Yes - I did select USB as input.

Using the 2014 Macbook (which does not have JRiver loaded), I was able to play iTunes thru the 818v3!! So the USB input works and is recognized by my older Macbook.

Next I tried the 2022 Macbook (this has JRiver) again using the USB-C hub and iTunes would NOT work. In fact, I could no longer see the "Series 800" in the Macbook MIDI App menu - something else went wrong.

Am taking a break by simply listening to iTunes from older MacBook.

Will update later today.

Thanks to all for taking time out to help.

Primary system: 818v3, DSP8000 40th SE, Linn Klimax streamer, Esoteric CD

2nd system: DSP7200, 7200HC, 861v8