|The S-video cable doesn't carry any audio so you will need a separate patchcord for that. Are you selecting the correct input on the Marantz?|
Just a suggestion, sometimes it's worth speding a little money instead of tearing your hair out trying to make things work.
If this project is important to you, I would look at buying a video card with an HDMI output for your Mac. Then you would get both audio and video and you know it would be compatable with everything. AND, it would be a true high definition signal. S-Video at best is only going to give you 480i resolution (assuming your in America and using NTSC standards).