This is the Allegro movement of the Mozart Sonata #6 redone using Thomas Young’s well temperament of 1799, as described by Kyle Gann here..
This is the 1st movement of Mozart’s Sonata #6 K 284, Allegro. It’s scored in the key of A major, unlike the D major in the other movements.
or download here:
Allegro Youngs Well Temperament #2