"what happens when he puts a pure digital sine wave thought the Wadax dac and how it is reconstructed at the analog outputs."
Still not clear to me. How can a sine wave be reconstructed into anything other than a sine wave?
Perhaps checking the FR for a wide range of amplitudes would be more revealing for such simple manipulation.
Which raises the question: if an algorithm that fits in a very basic DSP can produce a sound with such a strong appeal and working on all types of music, why are other manufacturers not using it? Too honest? Too much respect for their customers?