In the treble, alto, and bass clefs, the G♯ in the key signature is placed higher than C♯. However, in the tenor clef, it would require a ledger line and so G♯ is placed lower than C♯.
According to Christian Friedrich Daniel Schubart, A major is a key suitable for "declarations of innocent love, ... hope of seeing one's beloved again when parting; youthful cheerfulness and trust in God."[3]
For orchestral works in A major, the timpani are typically set to A and E a fifth apart, rather than a fourth apart as for most other keys. Hector Berlioz complained about the custom of his day in which timpani tuned to A and E a fifth apart were notated C and G a fourth apart, a custom which survived as late as the music of Franz Berwald.[4]
^Mark Anson-Cartwright (2000). "Chromatic Features of E♭-Major Works of the Classical Period". Music Theory Spectrum. 22 (2): 178. JSTOR745959.
^Peter Cropper, "Beethoven's Violin Sonata in A major, Op.47 'Kreutzer': First Movement", The Strad, March 2009, p. 64
^Rita Steblin (1996) A History of Key Characteristics in the Eighteenth and Early Nineteenth Centuries, University of Rochester Press, p. 123, ISBN0835714187.