Piano can work as a 2.0 (all frequencies are passed to LR) as a 2.2 (xover frequency is chosen in GUI) and subwoofer has 2 outputs or as a 2.1 (same as 2.2 but subwoofer is mono).

We are using 2 DAC Ic's PCM5142 with integrated DSP. The PurePath software from TI is available for download (registration required) and can be used to create specific filters and other audio functions.

The board will come pre-programed as a 2.1 output (but you can create your own custom design and load it the board and can access the xover frequency directly from linux (we made a small app).

Hardware wise, we have split the digital and analog side with LDOs and we feed the analog side using an extremely capable LDO LT3042 which is having ultra low noise and ultra high PSRR.. Basically each board has 4 LDO (2 for each DAC ic) (note that digital side uses cheaper LDOs).

Of course, on the analog side we used only thin film resistors and poly caps in audiopath.

Features:

Piano 2.1 is a Slave DAC (Slave DACs are compatible with Sparky or Kali)
Dedicated two No’s of 384 kHz/32bit high-quality DAC PCM5142 for best sound quality
Available with different output connectors: 4 x RCA
DAC SNR is 112dB
DAC THD+N @ - 1dBFS are –93dB
Full Scale Output of DAC is 2.1Vrms
Dynamic Range of DAC is 112dB
Sampling Frequency ranges from 8 kHz to 384 kHz. (Sample rate is limited to 192kHz, for subwoofer modes - 2.1 & 2.2)
Ultra-low-noise voltage regulators for optimal audio performance
Integrated EEPRO
M for automatic configuration (with write-protection)
Compatible with OSMC / Max2Play / RuneAudio / Volumio / Moode / PiCorePlayer / PiMusicBox / OpenELEC and others + Roon Ready