C70 100 Watt Amp In An 850

castconcrete · Post by **castconcrete** » 14 Feb 2012, 11:39

Hi,

Did a search on this topic, but my weak computer does not like the search method. Does anyone have experience with this installation? How to make the harness or a source for a pre-made harness that would allow the 100w amp for the C70 to be installed with an SC-816 or an SC-901.
Thanks

Post by **fazool** » 14 Feb 2012, 11:51

I did a quick browse and it looks like the SC-816 uses the same wiring arrangement as the HU-613/650/850

There is a post in this forum on S60 audio upgrade where I included the pictures and pinouts for a cable connecting to this head unit. I used an aftermarket amp so didn't need a connector on the other ned. Its pretty simple, though:

You need a 6-pin DIN (not mini DIN) male connector. Then you need a long spool of speaker wire or a premade "speed cable with 6 conductors).

On your amp end, you will need to get the correct connector and solder it on.

I presume you have an amp from a C70 and you are trying to use it?

Where will you mount it?

The S60's have the wiring harness in place already, does your car? If not you will need to make and run an output cable to the speaker connector (which formerly plugged into your stereo HU).

castconcrete · Post by **castconcrete** » 14 Feb 2012, 14:57

Thank you for the quick reply. It is my understanding that in the Gen1 cars (850s and early S/V 70s, that came stock with an amplifier) there is one harness that connects the head-unit to the amplifier. The speaker connection is still made from the head-unit to the various speaker locations. Your up-grade post and your response to my post make it sound as if the speaker output is made from the power amp to the loudspeaker locations.
I realiize that you used an aftermarket amp rather than the C70 amp, and I guess that before I go down this road any farther, that is a question I would need an answer to. In other words, if I located the C70 amp under the passenger seat, would I need only one custom harness for the head-unit to amp location, or would it require that harness as well as an additional harness from the amp location back to the dash to pick-up the speaker wiring from there?
Thanks for any input.

Post by **fazool** » 14 Feb 2012, 16:41

No, I'm sorry for the confusion - let me clarify:

All stereo units have some sort of amplifier. The stock systems all include a low power amplifier that goes directly to the speakers.

You can run this speaker level signal to an aftermarket amplifier if it has "high level" inputs. Then inside the amp, it will lower the "volume" so the signal isn't distorted and then amplify it higher and cleaner.

But, thats the least desirable way because of signal loss and quality issues amplifying from already amplified signals. The more common way is *IF* your stereo head unit also provides low level outputs, also call pre-amp signals. These are cleaner signals but too low to drive a speaker. These run to a bigger more powerful external amplifier - either stock or aftermarket.

Your stereo *does* have both speaker outputs and pre-amp outputs. Whenever an amp is used the pre-amp outs run to the amp, get increased (cleanly) and then the amp sends a speaker-level high output to the speakers.

So, you will unplug the rectangular speaker harness and plug in a new wire to the amp output plug. Run that new wiring to the amplifier inputs. Then run a new set of speaker wires to all your speakers. To make it much easier, the best way is to run a line from the amplifier output BACK to that rectangular harness and connect all the wires there (and then you save the trouble of running new wires all over the car to the speakers.

Good luck