If you are looking for a simple composite and stereo audio cable for your SSDS3, avoid the Retrobit cable. These cables have the stereo audio wired incorrectly.
I picked one of these up a while back and buzzed out the pins.
Left audio (white connector) is wired to the right audio pin in the din connector and Right audio is tied to the mono audio pin (pin 6). And since the SSDS3 doesn't use the mono audio pin, you don't get any audio from the red/right channel audio of the Retrobit cable.
So if you plug the Retrobit cable into a regular Genesis II/MD II and wonder why it works there...it isn't actually giving you stereo audio.
However the original Sega Genesis II cables have been confirmed working by someone who recently reached out to me about the non working Retrobit cables.