Convert a headphone jack to an output, with the proper adaptor, and get more options. Hooking up a personal stereo with only a headphone jack to a larger home stereo will allow you to enjoy your tunes without headphones. To use a headphone jack to connect to another device with the standard red and white RCA connections instead of a headphone plug, you will need to purchase a Y-adaptor. A Y-adaptor will convert your headphone jack to a RCA output so you can use the headphone jack as an audio output.
Place the 1/8 inch headphone jack on the Y-Adapter into the headphone output on your device. This will be the same output that you put your headphones into.
Plug the red and white plug on the RCA cable into the red and white phono jacks on the Y-Adapter.
Plug the other end of the RCA cable into the input on the other device. Plug the red end of the cable into the red input and the white plug into the white input.