I recommend the Bluesound Node 2i, its built-in DAC is very good, just connect it to your CA-7A preamp line level input.
https://www.crutchfield.com/S-TpfPuHxIALw/p_813NODE2IB/Bluesound-Node-2i-Black.html?XVINQ=GLX&aw...
https://www.crutchfield.com/S-TpfPuHxIALw/p_813NODE2IB/Bluesound-Node-2i-Black.html?XVINQ=GLX&aw...