[Bar 21 (A7 Shape #3)] You can see this in two different ways: where scale and chromatic notes are used to approach chord tones; or where the Minor Blues scale (sour) is used in conjunction with Mixolydian (sweet). Both approaches are valid, and should be considered when learning all these lines. For example, are the first four notes of this line a bend to a C# (Mixolydian) followed by three notes from the Minor Blues scale (4, b5, 5)? Or a chromatic ascent from C# (3rd of A7) to E (5th of A7)? Were I to think about it, I’d say I tend towards the latter perspective, while still being aware of the former. The following notes all signify the use of the sour Minor Blues/Minor
EPentatonic scale before resolving to a C# note in a similar manner to the opening part of the line for Shape #1. Finally, note how the final bar contains notes pretty much taken from the A7 chord shape (Diagram 1), apart from the C note (b3 of A), which is used as a chromatic approach to C# (3rd of the underlying A7 chord). [Bar 31 (A7 shape #4)] This line stays pretty much around the notes of A Mixolydian with, as usual, particular emphasis on chord tones (in this case, 1, 3, 5 and b7). The only non-scale note is, once more, a C note being used as a chromatic approach to C# (see previous example).