Hi Gary,
Tony is correct but I will add a few more details.
Amazon music as well as many other music services can be played by the CXNv2 with Chromecast available on Android and Airplay on IOS.
The volume can be adjusted with the CXNv2's preamp which supplies the RCA outs. I will assume that this is the same for the balanced outputs. The digital outs of the CXN can not be volume adjusted being the preamp is bypassed.
My experience shows that RCA outs on the CXN are not as good as the the digital outs with sound quality. This may be out of the scope of your question but just wanted to bring it to your attention.
Here is a link to the owners manual.
https://manuals.cambridgeaudio.com/cxn-v2-network-playerJohn