Hammond organ

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Hammond organ
Hammond l100.jpg
classification Electrophone
keyboard instrument
range C 1 -fis 5
Sound sample see below under Effects
Related instruments


see below under Hammond Organ Musicians

The Hammond organ (also known as Hammond for short ) is an electromechanical organ named after its inventor, Laurens Hammond .

Originally intended as a replacement for the pipe organ , it became an instrument of jazz through its use as an entertainment instrument ; As a cheap replacement for pipe organs in North American churches, it was initially used in gospel music. From there the Hammond organ spread into rock , rhythm and blues , soul , funk , ska , reggae , fusion . However, the Hammond organ could not establish itself as a full replacement for pipe organs.

It was most popular in the 1960s and 1970s. But even today, their distinctive sound or imitations of this sound are widespread in popular music. Over the decades, the Hammond organ (especially the B-3 model in conjunction with a Leslie speaker system ) became an established instrument.

Common to all instruments is the structure with two manuals and a pedal . The range of the manuals and the pedal keyboard are different for the different models. The upper manual is called Swell , the lower manual Great . These names are borrowed from the pipe organ and mean Hauptwerk (Great) and Schwellwerk (Swell).


Laurens Hammond, itself a musician , invented in 1920 for he produced watches an AC - synchronous motor . From 1932 onwards he looked for other possible uses for this engine. Due to the boom in theater and cinema organs and encouraged by a company employee who was an organist in a parish, he came up with the idea of ​​constructing the sound generation principle of the Hammond organ in 1933. Numerous experiments with a piano led him to apply for a patent for this instrument on January 19, 1934. On April 24, 1934, the US Patent Office in Washington, DC awarded him the patent for the packing box prototype under the name Electrical Musical Instrument (US Patent 1,956,350 .) The organ was built on April 15, 1935 by the organist Pietro Yon presented to the public at a press screening in New York's St. Patrick's Cathedral . Henry Ford placed an order for six organs shortly afterwards. Other prominent customers were George Gershwin and Count Basie . Over the years, the organ has developed into an instrument characteristic of certain musical styles, especially in connection with the Leslie loudspeaker cabinet , a loudspeaker box in which the sound is given a floating effect by rotating reflectors (invented by Donald Leslie ). Since 1936 the instrument has been offered successfully in Germany and other European countries, in competition with Edwin Weltes unsuccessful optical sound organ .

The principles used in the Hammond organ to generate the different pitches by means of gears with different numbers of teeth rotating on a shaft at constant speed, additive sound synthesis and operation via an organ console were already implemented in the Telharmonium in 1900 .


View of the tone generator
Elements of the tone generator, look inside

The sound generation of the Hammond organ begins in the so-called generator . In this case, steel rotate tonewheels (English Tonewheel ) having a wavy edge against electromagnetic pickups (permanent bar magnets in coils). Due to the waveform, the edge of the wheel periodically removes and approaches the permanent magnet. This changes the magnetic flux, which induces an alternating voltage in the coil . The shape of the teeth leads to a sinusoidal oscillation, which is further smoothed by a filter circuit, so that an almost ideal sinusoidal shape is created. The generated alternating voltages in the order of magnitude of a few millivolts are then passed through the manuals, the drawbars and the scanner (vibrato and chorus circuit). At the end of the processing chain there is an amplifier stage that amplifies the audio signal so that a loudspeaker can be activated.

Drive the generator

The synchronous motor of a Hammond B-3 with vibrato scanner and flywheels

The generator is driven by a synchronous motor. After ramping up to synchronous speed, the speed of this motor is only dependent on its number of pole pairs and the mains frequency . This can prove to be a disadvantage if the electricity from generators at an outdoor event is not frequency-stable.

Early models have a synchronous reluctance motor with pronounced poles. In models that are operated at 60 Hz mains frequency, a six-pole motor runs at 1200 revolutions per minute, in 50 Hz models a four-pole motor runs at 1500 revolutions per minute. Since these motors cannot start up by themselves, a shaded pole motor is also installed, which must first bring the generator up to speed.

schematic representation of the early synchronous motors

These models have the so-called START-RUN SWITCHES . The START SWITCH is a button that supplies the starter motor with voltage as long as it is pressed. The RUN SWITCH is a switch that supplies the synchronous motor and the amplifier with voltage, and a resistor is connected in front of the starter motor. Starting a Hammond with these two switches should be done as follows according to the operating instructions:

  1. The START SWITCH Press for about 8 seconds.
  2. Switch on the RUN SWITCH and hold the START SWITCH for approx. 4 seconds and then release it.
  3. After about 30 seconds the organ should be ready to play.
    START-RUN switch on a Hammond B-3

The drive motor is elastically connected to the main shaft by a flywheel-spring system in order to decouple it from the rough running (the torque is not constant over one motor revolution).

Later models have self-starting synchronous motors. Only four-pole motors were used here, which run at 60 Hz with 1800 or at 50 Hz with 1500 revolutions per minute. An exception is the X66 model, in which a two-pole motor drives the special tone generator at 3600 or 3000 rpm.

Construction and maintenance

The tone wheel rotates in front of an electromagnetic pickup

The generator contains between 86 and 96 tone wheels with different numbers of teeth. The tone wheels sit on several (48 for the console models and 42 for the spinet models) steel shafts that are mounted in bronze bushings. The magnetic cores of the pickups protrude to the front and back of the generator housing, which is roughly half the width of the entire organ. The volume of the individual tones can be adjusted via the distance between the magnetic cores and the respective tone wheels. The tone wheels are not arranged chromatically along the main shaft according to pitch, but are arranged in chambers of four with the same translation. Two of these chambers, i.e. a total of eight tone wheels, generate the different octaves of the respective tones. The tones are connected to the contacts of the responsible buttons via the wiring (disarmament) . The signal level is a few tens of millivolts.

The bronze bearings require continuous lubrication. This is ensured by a cotton thread (wick) leading to each bearing, which sucks oil through capillary action from an oil channel running in the middle (parallel to the waves) on the upper side of the tone generator. The channel (and also the scanner vibrato) is filled with oil from above via two small funnels. Suitable oil should be topped up at least once a year so that it is a few millimeters high in the funnel.

The motor-tone generator unit is resiliently suspended in the organ housing for acoustic decoupling. For delivery and for larger transports, however, a transport lock should be attached, similar to other devices with spring-loaded masses (record player, washing machine). Tilting the instrument is not a problem. With regard to oiling, however, it must be ensured that only the felt in the oil pan is moistened. Under no circumstances should there be any oil in the pan. Firstly, this would overflow when the organ was tilted, and secondly, “over-oiling” would damage the vibrato scanner.

Rare view of the tone wheels on the underside of the generator

Sound generation

The speeds required for sound generation are provided by gear drives with twelve different ratios. The twelve different speeds at which the tone wheels turn on the tone wheel shafts result in approximately the twelve equally tuned chromatic tones of an octave.

Using the example of an organ that is operated with 60 Hz mains frequency and has 91 active tone wheels and 61 keys (C – c 4 ) per manual, the relationships are explained in more detail: At 60 Hz mains frequency, the motor shaft of the six-pole synchronous motor rotates at 20 Hz (1200 revolutions per minute). The following table shows the twelve gear ratios for this case, the corresponding tones of the lowest octave of the organ (contra octave: keys C to H with the 16 'bolt pulled) with their frequencies and the deviations from the equal pitch:

translation volume frequency deviation
085: 104 Contra-C 32.69 Hz −0.58 cents
071:82 Contra-cis 34.63 Hz −0.68 cents
067:73 Contra-D 36.71 Hz +0.20 cents
105: 108 Contra-Dis 38.89 Hz −0.09 cents
103: 100 Contra-E 41.20 Hz −0.14 cents
084:77 Contra-F 43.64 Hz −0.68 cents
074:64 Contra-F sharp 46.25 Hz +0.03 cents
098:80 Contra-G 49.00 Hz +0.02 cents
096:74 Contra G sharp 51.89 Hz −0.71 cents
088:64 Contra-A 55.00 Hz 00.00 cents
067:46 Contra-ais 58.26 Hz −0.29 cents
108: 70 Contra-H 61.71 Hz −0.59 cents

The organ is tuned to the concert pitch a 1 = 440 Hz.

For each translation, a set of eight tone wheels with different numbers of teeth rotates on four tone wheel shafts (two tone wheels each sit on a shaft to which they are elastically coupled) to generate the different octave positions of the tones:

octave Number of teeth
Contract octave 002
Great octave 004th
Small octave 008th
Dashed octave 016
Two-stroke octave 032
Three-stroke octave 064
Four-stroke octave 128
Five-stroke octave to f sharp 5 192

For manufacturing reasons, tone wheels with 256 teeth are not used for the five-stroke octave. On the tone wheel shafts for the tones C to E there are toothless wheels without a pickup, which are only mounted for mechanical reasons. Therefore, an organ with 96 tone wheels only has 91 tone wheels, each producing one tone. The tone wheels with 192 teeth for tones C 5 to F sharp 5 are located on the tone wheel shafts for tones F to H. The ratio of 192: 256 teeth is 3: 4, which corresponds to a perfect fourth. Therefore, the tone wheel with 192 teeth on the tone wheel shaft produces the lower fourth of the tone F 5 , i.e. the tone c 5 . However, since the perfect fourth deviates from the equal fourth and there are also other deviations due to the translations, there are other deviations from the equal pitch for the notes of the five-stroke octave:

translation Tonwheel shaft volume frequency deviation
084:77 F. c 5 4189 Hz +1.27 cents
074:64 F sharp cis 5 4440 Hz +1.98 cents
098:80 G d 5 4704 Hz +1.98 cents
096:74 G sharp dis 5 4982 Hz +1.25 cents
088:64 A. e 5 5280 Hz +1.96 cents
067:46 Ais f 5 5593 Hz +1.67 cents
108: 70 H f sharp 5 5925 Hz +1.36 cents

All of the deviations from the equal mood described here are less than two cents, which is generally regarded as the limit of perception for upsets. Thus, the combination of gear drives and tone wheels used represents a sufficiently precise approximation of the equal tuning for musical practice.

Due to the rigid mechanical specification of the frequencies via the different number of teeth on the wheels, the organ cannot become out of tune, but the pitch of the instrument as a whole fluctuates with the mains frequency . A Hammond organ cannot be tuned in any way; all other instruments have to follow it. (This can be remedied by a retrofitted mains frequency converter, which is available in specialist shops.)

The tone generator of the H-100 and X-77 model series is a specialty. It has 96 active tone wheels, twelve wheels with 256 teeth rotate in the top octave. Its pitch range is a full eight octaves, i.e. from C 1 to b 5 or from 32.69 Hz to 7899 Hz. The notes of the five-dashed octave are generated with the same accuracy as those of all other octaves.

Around 1975 Hammond ended the production of organs with electromechanical tone generation and switched to organs with electronic tone generation. However, these organs were initially unable to achieve the typical sound of electromechanical organs, so they were not properly accepted by professional musicians.

Sound shaping

The following considerations apply to the best-known model B-3 ; other models may differ from this without changing the basic principle.

Drawbars and footings

Drawbar of a Hammond organ

A sound of the organ is made up of nine different frequency components together, the respective volume levels on the so-called drawbars (engl. Drawbars ) can be adjusted (see also additive synthesis ). This organ is therefore also called nine-chorus. Each drawbar has nine different loudness levels (from 0 to 8). From this arithmetically, since the zero position of all drawbars does not result in a sounding combination, 9 9 -1 = 387,420,488 different possible combinations.

For ergonomic reasons, the drawbars are arranged in such a way that when playing with the right hand on the upper manual, the drawbars sit on the left because they are operated with the left hand. The drawbars for the lower manual are on the right-hand side.

The drawbars are named after their pitch, expressed by the so-called foot position . This classification was taken from the registers of the pipe organ. The footages are (in the unit of foot , '): 16', 5 1 / 3 ', 8', 4 ', 2 2 / 3 ', 2 ', 1 3 / 5 ', 1 1 / 3 ', 1' . They correspond to the following intervals or overtones based on the base 8 ′ ( equivalent position ):

16 ′ an octave lower ( undertone to 8 ′)
5 1 / 3 ' a fifth higher (3rd harmonic of 16 ′)
8th' Equality
4 ′ one octave higher (2nd harmonic of 8 ′)
2 2 / 3 ' an octave and a fifth higher (3rd harmonic of 8 ′)
2 ′ two octaves higher (4th harmonic of 8 ′)
1 3 / 5 ' two octaves and a major third higher (5th harmonic of 8 ′)
1 1 / 3 ' two octaves and a fifth higher (6th harmonic of 8 ′)
1' three octaves higher (8th harmonic of 8 ′)

A distinction between the fundamental and its octave (footages 8 ', 4', 2 ', 1'; white drawbars), and located between the octave harmonics (footages 2 2 / 3 ', 1 3 / 5 ', 1 1 / 3 ′; black drawbars). Further, there are sub audio tone (footages 16 ', 5 1 / 3 '; brown drawbars). The sub-tones do not belong to the harmonic overtones of an 8-foot register.

In a pipe organ, all overtone registers are always pure, i.e. with frequencies that are an integral multiple of the fundamental frequency. In the Hammond organ, this only applies to the octave registers (8 ', 4', 2 ', 1'; based on 16 '). To fifths (5 1 / 3 ', 2 2 / 3 ', 1 1 / 3 ') and the third (1 3 / 5 to build') in such a way would be for the fifths tonewheels {6; 12; 24; …} Teeth and for the third tone wheels with {20; 40; 80; ...} teeth required, but not there. The fifths and the thirds have to be obtained from the existing notes, which are, however, almost equally tuned. This type of foot position acquisition represents the extreme case of a multiplex organ. All foot positions ("registers") are obtained from a single row of sound generators. The following table shows the tones and their deviations from the purely pitched overtones for the drawbar 2 2 / 3 '(fifth, 3rd partial) and 1 3 / 5 ' (third, fifth harmonic) is:

8′-tone (root) 2 2 / 3 'tone deviation 1 3 / 5 'tone deviation
C. g 0 −1.9 cents e 1 +13.5 cents
Cis g sharp 0 −2.7 cents f 1 +13.0 cents
D. a 0 −2.0 cents f sharp 1 +13.7 cents
Dis ais 0 −2.2 cents g 1 +13.7 cents
E. h 0 −2.5 cents g sharp 1 +13.0 cents
F. c 1 −2.5 cents a 1 +13.7 cents
F sharp cis 1 −2.6 cents as 1 +13.4 cents
G d 1 −1.8 cents h 1 +13.1 cents
G sharp dis 1 −2.0 cents c 2 +13.1 cents
A. e 1 −2.1 cents c sharp 2 +13.0 cents
Ais f 1 −2.6 cents d 2 +13.9 cents
H f sharp 1 −1.9 cents dis 2 +13.6 cents

Note: Because the Cent is a relative measure of the distance between two tones or frequencies, the values of the deviations in the 2 are 2 / 3 'for the drawbar 5 1 / 3 ' and 1 1 / 3 ' .

While the deviations in the fifths are still in the area of ​​the perception limit for detuning, the deviations in the third are clearly perceptible as deviations from the purely tuned major third (5th  partial ), which pipe organ players can find very annoying. On the other hand, this peculiar way of obtaining the feet contributes to the organ's typical sound.

As a notation for register settings, the positions of the individual registers are represented by nine digits in notes or relevant specialist literature. For example, the display 888888888 means that all registers are pulled to the maximum. At 500008000 only the 16 'and 2' registers sound. Often the digits are grouped according to the scheme 2-4-3, so that some organists write down 88 8888 888 or 50 0008 000 for the above examples.

Harmonic foldback

The 91 frequencies of the generator are not sufficient to supply all keys with the complete overtones. This would require 109 frequencies (61 tones plus 3 octaves for the overtones and 12 tones for the sub-octave: 61 + 36 + 12 = 109), some high tones are missing. If you now play a high note, its higher overtones will not sound, which is why it sounds quieter and thinner. The so-called harmonic foldback counteracts this effect. If an overtone is outside the frequency range of the generator, it will sound an octave lower. The Harmonic Foldback is required from note g 5 , as the highest available note on the organ is F sharp 5 . This changes the frequency characteristics of the high tones significantly. The harmonic foldback is the reason a B-3 screams so much in the high registers . The following situation arises for the Harmonic Foldback:

Drawbars Key area: foot position
16 ′ C – c 4 : 16 ′    
8th' C – c 4 : 8 ′    
5 1 / 3 ' C-c 4 : 5 1 / 3 '    
4 ′ C – c 4 : 4 ′    
2 2 / 3 ' C-h 3 : 2 2 / 3 ' c 4 : 5 1 / 3 '  
2 ′ C – f sharp 3 : 2 ′ g 3 –c 4 : 4 ′  
1 3 / 5 ' C-d 3 : 1 3 / 5 ' dis 3 -c 4 : 3 1 / 5 '  
1 1 / 3 ' C h 2 : 1 1 / 3 ' c 3 -h 3 : 2 2 / 3 ' c 4 : 5 1 / 3 '
1' C – f sharp 2 : 1 ′ g 2 –f sharp 3 : 2 ′ g 3 –c 4 : 4 ′

Functionally, the Harmonic Foldback corresponds to an octave repeater in a pipe organ register. However, there is one significant difference to the pipe organ. If a 2 'stop on the g 3 key in the 4' position repeats on a pipe organ , there are also pipes for the highest keys. Together with a 4 'register, you hear 4' + 2 'and from key g 3 4' + 4 ', i.e. two notes simultaneously on each key. Since there are no double tone wheels on the Hammond organ, two different tones only sound up to the key f sharp 3 , namely 4 '+ 2', from the key g 3 only one tone sounds, the 4 '- but this is also here a tone is then made available twice, which results in an increase in volume in the mix (at least theoretically). Especially with the combination 4 '+ 2' + 1 ', the tone becomes increasingly thinner in the higher registers. The Harmonic Foldback therefore does not completely solve the problem of the sound becoming thinner in height.

Chorus and Vibrato

A chorus effect is basically a beat that arises when two tones with slightly different frequencies sound together. Around 1940 this was achieved with a Hammond organ by adding a second tone generator - a chorus generator - which was slightly detuned compared to the main generator. The frequencies of these two generators overlap and a chorus effect is created. Since organs equipped in this way were much heavier, one switched to using a scanner vibrato :

The vibrato unit consists of an analog delay line (or phase shifter circuit, these are series-connected LC and LRC filter circuits) with 16 outputs, at which the audio signal, which is increasingly delayed from stage to stage, is tapped and fed to the vibrato scanner . This is a kind of contactless rotary switch (technically similar to a rotary capacitor with 16 stator packs and one rotor pack).
The signal applied to the stator packs, each delayed to a different extent, is picked up by the rotor and passed on.

The phase-shifted signals are applied to the stator packs with an ascending and descending delay (according to the pattern 1-2-3-4-5-6-7-8-7-6-5-4-3-2-1). Via the rotating rotor coupled to the motor axis, a signal is periodically delayed to different degrees for further amplification. This initially results in a pitch fluctuation ( vibrato ) of the organ tone. If you mix this vibrato signal with the unchanged signal, which is done using the effect level rotary switch , a special chorus effect results , which is known from countless Hammond recordings.


The percussion register is only available on the upper manual, and only on one of the two drawbar sets. The sound and rapid fading of a foot position results in the percussion effect. The percussion does not sound every time a key is pressed, but only when all keys have been released beforehand. The footages 4 'and 2 2 / 3 ' can be switched as a percussion register, a short (about 200 milliseconds) and long (a scarce second) decay time can be selected. In addition, the volume can be switched between normal and soft . The 1'-key contact is used to control the percussion, so the 1'-drawbar is mute when the percussion is switched on.


Hammond organ, Leslie effect Slow-Fast-Slow
Hammond organ, various sequences with Leslie effects

Hammond organs were often equipped with a spring reverb to give the sound more space. In addition, for many, the sound of the Hammond is inextricably linked to the Leslie . This so-called motion sound system is based on the sound of rotating loudspeakers ( Doppler effect ), which causes the well-known wailing of the sound. Oddly enough, Hammond organs were not factory-fitted with a Leslie connector because Laurens Hammond did not like the sound of the Leslie. Rather, it had to be retrofitted with a Leslie Connector Kit . However, from 1967 onwards, smaller Leslie loudspeakers were built into the T and M models.

In hard rock it was and is customary to amplify Hammond organs with guitar amplifiers. Marshall models are popular and widespread. Jon Lord shaped this sound style in the 1970s.

Other effects that are used to change the sound are phasers , ring modulators and flangers .


Presets on a B-3, inverted-colored octave on both manuals

In addition to the drawbars, the models with 73 buttons per manual offer so-called presets with which the manufacturer-defined registrations can be called up at the touch of a button. Larger organs such as the B-3 , C3 and A100 offer an entire octave of inverted-colored keys on both manuals with which the presets can be selected. Only one preset can be selected at a time; the button then locks in the pressed position. The drawbars do not adjust themselves automatically because there is no motorization, the presets are rather internally wired.

Other models offer toggle switches as presets. These include the M-100 and L-100 series from Hammond.

Model types

There are basically two types of Hammond organs:

  • Console models: These have two manuals each with 61 (+ 12) keys (C – c 4 ) and a 25-note (C – c 1 ) or 32-note (C – g 1 ) bass pedal (full pedal). There are also four nine-choir drawbar sets (two per manual) and nine presets per manual. (The colored inverted buttons at the left end of the manual are switches that are used to select the presets and drawbar sets). The bass pedal has two drawbars (16 'and 8'). Console models were intended for concert and church music. They include the technically similar model series A100, B-3 and C3 as well as RT3, D100, E100 and H100 (list incomplete). The "church models" C3 etc. had a lockable cover over the keyboard.
Spinet model TR-200
  • Spinet models: They usually have two manuals with 44 keys each (F – c 3 ), one drawbar set per manual, no or few presets and a twelve-tone (C – H) or thirteen-tone (C – c) stub pedal. The lower manual is only seven or achtchörig, ( '5 and 16, the subharmonic register 1 / 3 ') is missing. Spinet models were designed for home use. The most important representatives are the L100, M3, M100 and T100 series.

The console models also have the "Harmonic Foldback", which is not found in the spinet models. In any case, this results in fundamental tonal differences between the two model types.

The main models

Helge Schneider behind a B-3. The depth of the instrument becomes clear.
  • A-100 (1959–1965), B-3 and C-3 (1955–1974): The epitome of the Hammond organ. Sound generation and shaping are identical in these models. The tone generator generates 91 frequencies. All have two manuals with 61 keys each, to the left of which there are eleven other inversely colored keys for nine presets hardwired on a terminal board and two sets of drawbars per manual, a 25-note bass pedal, percussion and scanner vibrato. The A-100 was intended for home use; in contrast to the B-3 and C-3, there is also a spring reverb system, two power amplifiers (main amplifier with 15 watts and hall amplifier with 12 watts output power) and three loudspeakers (2 x 12 "for the Main speaker and a 12 "speaker for the hall amplifier) ​​built in. The B-3 is the concert model and the C-3 is the church model. They only differ in the housing design and are technically identical. Until the final assembly in a housing, it was not possible to differentiate which model it was exactly.

The four turned legs are mandatory for a B-3. The C-3 has fixed side and rear walls; the A-100 and its variants (A-101 etc.) fixed side walls, the rear wall was arbitrary. The A-100 was the "house model" for the living room, with built-in amplification and sound generation.

  • M-3 (1955–1964): The M-3, also known as the “Baby-B3”, is a spinet model with two 44-key manuals and a 12-note bass pedal. The generator generates 86 frequencies. It has nine drawbars for the upper manual, eight for the lower manual and a bass drawbar (16 ′), as well as percussion and scanner vibrato. A special feature is the eighth drawbars for lower manual, the third above the 1'-register, so a 4 / 5 can 'register sound. The M-3 does not have any presets, but has a built-in 12 watt amplifier and speaker.
  • M-100 (1961–1968): This is a further development of the M-3. It also has presets, reverb, some additional switches for the chorus effects and a 13-note bass pedal. The built-in amplifier controls two loudspeakers, and there is a third loudspeaker for the reverb effects. Nevertheless, the M-3 is the better instrument for many organists because the M-100 does not have a so-called waterfall keyboard like the B-3. A well-known example of using the M-100 is the hit A Whiter Shade of Pale by Procol Harum .
Hammond organ from the
T series
  • L-100 (1961-1972): The organ used by Keith Emerson . The L-100 was Hammond's “cheap spinet”. It is technically similar to the M-100, but in contrast to it has no scanner vibrato and only seven drawbars for the lower manual. One variant is the P-100 , an L-100 in a transportable (two-part) housing.
  • T-200: two manuals with 3½ octaves each, no (inverted) preset buttons, 13-note bass pedal. A mechanical Leslie is built into the base of the case. The model without Leslie was called the T-100 , of which there was also a portable version. This was then called TTR-100. A major difference to the other Hammond models mentioned is that the T series amplifiers work with transistors. Due to the non-existent tubes, the organ cannot be distorted / overdriven as nicely as it is known from the other models.

Hammond organ today

Peter Weltner in action on the Hammond SK2
Jimmy Smith , here at his Hammond B-3, is considered to be the innovator of organ playing in jazz.

Successor and owner of the name Hammond has been a Japanese company since 1986 that markets modern Hammond organs in the old style and sound under the company name Hammond-Suzuki . With these, the sound of the tone generator is simulated using digital technology. The German distributor in Setzingen near Ulm still has a specialist workshop for repairing the old models; There are also original Hammond organs in the large sales room.

Some third-party manufacturers also offered and still offer keyboards and sound modules with the Hammond sound and controls, including the companies Clavia (with the models Nord C1 , Nord C2 , Nord C2D , Nord Electro , Nord Stage ), KORG ( CX-3 , BX -3 , CX-3 II and BX-3 II ), Crumar (Mojo) , Ferrofish ( B4000 + ), Roland ( VK-7 , VK-77 ), Oberheim and Kurzweil , some of which achieve a remarkable authenticity of the sound.

Meanwhile, there are also computer programs that try to imitate the sound and, in some cases - for example by means of special drawbar adapters - the playability of Hammond organs; One of the best known is the Vintage Organs software from Native Instruments .

Hammond-Suzuki itself places a certain emphasis on sacred organs (model 935, A-405 and 920). In addition, series with home organs (wooden housing with horseshoe table), the small, mobile and modularly expandable XK series and as a volume model, the B-3 MK 2 , which is optically and acoustically based on the B-3 , and as a stage keyboard Hammond SK2 are offered. All models are based on the digital reproduction of the tone wheel generator sound.

Properties of sound synthesis

For a long time it was not possible to authentically synthesize the special sound of an electromechanical Hammond organ electronically. For this reason, the old electromechanical organs were still in great demand with musicians after production ended. Only with the possibilities and the general availability of sufficiently powerful digital technology was it possible to achieve the goal of a sufficiently authentic sound reconstruction in contemporary organs and keyboards .

The main challenges for the imitation of the sound of the electromechanical tone generation are as follows:

  1. The Hammond organ provides the nine possible partials (footings) via nine separate electrical switching contacts per key. Due to the design, these nine contacts do not close at the same time when a button is pressed - clearly audible one after the other when a button is pressed slowly. This created a kind of touch dynamics: If the key is pressed down slowly, the sound builds up slowly and "softly" from a maximum of nine individual tones. On the other hand, if the button was pressed down quickly, all nine tones sounded almost simultaneously, so that the tone started "harder". (Depending on the age, individual partials can fluctuate or fail due to transition resistances at the contacts, depending on the key.)
  2. Each key contact always generates a slight cracking or clicking noise when a tone is switched on, provided that the sinusoidal alternating voltage applied to the contact is not exactly at the zero crossing when the key is pressed, but in some phase position and passed on to the amplifier. This actually unwanted, but unavoidable cut in the phase creates a pulse-like, broadband signal that is perceived by the human ear as a cracking noise. Actuating the nine contacts when pressing a button creates a "cascade of clicking noises". Depending on how fast a key is pressed, this results in a "smacking" click, the typical "Hammond click".
  3. The individual gears (tone wheels) in the tone generator rotate at the speed defined by the gear, the exact position of their teeth or the angle of the individual gears to each other - and thus the phase position of the sine tones they produce - is not exactly defined structurally, but randomly .
  4. Every single tone wheel (in connection with some passive components) already delivers a sinusoidal tone. The sinusoidal individual tones are then mixed together using drawbars and key contacts. This type of tone generation and merging can be referred to as a “single tone filter”. In organs with electronic tone generation, however, the individual tone is initially rectangular or sawtooth-shaped. In order to save costs, the filtering (“conversion”) into a sinusoidal signal does not take place single-tone, but only one filter is used per fifth or even per octave (“group filter”). As a result, the sawtooth or square-shaped individual tones are first merged and then filtered, which frees them from overtones and converts them into a sinusoidal signal. Mixing the unfiltered square or sawtooth waves can lead to intermodulation distortion. On electronic Hammond organs from 1975 and on, and on many other electronic musical instruments, these distortions are immediately audible when more than 10 to 20 keys are pressed at once. There are no longer any clean tones, but rather heavily distorted or crackling noises. The old Hammond organ, on the other hand, was completely free of (audible) intermodulation distortion.
  5. The individual tone wheels did not always run completely round; on the contrary, depending on the age and condition of the organ, they had very slight side or vertical beats. The resulting, usually sinusoidal amplitude and possibly even frequency fluctuations influenced or superimposed the actual sine tone generated by the tone wheel. This “uncleanness” of the individual tone is normally imperceptible to the human ear. The tones generated in the sum contribute precisely because of the impurities of the individual tones to the creation of the special, lively sound image.
  6. A not inconsiderable part of the original Hammond sound is the so-called "leakage noise". This means the crosstalk between neighboring tone wheels in the pickup of the tone wheel currently in use. If you press any key on the Hammond organ with the 8 'drawbar pulled (this is the best way to hear it), you will not only hear the actual sine tone of the 8' position (depending on the condition and age of the organ in question), but also very quietly the tones of other foot positions, which can lead to slightly dissonant sounds of individual foot positions. This "leakage noise" phenomenon occurs very often on Hammond organs built before 1964. The reason for this is that in those years the old wax paper capacitors were still used for the tone generator and the vibrato line box. Over the years, the capacitance value of the capacitors is multiplied by moisture, thus leading to increasingly impure sound and can also lead to a choppy scanner vibrato sound. From about 1964 onwards, so-called “red caps” were built into the organs, the dielectric of which consisted of polypropylene or the like and which could keep the value more stable for decades than their wax paper predecessors. As a result, a Hammond from 1965 onwards had significantly less leakage noise than an instrument from 1963. This can in some cases be simulated on more recent Hammond copies; there are controls like “condition” or “leakage”, with which you can simulate the age and accordingly the sound. However, even this detail function is still not satisfactory, because not every foot position was affected immediately with the old originals and thus the sound was much more variable and random than is the case with today's replicas.

Hammond organ musician

Musicians for whom the Hammond organ was or is style-defining (selection):


The instrument was often played in the radio comedy Eine kleine Dachkammermusik by Hermann Hoffmann .


  • Reinhold Westphal: Hammond organ. In: Oesterreichisches Musiklexikon . Online edition, Vienna 2002 ff., ISBN 3-7001-3077-5 ; Print edition: Volume 2, Verlag der Österreichischen Akademie der Wissenschaften, Vienna 2003, ISBN 3-7001-3044-9 .
  • Hermann Keller: The Hammond Organ . In: Music & Church: magazine for church music . No. 10 , 1938, ISSN  0027-4771 , p. 227-229 .
  • Axel Mackenrott: The Hammond organ: construction and sound . University of Hamburg, Department of Cultural History, 2001 (Master's thesis).
  • Sebastian Bretschneider: Emulation of the tone generator of an electromagnetic organ of the Hammond B-3 type . Hamburg University of Applied Sciences, Faculty of Design, Media and Information, Dep. Technology, Hamburg 2009 (diploma thesis).
  • Joshua Fuchs: Creative handling of the technical limitations of the Hammond organ . University of Music Saar, Saarbrücken 2017 (Bachelor thesis).

Web links

Commons : Hammond Organ  - collection of images, videos and audio files
Wiktionary: Hammond organ  - explanations of meanings, word origins, synonyms, translations

Individual evidence

  1. Patent US1956350 : Electrical Musical instrument. Retrieved on January 17 of 2019.
  2. ^ Power To The Hammond . From sl-prokeys.com, accessed January 17, 2019.
  3. Patent US1956350A : Electrical musical instrument. Published April 24, 1934 , inventor: Hammond Laurens.
  4. ^ Hammond Organ Motors. In: nshos.com. Retrieved January 17, 2019 .
  5. Hammond X66 organ, tone generator. In: nshos.com. Retrieved January 17, 2019 .
  6. electricdruid.net: Technical aspects of the Hammond Organ , accessed January 17, 2019.
  7. ^ History. hammond.at, accessed on January 17, 2019.
  8. See The Complete Hammond Catalog , pp. 50–53, accessed January 17, 2019.
  9. ^ Meet the Hammond T-Series . From captain-foldback.com, accessed January 17, 2019.
  10. hammond.htm . At orgelsurium.ch, accessed on January 17, 2019.
  11. museum.htm . At orgelsurium.ch, accessed on January 17, 2019.
  12. Test report Ferrofish B4000 + on bonedo.de, accessed on January 17, 2019.
  13. sender-zitrone.de
This version was added to the list of articles worth reading on February 27, 2006 .