How to Wire a Stereo Jack to Two RCAs - mediacollege Home: Audio: Connections: Stereo Jack to 2x RCA Stereo Jack to 2x RCA When a stereo 1/4" jack is being used for a stereo signal (as opposed to a balanced mono signal), the left and right parts of the stereo signal can be split off to two seperate connectors. How to Wire a Mono Cable to a Stereo Jack | It Still Works Plug the mono plug at the end of the cable into the mono-to-stereo adapter. Plug the cable with the mono-to-stereo adapter into the stereo jack. Play a monaural signal source and listen to the individual speakers. Sound should be coming through each speaker at the same volume level.