Retrocomputing Stack Exchange is a question and answer site for vintage-computer hobbyists interested in restoring, preserving, and using the classic computer and gaming systems of yesteryear. It only takes a minute to sign up.
I have a 1702 monitor for my C64. I use a cable that splits the video/audio from the C64 to the Red/Yellow/White thing. Something like this. The white cable is the audio. I believe this is an RCA connection.
I have an audio mixer that accepts line level. I would like to take the audio from the C64 to the audio mixer.
Do I simply get a female RCA to 1/4 inch plug? (so something like this).
Yes. What you have on the RCA plug coming from the C64 is line level mono audio. You can connect it to a mixer using an RCA-to-phono adapter that fits your mixer. Often times, the phono jacks on mixers are for stereo input. So you might need an adapter that goes from Left+Right RCA inputs to a phono plug. Just plug the C64 output to either the Left or Right input, and adjust the mixer balance accordingly to filter the unused stereo input.