I tried to use my iPad Pro to provide a digital feed via USB using the Apple Connection Kit (Spotify)
It failed!
Due to the connected device (Ayon CD5S DAC) consuming good much current.
I believe I may be able to overcome this using a USB hub (more expense)
Do I need anything special?
I suspect it needs to be a powered USB hub to avoid current overload issues.
Advice appreciated.

Incidentally I tried the above as neither my MacbokPro or MacPro work with the Ayon - post a version upgrade if the OS (High Sierra)
BUT the CD player works seamlessly with my Windows 10 PC!

Mac used to be plug and play.....(!)