Jocko's Bass Tenor of Living: Electric Bass Scales: "Take the A-Train" is in C.

I've always felt that before students learn to play over chord changes they should learn to play properly, that is to say stylistically, over one chord. "Jazz theory" orthodoxy has students negotiating an obstacle course in which each chord is the tonic of its own "chord scale." Thus an analysis of the changes to "Take The A-Train" might go something like:

C6 (C-ionian)(ionian?!?), D7 (D-whole-tone or D-lydian b7), Dm7 (D-dorian), G7 (G-mixolydian), C (C-ionian), A7 (A-altered dominant), Dm (D-dorian), G7 (G-mixolydian)...

…and so on, resulting in a lot of unnecessary labor for the misguided jazz student, and boring solos which display the player's knowledge of "scales and modes" but have nothing to do with how we naturally hear "A-Train." Consider the changes to the bridge:

F | F | F | F | D7 | D7 | Dm7 | G |

And the A-section if you transposed it up a perfect 4th:
F | F | G7 | G7 | Gm7 | C7 | F Dm7 | Gm7 C7 |

In either case, your "jazz improv I" teacher is probably going to suggest that the F-chords be played in F-major (Jamey Aebersold's "F-ionian"). After all, in the first case the F is approached by its dominant C7, in the second F is the tonic of the tune. In freely, naturally realized performances however, the two F-chords must necessarily be different. In the first example, the key of F-major may have been implied by the preceding C7, but is heard and played in the context of a tune in C. It may have been "one of F" for a second, but can't help acting like a IV-chord. The melody of the bridge is indeed very "C-ish":

So as the title says, "A-Train is in C," and certain alterations or additions to the C-scale are all that are needed to make the changes. This is not to say that running a big fat scale isn't a lot of fun. For instance, here's one I love to run over the D7 in "A-Train:"

You just don't want to base your whole approach on this type of thing.

We're going to use a 7th-position C-major scale pattern, and a couple of solos by Johnny Hodges (http://youtu.be/puC6PCZi7_w) and Ray Nance (http://youtu.be/hRGFqSkNjHk), both longtime members of Ellington's band, to explore the tune. Here's the scale:

Of course this scale only tells about half the story of playing in C. There's a lot of freedom to playing over the tonic chord of the home key, where blue notes are always an option, and as you can see from looking at Hodges' solo he makes frequent use of the blue Eb and even E-half-flat while playing in what we'd think of as "the key of C-major." With that in mind, take a more expansive look at our 7th-position C-major scale.

(each different fingering of the major scale on your bass will give rise to its own set of these melodic curlicues and idioms)

Now here are the solos, Johnny Hodges' chorus from a live performance with Wild Bill Davidson, followed by Ray Nance's first chorus in a performance with Duke's band.

The D7 chord has a couple of interpretations, sometimes occurring simultaneously, but first let's just look at D7 itself. There is only one note in D7 which is not in C-major, the F#. Why worry about assigning it to a "scale?" Why not just play in C-major with an F#? Your ear will guide you from there.

As you can see, this isn't "D-mixolydian," "C-lydian," or even G-major. Actually, the only thing that changed is that the note F got replaced by a pair of notes: F-F#, resulting in a little bluesy "flip" on F#. This chord in "A-Train" is usually written as D7b5, and it would seem that a whole-tone scale was called for originally. D-whole tone? Why not C-whole tone? It's the same 6 notes! Play the scale starting on your same 2nd finger 4th string C.

The root is D, but our ears never leave the tonal center C. Hodges' D7 in the last A-section even gives a strong impression that, conceptually, he's dropped into C-minor:

(also see " the ladder of thirds" below)

Dominant 7th chords in the II, bII, or IV positions are generally played as D7#11, which contains both the natural and flatted fifth (written enharmonically as a raised fourth). I generally think of these as "non-dominant" dominant sevenths, as they are not directly performing a dominant-to-tonic function.

The earlier "D7#11 chord-scale" aside, a 7#11 chord is the IV of the melodic minor scale, and most of the licks it generates tend to be based on the tonic of that scale.

Try appending this easy-to-remember A-melodic minor shape to your C-major scale:

Note that what might not look good on paper frequently doesn't sound like a mistake in performance. Hodges and Nance sometimes play the whole-tone scale over the D7 while the unaltered fifths appear in the accompaniment, or vice-versa, and the apparent "conflict" passes entirely unnoticed. D7b5 and/or D7#11 both work fine in "A-Train."

Johnny Hodges plays a whole tone lick for D7 (interestingly off a Bb)

and Ray Nance seems to be hearing 7#11 (see measure 3, 11-12)

The II-V-I's

The cadences, and indeed much of the tune appear to be based upon a relatively simple melodic superstructure:

This is reflected in both Hodges' and Nance's solos.
JH, mm 1 - 2

RN, mm 1 - 3

There isn't any reason to think of this as "an Am triad" (except for fingering/visualizing purposes), but rather as a tonic C with 2 notes "in orbit" around it, at the remove of a third. Either or both of the outer notes can also be lowered a half-step, as in the first four bars of the head itself and examples (including the two just above) from the two solos.

RN m 13 - 15

JH m 27 - 28

(Peter Van der Merwe gives a more detailed discussion of what he calls "the ladder of thirds" in his book "The Origin of the Popular Style.")

All that is necessary to articulate the V-chord (G7) is the leading tone B. A half-step approach from the blue-seventh Bb will give it an unmistakable V-chord feel.

JH m 5-7

But it is almost as frequently eschewed, and again, doesn't sound "wrong" at all.

Here's Ray Nance:

and Johnny Hodges:

It's all in C, dig?

The reliance upon motion in thirds gives these solos a basically pentatonic cast, but you also don't want to don't forget the importance of blue notes, bends, glisses, and whatever else you do to give expression to your solo.

Here's C-pentonic, with a little extra on the way back down.