In order to achieve my master plan of abandoning CDs and converting entirely to digital/wireless music, I need to get an audio stream into my car stereo. It is a Kenwood kdc-mpv619. The front of the stereo has no input jacks. The back has output RCA plugs, but no inputs. The only way to get a signal into the stereo is to use the CD-changer connector. This is a 13-pin DIN connector that contains pins for the audio signals as well as CD changer control signals. Around the year 2001, Kenwood realized that people wanted to use the connector for aux input and started to sell an adapter ( CA-C1AUX ) to convert the 13-pin DIN into a pair of RCA input jacks. Prior to 2001, Kenwood models would not accept audio on the DIN connector until it had established digital communication with the CD changer. I know this because I had to get a CD changer and hi-jack the audio lines for an older Kenwood stereo that I have. Anyway I made a copy of the C1AUX adapter, and also helped myself to the power lines that are supplied in the DIN connector.http://pinouts.ru/Home/kenwood_head_pinout.shtml
The resistor is necessary to indicate that there is something connected, and that the stereo should make "aux" available in its menu of input selections.
So, it all worked fine, but the sound on the G1 was still horrible. No bass. No treble, but there didn't seem to be much distortion. It actually sounded pretty clean.
The next step will be to use a bluetooth receiver to feed audio into the car stereo.