Mozart Four, Hand Sonatos, Vol. I, Sonata In D, K.123a/381, Sonata In F, K.497

'Sources: NEUE MOZART-AUSGABE, Ser.IX/24,Abt.2 (Bärenreiter, Kassel, West Germany); Mozart, Werke für Klavier Zu Vier Handen (G.Henle, München-Duisburg, West Germany). Facsimiles of the autographs and variants from the first editions were also consulted and used for certain passages.
The fortepiano used in this recording is based on the Anton Walter instrument of ca. 1780, which was Mozart's concert instrument. The original is in the Mozart Geburtshaus in Salzburg; the replica was built in 1977 by Philip Belt. It is a typical five-octave Viennese piano of the late 18th century, with knee-levers for raising the dampers and a hand-stop to operate the 'moderator' (a thin piece of cloth brought between hammers and strings to create a special soft effect). Pitch is A-430; tuning is well-tempered, but not equal-tempered.'[discogs]