Looks interesting .. There seemed to be an HDMI in but no reference to it in the review. I'm guessing multiple 4K sources would have to include an extra 4K switch as well.

Cheers
Tom

Main: G61SL, 218, HD621, 2*7200SE, 7200HCSE, M6s, DSW, Apple TV 4K, NUC (Roon server)
Secondary: Wiim Pro, 3200, Audio Core 200
F80