Door de jaren heen, zijn er diverse veranderingen aangebracht in zowel het áántal toonwielen per model, als het aantal "tandjes" per tandwiel. Hier een aardig overzicht, betreffende deze materie (eng).
91 phonic wheel generator:
This technical change was intended to reduce the cost of manufacturing of the Hammond organ during the second world war. We should not overlook that this technical amendment will have an influence on the sound quality of the organs of this production.
Generator with 91 tonewheels known as "complex":
After the end of World War II, Hammond will return to the manufacture of the Hammond organ with a 91 phonic wheel generator. Changes at the level of the generator with wheels dite 'complex' to the lowest octave which provides additional odd harmonics for the fundamental, this effect will aim to improve the sound of the bass of the Crankset to the level of "16" zipper
Shortly before the introduction of the series B3/C3/RT3 etc, Hammond to redesigned the tone wheel generator to make it slightly narrower. These new generators cannot be used to replace the 91 phonic wheel generator that I described above due to differences in the output terminals. The following models have a 91 phonic wheel generator in a much narrower housing (to be noted that all B3 are fitted with the new narrower generator):
This generator was mounted in the first consoles of type BC, D, E, C... But it was abandoned because of its move of manufacturing for the benefit of the famous chorus vibrato by scanner, much less expensive to produce.
The VIBRATO effect is theoretically defined as single phase modulation, in fact, is almost always attends the association of modulation of the phase and the amplitude of the signal (tremolo).
The sweeping (front & rear) shifts x times 360 degrees, introduces a delay and immediately (also gradually), its cancellation by returning to the starting point, and then cyclically.
The delay is imposed by the speed of movement of the rotor and the calculation of chokes and capacity. These technical parameters are fixed: it is frequency modulation.
On the other hand the modulation of the amplitude that is associated, and which is part of the realism of the vibrato, can be easily increased or decreased by changing the resistance at the end of line.
The CHORUS effect is obtained by inserting a resistor between the "cold" common point of all capacitors and mass. This interposition retards the flow of charges stored in cells LC, (which flow is immediate when the common point of these same condos is grounded).
hus, at each crossing of the rotor, on each cell, it reads a fraction of previously read signal which persists during a small period of time.
A too high value of resistance (me) is equivalent to an open circuit: all scanner static blades are equipotential and obtained a his right "identical" to that of < not channel Vibrato >, to this pres that this ancestor "Circuit transfer of loads" electromechanical we weakened the signal of 25db for the bulk of the frequencies + 15db additional addressing bass... (output scanner; the signal has almost the same amplitude and output Matching Transformer, while it went through a 6AU6 including Av = 100 gain before feedback).
The resulting sound is a thickening of the sound of the note. It is often used when playing chords to magnify the sound of the instrument.
The Hammond chorus is analog. It uses mainly a wheel equipped with 12 contact points that Act on values significantly different delay 12 lines. 3 types of chorus and vibrato are available. A Vibrato that sounds bad, just wants to say that dismantling of the scanner and imposes for a thorough cleaning! View Scanner of VC, the RUN motor and scanning module, the small tray located above the engine is the oil pan:
The V-1, V-2, V-3, C-1, C-2, C-3, the six vibrato and chorus of the B-3 were produced by a rotary scanner, a sort of variable capacitor Rotary steel blade, coupled on the drive shaft primary of the phonic wheel generator and module scan produced variations of phases and amplitudes,inimitable and very coated coloring making vibrato and chorus of the B-3 sound treasure beautifully operates the Hammond lovers.
Following the year of manufacture the switch will have a slightly different form.