WASAPI talks straight to the audio device.
Hence what you send to it, must match the properties of the DAC exactly.
• 1x RCA coaxial connector SPDIF 32-192 kbps (16-24 bit stereo PCM)
• 2x TOSLINK optical connector 32-96 kbps (16-24 bit stereo PCM)
• 1x USB type ‘B’ connector - Asynchronous data stream at up to 24-bit/96kHz (Determined by source file/computer settings)
24 is the max bit depth supported by your DAC