Sorry, but I have no idea what you're talking about. I don't want to put a computer into the TV room. I don't want to boot up a Mac in order to play music. I don't want to have to turn on the television in order to play music. I do always have my iPhone with me, so something that would allow me to use the iPhone as the controller would be fine.
To be clear, the TV room has wired ethernet. My A/V receiver is an Onkyo TX SR805, about 8 or 9 years old. It does not have wifi. The Apple TV gizmo works fine, except that it requires the TV to be turned on. I want to be able to get the same functionality, while leaving the TV turned off.
The two Marantz boxes seem to give me what I need. Given that the older model can be had for $500, and the newer model for $650, I was just hoping that somebody would be able to tell me what is different between these two devices.