I purchased a Crown cdi4000 amp to use for an outdoor 70v speaker setup.  (link). Apologies if this is a basic question, but was wondering if anyone has ever set one of these up with a port and had advice for how to do so?  

I’m wondering:

• Can I get a single RCA to Phoenix connector like this one, hook it to the digital port on the Sonos and then run it to a single channel on the amp?
• Or do I need two of those - one for each analog channel - to hook up to the two channels on the amp.  (in which case I’d use the bridge output to bridge the channels together)

Any advice?

Thanks in advance!