Omitting the a note in the 2nd chord could have been Chopin's correction, introduced together with the changes in the Etude in A major, No. 1. The composer could have considered the chord without a as an improvement, due to a slightly clearer sound, while maintaining both the completeness of the harmonic structure and logics of the voice leading. According to us, it is, however, the engraver's oversight that seems to be more likely here, as in this Etude – same as in the remaining ones, except for the first one – there are no other traces of possible Chopin interventions in GE1, while omissions of a clearly written note in the base text are to be found in the first German edition, e.g., in the Etude in A minor, No. 4, bar 37. The version of GE1 was repeated in EE3, whereas in GE2 (→GE3), the four-note version of the base text was introduced (GC).
Compare the passage in the sources »
category imprint: Differences between sources; Corrections & alterations
issues: EE revisions, Errors in GE, Authentic corrections of GE
notation: Pitch