-Each Hammond key has 9 switches, one for each of the nine harmonics on the drawbars. There are 9 conductive bars running along the back of the keyboards
, and these are the busbars
. "Busbar" may also refer to
the wires connected
to the actual busbars
.
As the key is pressed, each switch connects the proper tone for that harmonic on that key to its corresponding busbar. The busbars are then connected to the drawbars, which control the level of each harmonic.
+Each Hammond key has 9 thin metal leaf
switches, one for each of the nine harmonics on the drawbars. There are 9 conductive busbars
, stacked vertically
and insulated from each other, running underneath each keyboard
. The busbars are stacked from
the Sub Fundamental on the bottom busbar
to the 8th harmonic on the top in the same order as the drawbars are arranged from left to right
. As the key is pressed, each switch connects the proper tone for that harmonic on that key to its corresponding busbar. The busbars are then connected to the drawbars, which control the level of each harmonic. If a drawbar is pushed all the way in, any switch on the keyboard which closes on that busbar will not include that harmonic in the tonal mix.
+
+Because there are nine switch contacts under each key and the key rotates through an arc, all nine switches _do not_ close simultaneously. They close somewhat sequentially (and not necessarily in the same order). Which means if a key is "bounced" or "slipped" and not depressed to close all its switch contacts to their busbars, some harmonics may not be heard. This actually enhances the "organic" sound of a tonewheel Hammond. Most clonewheel Hammonds lack this "feature" which is another reason they sound somewhat sterile.
+
+The pedalboards in the console organs are similar but there are four busbars and each pedal closes _two_ switch contacts on each busbar. This "forces" a certain harmonic mix on the pedals that can't be altered as readily as the manuals. The four busbars are mixed by a fixed resistor network and harmonic levels are adjusted by just two drawbars. One drawbar adjusts the level of the Fundamental and 3rd Harmonic and the other adjusts the level of the remaining harmonics (even harmonics, 2nd through 12th). Note that the lowest octave of tonewheels on the console organs are not "hobbed" as sine waves but are more complexly shaped to add tonal color to the pedals
.
