Question by Craig Hedrick
(Belmont, NC, USA)
The “6” and “maj6” symbols are interchangeable and apply only to major triads.
As you are saying, it’s only a good old major chord with the addition of the 6th note (D6 or Dmaj6 = D F# A + B)
Furthermore, when a 6th is added to a dominant 7th chord, we call it a 13th.
For instance if the symbol is C13, the notes implied are : C E G Bb D F A , the A note being the 13th (aka 6th note of the scale).
Does that answer your question?
(please leave a comment here to answer!)