This unit went back to FiiO since I’ve decided to keep my iFi xDSD Gryphon. It’s just better for my use case. The sound quality of the M15S was certainly great but I much preferred listening to the Gryphon with XBass/Xspace engaged on my Vision Ears VE8 custom IEMs.
Details for why I like the Gryphon below…
I thought that I would appreciate having a dedicated DAP that connects to my WiFi as a Roon endpoint, but since I’m also using the source device as an output for my computer while working, LDAC via the Gryphon is a more sensible solution, especially since it has VolumeSync. It allows me to control the device volume from my computer directly, via Roon, via RooWatch and on the device itself. I can seamlessly switch between Roon RAAT and system audio output. Roon will even show the signal path to the Gryphon as lossless. I’m fully aware that not even LDAC or AptX Adaptive HQ are fully lossless, but to my ears, this setup sounds fantastic, as I love the warmth and musicality of the Gryphon.