after reading some of the discussions here, i changed my mind about using an aux input adapter for the factory head unit. i ordered an alpine 9847, along with alpine's aux input adapter, from crutchfield last week. when it showed up this afternoon, i dove right into the installation: http://www.notwithstanding.org....html the first three are of the headunit lit up. you can adjust the colors for the interface (blue, green, amber, or red), and with the amber setting it matches the rest of the dash beautifully (despite my blurry night time photography). in the last picture you can barely see the black cable that i've run under the driver's seat to connect my ipod to. everything sounds beautiful, and navigating through mp3 cd's is relatively straightforward, however i've got one little problem--volume. i've got the moon and tunes package, which includes the factory amp. i connected the head unit to the factory wiring harness, so now i've technically got two amps in line with one another. i can turn the volume up to 2 (out of 30) and it's at a relatively reasonable level, 3 is more like what i'd normally listen at, but by 5 or 6, it's unberably loud. does the factory amp have a volume control? i looked at it for a bit, but i didn't see anything too obvious. it would be nice to be able to turn it down a bit and gain some finer grain control over the volume (preferrably without having to run 6 rca cables under the carpet and to the new head unit to use the pre-amp outputs, assuming the factory amp has rca inputs...).
The amplifier has a "sensitivity control" input, that normally connects to the factory radio. I don't know how it gets used, but maybe you could check that out.On the amplifier, it's on the 24-pin connector, pin A1 (one of the corner pins) the pin color is BK/WH.I would suspect it's the voltage on the pin that affects it, but that's just a theory. Sorry I don't have more details. Good luck!
2005 Platinum Base ManualSide & Curtain AirbagsABSPower PackageTinted Windows"Mods": 'old-style' center armrest, center +12v, wheelskins leather steering wheel, AC/Recirc blue backlight, beeps on keyless entry, dome light switch, AC insulation, PCD10 10-disc CD/MP3 changer, AAI-GM12 AUX audio input, K&N filter, "shark fin" antenna.
There isn't much you can do to adjust the factory amp. It's just a sealed box with two connectors on it. No RCA inputs either. So yes, as you said, you're double-amplifying the signal. A good portion of people in this situation end up pulling out the M&T amp and switching to better speakers, but some people are satisfied with it. As GMJAP says, there is some sort of sensitivity control wire going from the factory unit to the amp, but nobody's sure exactly what it does or how to interface with it.
2003 Vibe GT Lava"He inched his way up the corridor as if he would rather be yarding his way down it.""For a moment, nothing happened. Then, after a second or so, nothing continued to happen." - Douglas Adams...we all miss you
i'm happy enough with the factory speakers, and i'd really prefer to not have to re-run speaker wire to all seven of them. if i just pull the input/output harnesses out of the factory amp, is there a diagram available somewhere of the wires for those two harnesses? it seems like i should be able to make the connections there w/o having to run new wires. or does a pre-fab adapter exist to bypass the amp? i can find factory amp bypass adapters for fords of various years, but i don't see anything for gm.
There are diagrams and harnesses, yes, but if you bypass the factory amp, you either need to replace the speakers or get an aftermarket amplifier. The M&T speakers run at 2 Ohms, the headunit will only support 4 Ohm speakers. Running at 2 Ohms has a lot of potential to damage the headunit, and the speakers.
2003 Vibe GT Lava"He inched his way up the corridor as if he would rather be yarding his way down it.""For a moment, nothing happened. Then, after a second or so, nothing continued to happen." - Douglas Adams...we all miss you
i called crutchfield today, and they're going to send me an adapter of sorts to step-down the signal coming out of the head unit. it will go between the head unit and the factory harness, and has pot screws to adjust exactly how much it's toning things down. hopefully that'll straighten this out.anyone have any experience with an adapter like this? as soon as i get an email with the shipment info, i'll post the proper name and part #.
It's probably the Scoche FA-3 or something like that, little blue box that retails for $20-40. A few people with M&T have them, as I recall..
2003 Vibe GT Lava"He inched his way up the corridor as if he would rather be yarding his way down it.""For a moment, nothing happened. Then, after a second or so, nothing continued to happen." - Douglas Adams...we all miss you
it was a PAC OEM-2. here's the link: http://www.crutchfield.com/S-p...M%2D2it took just a bit of fiddling with the pot screws to get the levels set properly, and now everything works great. big thanks to derek at crutchfield and to everyone else who chimed in with info!