Hello thanhvo31,
> So be happy with the Pi and Rune
I am happy with my DAC + Pi + Rune
As I wrote, it is a unimportant issue.
> Further, I could not recognize Native DSD vs DoP playback with blind test.
No surprise, because "DSD native" and "DOP" are bitwise identical for the DAC. DOP is packaging of DSD in PCM-frames, only.
It could be more important if DSD256 will become familiar in the future, because (AFAIK) DOP can be used for DSD64 and DSD128, only.
> You need ASIO 2.1 Driver where as Interface support is normally restricted to Microsoft Windows.
I do not believe so, but I can be wrong.
My hypothesis:
"Native DSD" is not bound to Windows with ASIO 2.1/2.2 driver. There are solutions for Linux. You need
1. ALSA lib >= 1.0.28 (o.k. in Rune)
2. MPD with "native DSD"-patch (o.k. in Rune)
3. DAC-specific "quirk" code (availabe/unavailable for TEAC UD-501?)
If you have look at
https://github.com/lintweaker/xmos-native-dsd you see that adaptations are availabe for some DACs. Such an adaptation is product-specific coding in sound/usb/quirks.c (alsa-lib).
But that's my hypothesis, only.