I have had to use both the outputs from my Oppo 103; one to my 4k PJ and one to the HD621. This is because the HD621 only passes artifacts in 4k.

Shankar

Oppo UDP-203, Sonos, Nvidia Streamer, Fire TV 4K, Trinnov Altitude32 into Dan D'Agostino Momentum into Wilson Alexx, Paradigm Sub 1, Monitor Audio In Wall surrounds, JVC NX9