Coupling cap in input stage

[Arthur Dent]

BTW, the point about dissonant intervals in chords is a good one. All I can say is that no guitar chord I know of contains an interval of a semitone, because the fingering would be hard. The major seventh example you gave will always have the lower note in the m2 moved up by an octave, or the higher one moved down. This inverts the interval so it's a semitone short of an octave. Which oddly enough is a major seventh.

But you can use the m2 in that chord on a piano, and it sounds pretty normal.