Beatles - Because: Chord progression

Question

I am currently looking at this tune but I'm a bit confused by a part of the progression.

It seems to be using chords built mostly from the C# harmonic minor scale.

So, my current understanding tells me we could use:

• C#min
• D#min
• EMaj
• F#min
• G#Maj
• AMaj
• CMin

Or extending versions of these (eg G#7)

However, at one point, it goes:

C#m, A7, A13, D/F#, Ddim.

Can anyone help me understand what is going on here?

I thought perhaps the A7 or A13 would be followed by a Dmin (secondary dominant) but is doesn't seem to be the case.

Why do the D/F# and Ddim work?

Any advice appreciated.

Thanks.

Answer 1

You found the one unexpected chord.

See here: http://bostonglobe.com/ideas/2012/07/07/when-computers-listen-music-what-they-hear-when-computers-listen-music-what-they-hear/hzdqdfgsIgEPiWPRe66U8J/story.html

Using Music21, which was designed by Michael Cuthbert and his MIT colleague Christopher Ariza, Harvard physics doctoral student Douglas Mason analyzed Beatles songs, running more than 100 of them under the microscope and discovering that the majority of them were built around one—and only one—highly unexpected chord. “You expect C to appear in a song in the key of C, but you wouldn’t expect a chord that almost never appears in a song in C, like E flat, because it’s really out of key. But the Beatles did stuff like that all the time,” said Mason. “They’ll have a song in major but they’ll bring in a chord from the minor key, and that chord will act as an anchor for the whole song.