I got an experimental build of Volumio for RockPi S (thanks @ashthespy), internal DAC works fine so I wanted to perform a subjective listening test. I quickly made a 3.5" jack PCB using a breadboard, to wire out LINEOUT pins of the RockPi.
Here the result:
I am positively impressed by the quality of the internal DAC, this setup (Tube Headphone Amp + Bose AE2w) is particularly sensitive with quality of the source. I really enjoyed listening music for a couple of hours, this board is a great fit for tiny Volumio projects, UI responds fast and smooth.
Sooner or later I’ll design a proper HAT for this board, I see great potential.