How does a Class A Amp with Ultra-Low THD+N Sound? F5X with PPM THD

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My Error-Correction/Composite F5M thought.
By simulation:
1. PPM THD
2. uV output offset
3. H2 dominant

 

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Balanced BTL Version.
The 2nd picture shows the FFT of half branch OUTPUT to GND
The 3rd picture shows the THD of V(OutP)
The 4th picture shows FFT of V(OutP)-V(OutN) of BTL output
Deminished H2.