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Chapter 26 EVB3 483
Hammond also holds the patent for the electro-mechanical spring reverb, still found in
countless guitar amplifiers today!
The Hammond B3 was manufactured between 1955 and 1974. It is the Hammond
model preferred by jazz and rock organ players such as: Fats Waller, Wild Bill Davis,
Brother Jack McDuff, Jimmy Smith, Keith Emerson, Jon Lord, Brian Auger, Steve
Winwood, Joey DeFrancesco, and Barbara Dennerlein. In addition to the B3, there are a
number of smaller Hammond instruments, known as the “spinet” series (M3, M100,
L100, T100). Bigger console models, many of which were designed to suit the needs of
American (USA) churches or theatres (H100, X66, X77, E100, R100, G-100), were also
manufactured.
The production of electro-mechanical organs ceased in 1974. Thereafter, Hammond
built fully electronic organs. Today, people at Hammond-Suzuki are more conscious of
their glorious tradition and produce fine electronic drawbar organs. In 2002, they even
introduced a new digital B3 model which mimics the design and functions of the
classic B3 (except for the weight). The new B3 utilizes a real, mechanical, rotor speaker
cabinet.
Tonewheel Sound Generation
Tonewheel sound generation resembles that of a siren. Of course, there’s no air being
blown through the holes of a revolving wheel. Rather, an electro-magnetic pickup,
much like a guitar pickup is used.
A notched metal wheel, called a tone wheel, revolves at the end of a magnetized rod.
The “teeth” of the wheel cause variations in the magnetic field, inducing an electrical
voltage. This voltage/tone is then filtered, sent through the manuals, amplified, has
vibrato and expression applied to it, and is then amplified.
A long drive shaft is driven by an AC synchronous motor. 24 driving gears are attached
to the shaft, with 12 different gear sizes. These gears drive the tone wheels. The
frequency depends on the gear ratios, and the number of notches in the wheels. The
Hammond is tuned to an almost exact well-tempered scale.
As with pipe organs that feature “multiplexed registers”, the Hammond organ uses
certain generators for more than one purpose. Some high frequency wheels serve as
the fundamental for high notes, and provide harmonics for lower notes. This has a
positive impact on the overall organ sound, avoids detuning and stabilizes levels.