Hello Tim
I too have the Neodio NR DAC , yes the usb is 16 bit only as I have found out , I purchased a usb to spdif converter for 24/192
however i can only get 24/96 where I understand it can do full 24/192 as per manual. Maybe its my macbook , I would be gratefull for your input ? Thanks. BTW superb sounding dac lovely tonal colours etc very un digital .