I have Volumio 2.729 on Raspberry PI 3b, connected to a DAC Marantz SA KI Ruby via USB.
The DAC has an integrated CD/SACD/DVD transport, so I can burn the .dsf files onto a DVD and play them in their native form, DSD. I have done so with a .dsf file I have bought from highresaudio.com, I can see on the display that, when playing the file from a DVD, it reads DSD 2.8 MHz.
Now when I stream the same file through Volumio the display of the DAC reads PCM352.8k/32, basically the DXD format.
What is happening here? is Volumio converting on the fly the DSD stream into DXD before transmitting it over the USB link to the DAC?
Or is it just a bug of the Marantz DAC?