Amazon Music HD uses Windows mixer in shared mode only. The ability to use Wasapi exclusive mode is absent from the Windows app. Both Tidal and Qobuz have had the ability to use exclusive mode for years. As a result Amazon Music HD is not bit perfect, and even if you are receiving a 24/192 stream it will be down sampled to 24/96 if that is your user setting in Windows sounds. Same for up sampling. I use Tidal and Qobuz and find Amazon Music HD to sound inferior to both. Hard to understand why they did not launch with the ability to use exclusive mode with an external DAC.