How The Groove Was Won -- Mr. Hammond invents an organ

Laurens Hammond, inventor of the eponymous organ, had built his business on making electrical clocks -- the first Hammond organs indeed have serial number plates from "The Hammond Clock Company". The central part in those clocks was an electrical motor synchronised to the AC grid's frequency. This motor would drive Hammond's baby.

Hammmond started in 1933, taking an old piano's action and hooking various things to it. The patent for the Model A, the first Hammond organ, was then filed on January 19, 1934. The Hammond became an immediate success, even though, around 1938, the company was forbidden by the FTC to claim that a Hammond could accurately imitate a pipe organ.

The Miracle Of Overengineering -- how the Hammond works

Tone generator

Said synchronous motor drives, through a geartrain, a shaft with 91 metal tonewheels, each with a sinusoidally-shaped periphery. Moving past solenoid pickups, the generator thus delivers 91 different sinus tones. The Hammond's pitch varies with the DC grid's frequency, and early-model Hammonds require an elaborate starting procedure involving a special starter motor to get the motor to sync.

For electromagnetic shielding, the generator is mounted in a metal casing subdivided in chambers with two tonewheels inside each chamber.

Manuals, pedals and drawbars

On the underside of each key of the organ's manuals and pedals, there are contacts (nine for manual keys, two for pedal keys) facing so-called bus bars (i.e., nine resp. two rails running the length of the manual/pedalboard). Pressing down a manual key thus closes nine circuits connecting nine tonewheel pickups to the amplifier via the global volume pedal and nine drawbars -- sliders with nine positions (0-8) that regulate the volume of that particular tone. That way, you can mix a tone freely from nine components. (Same goes for the pedals, but with just two drawbars.)

A set of manual drawbars, designated by pipe lengths in feet as in old organ tradition, and with their respective notes when hitting the middle C:

  1. 16' -- suboctave (c), brown
  2. 5-1/3' -- fifth over suboctave (g), brown
  3. 8' -- basis tone, the one you are actually playing (c'), white
  4. 4' -- superoctave (c''), white
  5. 2-2/3' -- fifth over superoctave (g''), black
  6. 2' -- 2nd superoctave (c'''), white
  7. 1-3/5' -- tierce over 2nd superoctave (e'''), black
  8. 1-1/3' -- fifth over 2nd superoctave (g'''), black
  9. 1' -- 3rd superoctave (c''''), white

There are three groups: 16' and 5-1/3'; 8', 4', 2-2/3', and 2'; 1-3/5', 1-1/3', and 1'. As the numbers on the drawbars go from 0 (off) to 8 (full blast), you can note down a registration by jotting down the numbers for thre three groups. A typical Hammond registration looks like "54 6312 778".

Both 61-key manuals, the lower, labeled "GREAT" and the upper, labeled "SWELL", feature a full set of 9 drawbars. (The Name "SWELL" is just tradition. The expression pedal regulates the entire organ's volume.) Between the lower and upper drawbar sets, there are the two pedal drawbars, 16' and 8', for the 25-key (concert models: 32-key) pedalboard, which makes for a bewildering total of 20 drawbars. Side note: This is nothing. Recent Wersi models come with up to 46 drawbars. This is because Wersi use drawbars in the role of faders for the internal mixer, and the biggest Wersi organs come with three manuals.


There is also a strange feature called percussion. When percussion is enabled, pressing a key generates not only the regular drawbar sounds, but also a 'ping' that sounds, well, percussive and decays within a fraction of a second. The 'ping' is either 4' or 2-2/3' in pitch (refered to as 2nd resp. 3rd harmonic percussion), and there is a soft/normal percussion volume as well as a slow/fast percussion decay switch.

Percussion is single-triggered, that is, a key's percussion tone will only sound when all other keys have been completely released beforehand. A percussion run requires a very clean staccato technique.

Vibrato and chorus

Ah, the elusive scanner vibrato. This is the real rocket science about the Hammond. The signal is fed into a delay line with eight tapping points. A rotating air-dielectric capacitor switch, the scanner, shifts the actual tapping point back and forth along the line, so the output signal, as tapped from the line, periodically shifts in pitch. The rotor is driven by the generator shaft, incidentally.

Vibrato is generated by using that signal; chorus is generated by mixing this 'wet' signal with the 'dry' signal from the generator. The scanner vibrato acts as a sweeping filter, by the way, which gives a very slight phaser effect. Vibrato and chorus are controlled by an on/off switch and a six-way switch with settings V1, V2, V3, C1, C2, and C3.

Amplification and the Leslie

Usually, there is an internal tube preamp as well as internal speakers in the Hammond. There is also an (usually) 11-pin Leslie connector to hook up a Leslie. (Go to the Leslie node; it's good.)

Worse Is Better -- the Hammond sound

Assembling a sound

A Hammond registration is determined by the following adjustments:

  • 9 upper manual drawbars (0-8)
  • 9 lower manual drawbars (0-8)
  • 2 pedal drawbars (0-8)
  • Percussion (off/2nd/3rd)
  • Percussion (norm/soft)
  • Percussion (slow/fast)
  • Vibrato/chorus (off/V1/V2/V3/C1/C2/C3)

This makes for an astonishing 1.02e21 of different sounds from a purely mathematical perspective. If you count in the Leslie Chorale/Off/Tremolo setting and the internal/external speakers Main/Echo/Ensemble setting, you even get 9.19e21 sounds.

Well, reality is a bit different. Old-style organ jocks might tell you something about flutes, reeds, strings and diapasons when it comes to Hammond registration, but it's really only a mix of sinusoidal waves, and all sounds fall into a few large groups. Besides, no matter how much the original Hammond Organ Manual waxes on about trumpet and xylophone sounds, you won't care about ca.-1940 registrations to imitate organ registers. This instrument has its own sound, you'll be looking for jazz, rock, soul, blues, gospel sounds etc. etc., and you'll end up adjusting drawbars all the time anyway. No point in setting up and remembering something like 00 6876 540.

The basic Hammond registration is 88 8800 000. That, without any frills (i.e. percussion, V/C and Leslie all off), is the classic Green Onions sound, just a basic tone without fancy harmonics. (It also makes a great Deep Purple sound with heavy solid-state overdrive.) To smooth it out, maybe make it 68 8600 000 -- that, with vibrato 1 and percussion to taste, is the sound of A Whiter Shade Of Pale. To make a clearer sound, try 80 8800 000 or 80 8000 000; both settings do away with the 5-1/3' fifth; to make it even softer, go for 00 8800 000. 88 0000 000 is a low rumble.

These are the basics, and you can add white drawbars to add more brilliance. One usually starts at the top, with that high 1' whistle, so you get something like 88 0000 08, which gives you a neat trick with percussion (see below). To pack on more, go for something like 80 8804 008 or 88 8808 008 (full white bars).

Those black drawbars add slight dissonance and bite to the sound, especially 1-3/5', which is the only tierce drawbar. The 1-3/5' and 1-1/3' are usually pulled as a pair to put on some dirt on top, the 2-2/3' does the same for the middle. To get Uriah Heep sounds, try settings like 88 8868 446 with moderate to heavy tube overdrive.

Try other stuff, too, such as 80 0008 880 or the 'even bar' setting, 80 8080 808. Oh, and of course there's the full organ, flat-out 88 8888 888. Add tube overdrive and you get Gimme Some Lovin'.

Jazz organ makes heavy use of vibrato and chorus, usually plain V/C 3, with fast Leslie. Rock organ usually has slow vibrato (V1), if any, has the Leslie going slow and changing speed for effects and articulation (classic: Steppenwolf's Born To Be Wild, which has a Leslie with the amp wired straight to the bass driver, and the drum spinning up and down all the time). Blues organ is somewhere in between. Fast vibrato (V1 or V2) without chorus tends to sound awkward, somewhat like a home organ, but can fit some songs, such as The Animals' House of the Rising Sun.

Percussion and triggering tricks

As mentioned above, the percussion is triggered by either the 1' (as usual) or the 1-1/3' (on the spinet models) contact. This means that, with percussion active, that drawbar is muted, which means you can unmute it by switching off the percussion.

In typical organ jazz sets, you'll play a setting like 88 000 008 with full vibrato/chorus, fast Leslie and percussion in the A part. Switch off the percussion for the B part and the 1' falls in at full volume.

Percussion is important for jazzy solo lines, but remember it's single-triggered, so play staccato or it won't sound good. Percussion normally isn't the thing for chords, with some exceptions: One is, of course, Purple's Child in Time; the other is standard jazz organ fare: Loud percussion is neat to add play in arpeggios with a mellow sound such as 80 0000 000. Great for comping ballads.


With nine individual contacts under each and every manual key, pressing a key causes the nine drawbar registers to come on sequentially, not all at once. This causes a characteristic 'smack' or 'click'. Its character depends on the key velocity and it has been said that it's different for every organist.

Keyclick is a must especially for jazz organists.


The strong magnetic fields in the tone generator's chambers interact with each other and with the pickups. This causes signals to 'leak' out, 'singing' or even 'grunting' into the wrong pickups, making the sound 'dirtier'. Anti-leakage filters are built into most Hammonds, but due to the tolerancies in making them, their success varies from organ to organ. No Hammond sounds the same.


Overdrive can come from the organ's internal preamp or from the Leslie's amplifier. When pulling out more and more drawbars, a well-adjusted Hammond goes into overdrive somewhere short before the full setting so you can adjust the drive with the drawbars.

Hot Like 91 Wheels -- dates and models
  • 1935 (June) First Hammond (Model A) released
  • 1939 Novachord released, a tube polysynth; arguably cool, but not very successful
  • 1955 B-3 released (the Hammond), M-3 released (its spinet brother)
  • 1959 A-100 released
  • 1961 L-100 and M-100 released
  • 1965 H-100 released
  • 1974-1976 All 'real' Hammonds go out of production
  • 2002 Hammond Suzuki introduce the New B3, a fully electronic instrument that is identical to the B3 in looks and sounds, as even experts admit.

Hammond Suzuki products available today (May 2002):

  • Leslie 122XB
  • Leslie 21
  • New B3
  • XB-1 one-manual budget stage organ ('drawbar keyboard')
  • XB-3 organ
  • XE-1 Compact Hammond organ/entertainer keyboard with optional XLK-1 lower manual, XPK-100 pedalboard and polished-wood STE-1 stand
  • XE-200 spinet organ/entertainment system
  • XH-200 console home organ
  • XH-200SP spinet/console home organ
  • XK-2 one-manual stage organ
  • XM-1 rackmount sound module with optional XMC-1 drawbar controller
  • XT-100 spinet organ/entertainment system

All Hammond products are now sample-based. None of them have got tonewheels.

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