Volvo AMP output on factory head units:<BR>Using a standard 6 pin din, with pin 1 to the upper left and going CCW to pin 6 in the middle: <BR>pin 1: FL <BR>pin 2: FR <BR>pin 3: RR <BR>pin 4: common audio ground <BR>pin 5: RL <BR>pin 6: amp turn on (+12V) <BR>Output from this jack is LOW LEVEL “logic” signal. It will not be more than 3 volts. Be sure and use a very high quality shielded 6+ conductor cable for this application. If your cable is not shielded, YOU WILL GET NOISE FROM EMI! Also, using this connection, the internal stereo amp is disabled for each channel used. IOW, you will not get audio from the head unit’s internal amplifier when connected to the low-level amp out connector. FYI, your fader and balance controls will function as normal when using the amp out. <BR>Connectors can be had at Mouser Electronics (www.mouser.com) PT# 174-2611 @ <$2.00 each. Also can get the connectors at Digikey Corp. (www.digikey.com) PT# CP-1060-ND @ $.75 each and for a cool 90-degree right angle plug PT# CP-1360-ND @ $2.75 each. The plug is a standard round DIN, 6-pin male. I will be using a Sony UNILINK 8-conductor cable as the donor/ victim. (Great quality and maintains signal integrity for 18’ length. Oh, and EMI shielded too.) You can also use 2 pair of shielded RCAs for audio signal (4 outputs total) and add an AMP turn-on lead (22 ga stranded is sufficient.) Just it’s a tight fit in the connector body as well as more difficult to make and route. <P>Regarding the high-power output from the amp to the speakers, I used a standard wire harness kit as provided from car-stereo shops. (You know…the ones used to install a non-Volvo head unit into a Volvo without cutting the factory wires…) About $3.00 cost, retail $15.00 at stereo shops everywhere. The harness used for the 850 93-97 will work fine. Even on the 98-2001 70 series for this application! Use the smaller of the two connectors for speaker hookup. Cut the signal wires from the larger connector attaching it to the smaller connector to prevent audio feedback into the head unit! Follow wire nomenclature as provided by the manufacturer of the harness to connect the appropriate channels.<P>Prospero <BR>
Just like to add some info to Prosperos reply.<P>The internal amp is NOT disconnected when the external amp outlet is used. There is still signal available on the head units speaker outputs but the amplifier wire harness bypasses the head unit and connects the speakers directly to the amp. In some models (e.g. the 850) the radios internal amp still drives the dashboard tweeters when the external amp is connected.<P>Note that the SC-900 and SC-901 does not have internal amps (other than the centre speaker amp) so this radio always needs an external amp to work in the car.<P>The DIN connector you describe actually has a seventh pin as well, the shield or sleeve, i.e. that "tube" that surrounds the six pins. This shield is connected to chassis ground which is different than the audio ground on pin 4. This is to reduce problems with EMI. If you examine the original DIN cable you will find that each conductor is individually shielded (also the audio ground conductor) and this shield is connected to this seventh shieild pin (the sleeve).<P>So when you convert from DIN to RCA you must take care to connect the sleeve of the RCA connector/s to the audio ground (pin 4) and not the shield (pin 7) because otherwise you WILL get EMI problems.
Audioguy,<BR>Thanks for correcting me! Anyhow, FWIW, the information was cut and paste from a reply I did about a year ago for a friend with an 850. He was using an SC-811 with OEM amp cable from Volvo. The dash tweeters went out whenever the cable was connected to the amp and head unit. Maybe his unit was strange, who knows. But regarding the rest of the post...thanks for the details. I wasn't in the mood to go so deep into details, just not my bag.<P>Cheers,<BR>Prospero