuming this was rms because no way would the stock system with amp sound this good at this day and age with like 10w rms running everything. The stock HU could probably supply that amount.