A7 E7 B7 A7 E7 B7 1 __________________________________ 2 E ___3____4____5______9____10___11__ 3 C ___3#___4____5#_____9____10#__11__ 4 A ___3#___4#___5#_____9#___10#__11#_ 5 G ___3b___4____5b_____9____10b__11__ 6 E ___3____4____5______9____10___11__ 7 C ___3#___4____5#_____9____10#__11__ 8 A ___3#___4#___5#_____9#___10#__11#_ 9 __________________________________ 10 __________________________________Let's call the A to Bb lever "A", the C to C# lever "C", and the G to Gb pedal "G". We can then use this shortcut notation:
A7 = 3 ACG
E7 = 4 A
B7 = 5 ACG
A7 = 9 A
E7 = 10 ACG
B7 = 11 A
Now here's the other half of the puzzle. You may already know that the C lever (C to C#) makes an A7 chord on strings 2 through 8. If you add the E to Eb pedal P6 into the mix, you can create another complete set of 7th chords.
Let's call the E to Eb pedal "E". In our shortcut notation, the new scheme looks like this:
A7 = 0 C
E7 = 1 CAE
B7 = 2 C
A7 = 6 CAE
E7 = 7 C
B7 = 8 CAE
Pedal 6 doesn't lower string 2 (it raises it to F) so we do lose that string in those CAE positions. Here's the tab:
A7 E7 B7 A7 E7 B7
1 __________________________________
2 E ___0_________3___________7________
3 C ___0#___1#___3#_____6#___7#___8#__ C lever (C to C#)
4 A ___0____1#___3______6#___7____8#__ A lever (A to Bb)
5 G ___0____1____3______6____7____8___
6 E ___0____1b___3______6b___7____8b__ E pedal (E to Eb, P6)
7 C ___0#___1#___3#_____6#___7#___8#__ C lever (C to C#)
8 A ___0____1#___3______6#___7____8#__ A lever (A to Bb)
9 __________________________________
10 __________________________________So again we have this handy thing going on where the I7, IV7 and V7 chords are all clustered together on 3 frets. Now here's the mindblower. When you combine these two systems, you have one of the three seventh chords in the key of E at every fret on the neck!
A7 = 0 C
E7 = 1 CAE
B7 = 2 C
A7 = 3 ACG
E7 = 4 A
B7 = 5 ACG
A7 = 6 CAE
E7 = 7 C
B7 = 8 CAE
A7 = 9 A
E7 = 10 ACG
B7 = 11 A
Amazing, isn't it?
