Hi Amir, thank you very much for the review! Much respect to you and your audiosciencereview team.
The design goal of this module is to get TPA3255 EVM level price/performance but with a signicantly smaller footprint. We also added PFFB implementation built-in, and uses better parts to achieve better sound quality.
We have sent the low power version so that we can achieve the highest 5W @ 4 ohms score, though it can get to 95dB or more SINAD rating if we have used a unity gain buffer and low impedance input resistors. High power version will get 1dB to 3dB lower SINAD score depending on configuration.
The input buffer has a 1.3x gain and uses OPA1656 opamps. Input impedance is 10Kohms so that it can accept most music input source.
It has 10x (20dB) SE, 5x (14dB) Balanced system gain, so that the module can produce a 20Vrms output out of 2Vrms SE / 4Vrms BAL input.
Getting clean 61W before clipping is desirable, it means you'll get consistent performance at different volume levels. Some amps only have 20W clean output and THD levels starts to rise after that.
Edit (Aug 6, 2021): we have fixed the early clipping issue by changing PFFB network values, PFFB and non-PFFB now have the same clipping output power.
Best regards,
Lester