Brand new AT&T SGS3 and auxiliary to RCA cables.

I've had this device for a week, and aside from some minor annoyances, which I've gotten around, I still can't get the device to work with a majority of auxiliary to rca cables (red and white on one end, 3.5mm on the other end going into the phone), to connect the phone to my home stereo or shelf speakers.

I have a drawer of spare cables, I tried a few different ones I've collected over the years, but nada, nothing. They all still work connecting both a Zune and iPod Classic to speakers, so not sure why the SGS3 isn't working.

Maybe something in device settings?