Originally Posted by FL_Transplant
Ok, two part answer:
1. I have a 'generic' KS-U57 ($7 on ebay) that has the same black box--except I cracked the black box open and found that it is empty (only contains soldered connections). I imagine that the authentic JVC is the same (as you suggested--allows them to charge 100 times more than it's worth). I experience no engine noise due to the generic KS-U57.
2. There's nothing to the pinout--look 'inside' the connector and you'll see three metal contacts close the metal connector (somewhat similar design as a USB jack). The center is common for the line out, and the left/right are the positive for the left and right channels. The metal connector itself is not part of the circuit.
So if you were connecting RCA jacks to it, the outer ('negative') of both RCAs connects to the center contact on the KS-U57, and the center ('positive,' or 'signal') of the left and right RCAs go to the contacts bracketing the center.
KS-U58 and KS-U57 are wired the same.
hey, ive been looking around for the pinout of that plug, unfortunately the only place i can find it online mentioned it's here
i checked my jvc's back plug and it seems like it has more contacts than the 3 you mention above.
i can see two middle contacts (#7 and 8) the round metal contact (#9)and another 6, (#1-6)...
any chance some1 could explain which ones i could use? (yeah i tried to draw it