The 851N can certainly play files at 24-bit/192kHz.
You will simply need to:
- Change the CXN to USB class 2.0 mode. This is done via the Audio settings menu on the front display.
- Install the Audio driver 1.67 on your PC. This can be downloaded here. If you are using a Mac then you simply need to amend your settings. Information on amending your Mac settings can be found here.