924Board.org

[stevekat]

I am upgrading my factory (I believe) Blaupunkt cassette with a later but vintage Blaupunkt CD player. I want to keep the speaker set up relatively stock and the install simple. All my speaker appear to work OK. Has anyone dealt with the best way to take the left and right front speaker output of a later stereo unit to the single factory dash speaker? I'd like the rear channels to go to the existing left and right speakers.

My preference is to end up with all audio info (L and R) coming into the front speaker, while retaining stereo in the rear. From the little I have been able to find on this, it may not be advisable to combine the two front +'s and -'s. Perhaps Blaupunkt advises on using L or R only? Using positive from one channel and negative from the other? Using some sort of add on mixer board? Is there some easy set of resistors one can hook up?

[924guy]

find a factory console fader and wiring, most people remove these when upgrading their stereos, im sure theres a few people here with one sitting in a box someplace...
_________________
Eric
78 924
82 931 SE "smokey"
99' VehiCross
Y2K Honda Insight
http://www.cardomain.com/id/924Guy
Performance by Pasha

[stevekat]

I do have the original factory fader in place. My impression is that is had three inputs, one for rear L and R, and a single front, and then three similar outputs. I had originally thought the factory radio had two rear outputs and one front output, but as I examine it, it has two front and two rear (L and R respectively.) Does anyone recall if Porsche just tapped off the L or R front speaker output and left the remaining unused? The connections are all factory plug-in - small little two prong plugs with a wide horizontal spade and small round pin.

[Smoothie]

The Porsche OE speaker wiring designs, both w/fader control and without, have one channel of the stereo output feeding the front plus one of the rears, and the other channel feeding the other rear.
Not aware of any way to run both left and right into a single driver without causing problems, other than using a dual voice coil driver. -But as far as I know, only some bass drivers are built with dual voice coils. -But I haven't been too deep into car audio and exactly what's available these days, so check around. If it's made, what you'd want is a dual voice coil midrange or full-range 4x6 oval driver (and of the correct impedance and power handling capacity for your receiver/amp).

Running (+) from one channel to speaker (+), and (-) from the other channel to speaker (-) would still only give you one of the channels' output at the speaker.
_________________
"..it's made in Germany. You know the Germans always make good stuff."


'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

[Smoothie]

I've "chimed-in" on most of the discussions related to this stuff, so a search on "fader" by author "Smoothie" brings up several past discussions - here's one of them - http://www.924board.org/viewtopic.php?t=12465

The OE setup has the rear-left and front speakers on the same channel (left channel, obviously), and the rear-right is on the right channel alone.
The earlier setup (without fader) used 4 ohm speakers at front and rear-left wired in series to put an 8ohm load on the left channel, and an 8ohm speaker was used at rear-right - so the load was balanced at 8ohms per channel.
The later setup with the fader, used 4ohm speakers in all 3 locations, and the fader wiring somehow causes the combined front and rear-left to maintain a 4ohm load. -So the later design runs at 4ohms per channel.
_________________
"..it's made in Germany. You know the Germans always make good stuff."


'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

[El Chato]

Good topic, I plan to do some messing around with the stero but have no fader, does anyone have a a diagram of how to make a fader, so I can install and aftermarket switch?