First, let's distinguish between a regular DVD disk, and DVD-A. Your receiver will recognize the Dolby Digital and/or DTS 5.1 channel information from just the digital co-ax, but DVD-A disks (as well as SACD) are currently output from the player only in analog form. Therefore, you will need 5.1 sets of connections for DVD-A (and SACD) to carry the analog signals from the player to the receiver.
Be aware that the analog signals from DVD-A do not include bass management information for the low-frequency signals used to drive a subwoofer in home theater. I'm not familiar with the circuit details of your Marantz receiver, but my bet is that you will need a separate bass management component if you want to process a signal for your subwoofer.
Be aware that the analog signals from DVD-A do not include bass management information for the low-frequency signals used to drive a subwoofer in home theater. I'm not familiar with the circuit details of your Marantz receiver, but my bet is that you will need a separate bass management component if you want to process a signal for your subwoofer.