Car Stereos: OEM integration, www pac, line output converter

Question
I have a 2006 durango with the factory nav that was made by alpine. I would like
to amplify the WHOLE system and add a sub, while keeping the factory headunit.
I would like to achieve this without using speaker level out. I know some of the
prongs on the harness have to be line level. Can I tap into those somehow so I
can get 4 channels and a nonfader?

Answer
Hi Mike,

You can find line-level audio signal wires in the factory radio harness in your Durango, but there's a big problem.  The signal wires are just a 2-channel, fixed output--the output level doesn't vary as you adjust the head unit's volume control or fader controls.  This is because the volume and fader functions are handled by the factory amplifier, controlled through the vehicle's data bus system.  Obviously, you won't be able to use the same control system with your after-market amplifiers, and if you just try to link the head unit's outputs directly to an after-market amp, you won't be able to adjust the volume through the head unit's volume knob.

You have a couple options:

PAC Audio makes an amplifier interface specifically for this application; the part number is C2A-CHY.  This interface works with the Chrysler CAN-bus system to produce a 4-channel full-range output that can be adjusted by the head unit's volume control.  Here's a link to the instruction sheet for this product:

http://www.pac-audio.com/PACProductData/C2A-CHY/1_Instructions/c2a-chy_instructi...

Unfortunately, I haven't had the opportunity to try out this interface, so I can't tell you how well it works.

Alternately, you can try to use the speaker-level outputs from the factory amplifier, probably through some sort of processor/summing device like a Rockford 3Sixty. Because the factory amplifier uses separate outputs for the various bass/treble speakers and sub, with built-in equalization and crossovers, a simple line output converter wouldn't work very well in this vehicle.

Hope this helps!

Brian