I have ordered a Piano 2.1, for use in combination with Volumio (on RPI3B+)
As TI calls it a miniDSP, I wonder what is possible with the DSP in this DAC and the files that are generated for Volumio.
Is it, for example, possible to create a balanced (or differential) stereo output?
Similar to dual mode, but with the signal output by dac2 inverted.
To answer my own question (I now have the Purepath Studio software)…
Yes, it is possible.
It seems I only have to generate 2 files, give them specific names and write those to a predefined location on the SD card.
I’m still waiting for the delivery of my new Pi (3A+), so I haven’t been able to test it yet, but so far I’m confident it will work 
A bit more research, let’s use this thread as a log
For Dac 0, in 2.1 and 2.2 mode, the systen uses the same bin files,. These files are located in the directory for 2.2.
Dac 1 files are in both the 2.1 and 2.2 folder.
On github I have found a source file that is used to determine the file (location and name) and ‘uploads’ the file to the dac.
I can alter this script so I have to create less files (one per dac, per sample rate.)
It is very likely I will only use one samplerate (96kHz), and have Volumio resample everything.
For now I am considering to create a ‘custom’ directory, that will be a sibling to 2.1 and 2.2
If probing for files, with different filenames (e.g. first 96000-60-0. bin, then 96000-0.bin) fails, the system can fallback to the original location and names.
I have found this thread on DIY Audio: https://www.diyaudio.com/forums/pc-based/310134-raspberry-pi-piano2-1-dac-dsp-volumio2.html
Basically everything I ‘discovered’ was already there…