Hammond organ dating
In contrast to piano and pipe organ keys, Hammond keys have a flat-front profile, commonly referred to as "waterfall" style.
Jimmy Smith's use of the Hammond B-3, with its additional harmonic percussion feature, inspired a generation of organ players, and its use became more widespread in the 1960s and 1970s in rhythm and blues, rock, and reggae, as well as being an important instrument in progressive rock.
The sound on a tonewheel Hammond organ is varied through the manipulation of drawbars.
A drawbar is a metal slider that controls the volume of a particular sound component, in a similar way to a fader on an audio mixing board.
As with pipe organ keyboards, the two manuals are arrayed on two levels close to each other.
Each is laid out in a similar manner to a piano keyboard, except that pressing a key on a Hammond results in the sound continuously playing until it is released, whereas with a piano, the note's volume decays.The selected percussion harmonic fades out, leaving the sustained tones the player selected with the drawbars.