Minshall Organs. Burton Minshall, Canada/USA. 1946

Minshall Organ
‘Mt Vernon’ Minshall Organ

The Minshall range of electronic Organs were designed by the ex-radio repairman Burton Minshall (Born; Dereham Township, Oxford, Ontario, Canada 9th aug 1907 . Died; 10 Feb 1957 aged 49 ).  These electronic tube organs were an early post war design – targeting a new and affluent US middle class and competing with tone wheel, pipe and reed based organs. Numerous electronic organs were produced during the 1950s in what became a fiercely competitive market, eventually dominated by companies such as Hammond, Conn and Gulbranson (who in turn were forced out by heavy competition from Japanese integrated circuit designs in the 1960s).

minshall_01 copy

Minshall’s design was originally intended  as a home build project. This first amateur design eventually lead to the establishment of a successful organ manufacturing company selling mainly to churches and funeral parlours as well as the home organ market.

Minshall’s original plant in Ontario Canada moved in 1946 to Brattleboro, Vermont USA due to the proximity of Estey Organ Co – a well known and established manufacturer of reed organs. In 1947 Minshall’s company merged with Estey to form ‘Minshall-Estey Organ Inc’ where they continued to produce electronic organs based ion Minshall’s designs until 1954 when Minshall severed ties with Estey.

The Minshall company finally came to an end in 1955; Burton Minshall became ill, sold all of his shares in the company and eventually died in 1957.

Vacuum tubes of the MNinshall OPrgan
Tone generator cabinet showing the vacuum tubes and speakers of the Minshall Organ (image copyright Swartko)

The Instruments produced sound using 52 vacuum tubes mostly 12AU7s or 12AX7s – using 3 tubes per tone generator, one as a phase shift oscillator and five sections as RC frequency dividers. The Minshall Organs, which were considerably cheaper than similar competing models, had a reputation for unreliability and problems with pitch drifting of the overheating tubes.

 Minshall Sales Brochure

Article from ‘Mechanix Illustrated’. May 1954.


‘Manufacturing the Muse: Estey Organs and Consumer Culture in Victorian America’. By Dennis G. Waring

‘Mechanix Illustrated’ Magazine. May 1954. H.W.Kellick

The Thyratone. Richard Henry Goldfogle Dorf. USA, 1945

The keyboard of Richard H Dorf's 'Thyratone'
The keyboard of Richard H Dorf’s ‘Thyratone’

Richard H. Dorf (b 14 Mar 1921; d New York, 21 June 1989) was an electronic engineer, prolific author on the subject of vacuum tube electronics and electronic organs, and the head of the Schober Organ Corporation – a supplier of self-build electronic organ kits (using patents licensed from Baldwin organ Co.).

In 1945 Dorf patented the Thyratone which was also supplied in kit form or simply as a circuit diagram and again, in terms of circuitry and filter formant construction, used a design inspired by Winston Kock’s Baldwin Organ .

The Thyratone's seperate tone and amplifier unit
The Thyratone’s seperate tone and amplifier unit

The device was a simple, compact monophonic neon/thyratone vacuum tube instrument similar to the Hammond Solovox and Clavioline family of instruments i.e. designed as a conventional piano extension. The Thyratone was powered by a three octave keyboard with a single sawtooth oscillator for each octave and a series of filters and vibrato effects to colour the tone. The keyboard could be attached to the host-piano keyboard using metal brackets and connected to the Thyratone’s tone generator box, amplifier and loudspeaker via a cable.

Thyratone circuit diagram
Thyratone circuit diagram


Thyratone tone unit and amplifier circuit diagram
Thyratone tone unit and amplifier circuit diagram

Dorf designed as a miniature pipe organ, with familiar stop -based controls for timbre, pitch and vibrato (from another neon tube ‘LFO’); essentially preset setting for the tone filters and vibrato. A foot operated ‘expression pedal’ allowed the player control over the Thyratone’s output envelope.

Schober under Dorf’s supervision continued to develop electronic organ kits – starting in 1954 with valve based organs and moving to transistor organs in the mid 1960s – as well as various peripherals such as the  Schober Tunesmith (1969), The Dynabeat drum machine (1968) and various tape echo units and stroboscopic tuning devices.

Schober Dynabeat, top view showing small percussion pads
Schober Dynabeat, top view showing small percussion pads

Schober Dynabeat drum synthesiser

The Dynabeat was an early solid state transistor based drum machine that was played via pads or a keyboard rather then the usual pre-set rhythms. Percussion sounds included:

  1. Bass
  2. Tom Tom
  3. Woodblock LO
  4. Woodblock HI
  5. Cymbal Brush
  6. Cymbal Crash
  7. Bongo LO
  8. Bongo HI
  9. Snare Drum (when held down does a roll)
  10. Castanets (when held down does a roll)

Tunesmith control panel

Schober Tunesmith

The tunesmith was basically the evolution of the Thyratone but equipped with solid state transistors rather than neon tubes.

dynabeat_popmechandec69-1Like the Thyratone, The Tunesmith was a monophonic 32 note portable mini-organ with a two and half octave range. The basic tone controls allowed the player to switch between different organ voices, trumpet, violin, cello, oboe and flute and modify the note with a variable speed vibrato.


Hugh Davies. The Grove Dictionary of Musical Instruments, 2nd edition, issue Published in print January 2001 | Published online February 2013 | e-ISBN: 9781561592630

‘Electronic Musical Instruments’ by Richard H. Dorf. New York : Radiofile, [1968]

‘Neon Organs’ by Richard H. Dorf . Electronics. p36 August 29, 1958

‘Electronics and Music’ Part IX-X by Richard H. Dorf. Radio Electronics. p39-68 March 1951.

Schober Organ Orphans’ Page

Musser Maestro Marimba Metron. Clair Omar Musser. USA, 1949

Musser’s ‘Maestro Marimba Metron’

“Musser Maestro Marimba Metron” or  “Rhythm Machine” was an early ancestor of the drum machine invented by marimba virtuoso and band leader Clair Omar Musser sometime after 1949. The instrument was  an analogue percussion sequencer designed to accompany Musser’s marimba performances and to teach rhythm to his students at Northwestern University and in his music room at Studio City, California.

The Rhythm machine was a hybrid electronic and electro-acoustic instrument built into an art-deco styled wooden box 18″ wide, 34″ deep, 32″ tall with a top control panel of switches, buttons and dials. The sound was generated using vacuum tube oscillators plus a set of ‘real’ cymbals that were struck with an electro-magnetic solenoid.


The Marimba Metron was able to re-play 13 electronically generated “tempi figures” – rhythmic accompaniments – such as the bolero, waltz, rhumba, cha-cha, tango, samba, and beguine. In addition to the pre-set loops, percussion sounds could be activated using push-button controls. Sounds included  bass drum, tom-toms, temple blocks, woodblock, claves, and maracas sounds, along with the two real cymbals struck by the electronic solenoid.

Clair Omar Musser (1901–1998) Biographical notes

was a marimba virtuoso, a conductor and promoter of marimba orchestras, a composer, a teacher, a designer of keyboard percussion instruments, an inventor, and an engineer for Hughes Aircraft. Musser was born in Pennsylvania and began to study the xylophone in the 5th grade. Upon witnessing a performance of Teddy Brown playing marimba with the Earl Fuller’s Rector Novelty Orchestra, Musser was inspired to study with Brown’s former teacher, Philip Rosenweig. Musser soon became recognized as a virtuoso in his own right, performing as a soloist, with orchestras, and in an early Warner Bros. Vitaphone film.



WDR Electronic Music Studio, Werner Meyer-Eppler, Robert Beyer & Herbert Eimert, Germany, 1951

WDR Electronic Music Studio in 1966

During the 1950s and late 1960s before the advent of affordable electronic instruments, the only organisations that could afford the cost of the equipment and space for dedicated electronic music studios were generally large educational establishments such as Columbia University (USA) or as in this case, national broadcasters such as the state run Westdeutscher Rundfunk (WDR) in Cologne – at the time the largest and wealthiest broadcaster in West Germany. The benefit for these organisations was, on one hand to have a local resource for electronic music and sound effects to use in broadcasting but also, for ‘nationalistic’ reasons; to be see as liberally progressive and technologically advanced. Electronic Music composers remained reliant on their patronage until modular synthesisers became available in the late 1960s.

The Electronic Music Studio at Westdeutscher Rundfunk (WDR) in Cologne was founded by the composers Werner Meyer-Eppler, Robert Beyer, and Herbert Eimert (the studios first director) and was based on Meyer-Eppler’s ideas outlined in his 1949 book ‘Elektronische Klangerzeugung: Elektronische Musik und Synthetische Sprache’. This thesis defined the ongoing theoretical character of the studio as being based around electronically synthesised sound – in sharp contrast to Schaeffer’s musique concrète acoustic approach at GRN in Paris.

WDR Studio
WDR Studio showing 4 track tape recorder and a selection of patched wave generators and filters

WDR is seen as the ‘Mother of all Electronic Music Studios’ because it quickly became a meeting place and forum for an international group of avant-garde composers including Ernst Krenek (Austria/USA), György Ligeti (Hungary), Franco Evangelisti (Italy), Cornelius Cardew (England), Mauricio Kagel (Argentina) and Nam June Paik (Korea) and Gottfried Michael Koenig who became the technical assistant at WDR and helped many composers create their pieces as well as writing many key pieces of electronic music at WDR (Klangfiguren II (1955), Essay (1957) and Terminus I (1962)). The pioneering work of previous composers has been somewhat overshadowed by the arrival of Karlheinz Stockhausen at WDR (who succeeded Eimert as director in 1962) in 1953 with pieces such as ‘Gesang der Junglinge‘ and Kontakte (1960) and Hymnen (1967) which became landmark works within the electronic music oeuvre. 

Beat-frequency low frequency pulse generator
A low frequency pulse generator
Adjustable UBM feedback amplifier
Adjustable UBM feedback amplifier
A Heath sine and square wave generator
A Heath sine and square wave generator

The studio was originally equipped with a modified Trautonium by Dr Friedrich Trautwein modified to Meyer-Eppler’s specification called the Elektronische Monochord and  with a Melochord by Harald Bode  . As well as these instruments the studio consisted of:

  • Signal generators: sine , rectangular, sawtooth and noise
  • Filters: octave, third, radio drama (W49) filters.
  • Pulse generator
  • Ring Modulator
  • Oscilloscope
  • Rotary speaker for recording spatial sounds
  • Echo and reverb chambers: the reverb chamber being a large empty room where sounds could be played through speakers and re-recorded with the room ambience added.
  • Sixteen channel (2 X 8 channel) audio mixer
  • Patchbay to route modules
  • Tape Machines: several mono, 2-track and one 4-track (one of the earliest 4-track recorders made) tape recorders and a ‘Springer’ variable speed tape recorder with a rotating 6-fold playback head.
Later version Melochord
Later version Melochord at the WDR studio

The equipment of the studio was updated to Stockhausen’s specifications in early 1970s to include what by then was standard voltage controlled modular synthesisers, including a large customised EMS Synthi 100. WDR studio remained in use until  2000 when it was closed though some of the original equipment was saved from destruction and is now stored in the basement of the WDR building in Cologne, Germany.

EMS Synthi 100 vocoder custom built for WDR
EMS Synthi 100 vocoder custom built for WDR
Stockhausen by the custom Synthi 100 at the WDR Studio in the 1970s
Stockhausen by the custom Synthi 100 at the WDR Studio in the 1970s




Thom Holmes. Electronic and Experimental Music: Technology, Music, and Culture

Thomas B. Holmes. Electronic and Experimental Music: Pioneers in Technology and Composition

Der WDR als Kulturakteur. Anspruch – Erwartung – Wirklichkeit.  Published by the German Cultural
Council. Authors: Gabriele Schulz, Stefanie Ernst, Olaf Zimmermann. Berlin 12/2009. 464

‘Pattern Playback’, Franklin S. Cooper. USA, 1949

Franklin Cooper with the Pattern Playback machine

The Pattern Playback was not a musical instrument as such but an early hardware device designed to synthesise and analyse speech, designed and  built by Dr. Franklin S. Cooper and his colleagues, including John M. Borst and Caryl Haskins, at Haskins Laboratories in the late 1940s and completed in 1950.

Diagram showing the function of the Pattern Playback machine
Diagram showing the function of the Pattern Playback machine

The device converted a picture or ‘spectrogram’ of a sound back in to sound. The ‘Pattern Playback’ machine functioned in a very similar way to the Russian ANS Synthesiser using a photo-electrical system; a mercury arc-light was projected through a rotating glass disc printed with fifty harmonics of a fundamental frequency as a way of generating a range of tones. The light is then projected through an acetate ‘black and transparent’ spectrogram image that lets through the portions of light that carry frequencies corresponding to the spectrogram. The resulting ‘filtered’ light hits a photo-voltaic cell which generated the final audible sound .

The Pattern Playback machine
Pattern Playback
The Pattern Playback machine

Several versions of the device were built at Haskins Laboratories and used up until 1976. The Pattern Playback now resides in the Museum at Haskins Laboratories in New Haven, Connecticut.



The history of speech synthesis

The ‘Polychord’ Harald Bode, Germany, 1949

The Polychord II
Bode’s Polychord III 1951

The Polychord Organ was Harald Bode’s first postwar design commissioned by the Bayerischer Rundfunk, Southern German Radio as an electronic organ for live radio broadcasts and was often heard played by the popular organist Fekko von Ompteda and on occasions by Harald Bode himself.  The instrument remained in use at Bayerischer Rundfunk from 1950 until 1973 used for  in-house productions such as special effects, music for comedy shows, dance music and religious music.

Early version of the Polychord
Early version of the Polychord

The Polychord was a simpler, polyphonic version of the rather complex Melochord, re-designed with the professional organist in mind; offering a bank of preset sounds as well as free control of sound synthesis. Bode produced a second version, The Polychord III in 1951, produced and marketed by  Apparatwerk Bayern gmbh (ABW) company in Bavaria Germany, and the Bode Organ which became the prototype of the Estey Electronic Organ after his departure to the USA in 1954. The Bayerischer Rundfunk Polychord can be seen (2014) at the Musical Instruments collection at the Deutsches Museum von Meisterwerken der Naturwissenschaft und Technik in Munich, Germany.


Bode's notes for a prototype of the Polychord c 1949
Bode’s notes for a prototype of the Polychord c 1949
Bode's notes for a prototype of the Polychord c 1949
Bode’s notes for a prototype of the Polychord c 1949



Bode’s Melodium and Melochord by Thomas L. Rhea. Contemporary Keyboard magazine (January 1980)


The ‘Baldwin Organ’ Winston E. Kock & J.F. Jordan, USA, 1946

Early Model of Winston Kock's Baldwin organ
Winston Kock’s Baldwin Organ Model Five 1947

The Baldwin organ was an electronic organ, many models of which have been manufactured by the Baldwin Piano & Organ Co. since 1946. The original models were designed by Dr Winston E. Kock who became the company’s director of electronic research after his return from his studies at the Heinrich-Hertz-Institute, Berlin, in 1936. The organ was a development of Kock’s Berlin research with the GrosstonOrgel using the same neon-gas discharge tubes to create a stable, affordable polyphonic instrument. The Baldwin Organ were based on an early type of subtractive synthesis; the neon discharge tubes generating a rough sawtooth wave rich in harmonics which was then modified by formant filters to the desired tone.

Tone modifying circuits of the Baldwin organ
Tone modifying circuits of the Baldwin organ

Another innovative aspect of the Baldwin Organ was the touch sensitive keyboard designed to create a realistic variable note attack similar to a pipe organ. As the key was depressed, a curved metal strip progressively shorted out a carbon resistance element to provide a gradual rather than sudden attack (and decay) to the sound.  This feature was unique at that time, and it endowed the Baldwin instrument with an unusually elegant sound which captivated many musicians of the day.

“How did it sound? I have played Baldwin organs at a time when they were still marketed and in my opinion, for what it is worth, they were pretty good in relative terms.  That is to say, they sounded significantly better on the whole than the general run of analogue organs by other manufacturers, and they were only beaten by a few custom built instruments in which cost was not a factor.  It would not be true to say they sounded as good as a good digital organ today, but they compared favourably with the early Allen digitals in the 1970’s.  Nor, of course, did they sound indistinguishable from a pipe organ, but that is true for all pipeless organs.  To my ears they also sounded much better and more natural than the cloying tone of the more expensive Compton Electrone which, like the Hammond, also relied on attempts at additive synthesis with insufficient numbers of harmonics.”

From ‘Winston Kock and the Baldwin Organ; by Colin Pykett

Electronic Generator of the earlt model Baldwin Organ
Electronic Tone Generator of the early model Baldwin Organ showing neon gas-discharge tube oscillators.

Kock’s 1938 Patent of the Baldwin organ

Winston Kock playing an early experimental design for an electric instrument
Winston Kock playing his early experimental electronic instrument 1932

Winston E. Kock Biographical Details:

Winston Kock was born into a German-American family in 1909 in Cincinnati, Ohio. Despite being a gifted musician he decided to study electrical engineering at Cincinnati university and in his 20’s designed a highly innovative, fully electronic organ for his master’s degree.

The major problem of instrument design during the 1920’s and 30’s was the stability and cost of analogue oscillators. Most commercial organ ventures had failed for this reason; a good example being  Givelet & Coupleux’s  huge valve Organ in 1930. it was this reason that Laurens Hammond (and many others) decided on Tone-Wheel technology for his Hammond Organs despite the inferior audio fidelity.

Kock had decided early on to investigate the possibility of producing a commercially viable instrument that was able to produce the complexity of tone possible from vacuum tubes. With this in mind, Kock hit upon the idea of using much cheaper neon ‘gas discharge’ tubes as oscillators stabilised with resonant circuits. This allowed him to design an affordable, stable and versatile organ.

Kock's Sonar device during WW2
Kock’s Sonar device during WW2

In the 1930’s Kock, fluent in German, went to Berlin to study On an exchange fellowship (curiously, the exchange was with Sigismund von Braun, Wernher von Braun’s eldest brother –Kock was to collaborate with Wernher twenty five years later at NASA) at the Heinrich Hertz Institute conducting research for a doctorate under Professor K W Wagner. At the time Berlin, and specifically the Heinrich Hertz Institute, was the global centre of electronic music research. Fellow students and professors included; Jörg Mager, Oskar Vierling, Fritz Sennheiser, Bruno Helberger, Harald Bode, Friedrich Trautwein, Oskar Sala and Wolja Saraga amongst others. Kock’s study was based around two areas: – improving the understanding of glow discharge (neon) oscillators, and developing realistic organ tones using specially designed filter circuits. 

Kock worked closely with Oskar Vierling for his Phd and co-designed the GrosstonOrgel in 1934 but disillusioned by the appropriation of his work by the newly ascendant Nazi party he decided to leave for India, sponsored by the Baldwin Organ Company arriving at the Indian Institute of Music in Bangalore in 1935.

Returning from India in 1936, Dr Kock became Baldwin’s Director of Research while still in his mid-twenties, and with J F Jordan designed many aspects of their first electronic organ system which was patented in 1941.

Winston E Kock (L) as the first Director of Engineering Research at NASA

When the USA entered the second world war Kock moved to Bell Telephone Laboratories where he was involved on radar research and specifically microwave antennas. In the mid-1950’s he took a senior position in the Bendix Corporation which was active in underwater defence technology. He moved again to become NASA’s first Director of Engineering Research, returning to Bendix in 1966 where he remained until 1971 when he became Acting Director of the Hermann Schneider Laboratory of the University of Cincinatti. Kock Died in Cincinatti in 1982.

 Winston Kock was a prolific writer of scientific books but he also wrote fiction novels under the pen name of Wayne Kirk.

Acoustic lenses developed by Winston Kock at the Bell Labs in the 1950's
Acoustic lenses developed by Winston Kock at the Bell Labs in the 1950’s
Acoustic lenses developed by Winston Kock at the Bell Labs in the 1950's
Acoustic lenses developed by Winston Kock at the Bell Labs in the 1950’s
Acoustic lenses developed by Winston Kock at the Bell Labs in the 1950’s


Hugh Davies. The New Grove Dictionary of Music and Musicians


The ‘Mastersonic Organ’ John Goodell & Ellsworth Swedien, USA, 1949

The Mastersonic Organ was an improved tone wheel organ designed to produce more accurate pipe organ sounds. The designers,  John Goodell and Ellsworth Swedien, discovered that if they shaped the tone-wheel ‘pickups’ they could induce tones with different ‘natural’ harmonic content – rather than attempt to create a pure sine wave and artificially colour it as in the Hammond Organ. To achieve this the Mastersonic had individually shaped magnets for each tone wheel sound; a “string” magnet, a “flute” magnet, a “diapason” magnet, and so on.

Mastersonic Tone Generation
Mastersonic Tone Generation (Alan Conway Ashton ‘electronics, Music and Computers’ 1971)

“…There were twelve shafts with seven pitch wheels each which rotated near the irregularly shaped magnets wound with coils. Each of the pitch wheels contained twice as many rec­tangular teeth as the preceding one, so seven octaves were produced per shaft. Several differently shaped poles were dispersed radially around each wheel.”
Alan Conway Ashton electronics, Music and Computers

Each tone-wheel was shielded against magnetic interference from the other, adding to the bulk and complexity of the instrument. The instrument was controlled by a seven octave special keyboard, designed to simulate attack envelopes. The resulting sound was indeed a much more accurate pipe organ sound but at the expense of size; the Mastersonic was a huge, complex and expensive machine and few were built or sold.


‘Microsound’ Curtis Roads MIT 2001

ELECTRONICS, MUSIC AND COMPUTERS. Alan Conway Ashton. December 1971 UTEC-CSc-71-117

The ‘Emiriton’ A. Ivanov, V.A. Kreytser & Andrey Rimsky-Korsakov, Russia, 1943

Late 1950's version of the Emiriton
Late 1950’s version of the Emiriton

The Emiriton was an example of a series of finger-board electronic instruments developed in the Soviet Union in the 1930’s, inspired perhaps by Leon Termen’s avoidance of a standard keyboard with his Theremin. Other instruments included V.A.Gurov’s (a former colleague of Leon Termen) “Neo-Violena“(1927) the “Sonar“(1930) and the Volodin’s “Ekvodin” (1931). Designed by A. Ivanov and A.Rimsky-Korsakov, The Emiriton was a originally a fingerboard instrument allowing the use of glissando effects, with later models incorporating a standard keyboard. The Emiriton generated sound from neon-tube oscillators and was able to replicate sounds such  as  the bassoon, violin, cello and clarinet.

Rimsky Korsakov
Andrey Vladimirovich Rimsky-Korsakov

Biographical Information: Andrey Vladimirovich Rimsky-Korsakov

Andrey Vladimirovich Rimsky-Korsakov, grandson of the famous Russian composer,studied at the Leningrad Conservatory and the Leningrad Polytechnical Institute. His combination of musical and technical knowledge allowed Andrey Vladimirovich to work successfully at the Research Institute of Musical Industry organized by Academician N.N.Andreyev. From 1932 he collaborated with the engineer A.A.Ivanov to construct one of the earliest Russian electric musical instruments: the Emiriton. In early 1941, Rimsky-Korsakov moved to the Leningrad Physicotechnical Institute of the Academy of Sciences of the USSR, where he began his investigations in hydroacoustics. In 1942, he joined the Navy and, during the war was involved in designing and testing acoustic mines. After the war, Rimsky-Korsakov returned to his studies in musical acoustics at the Leningrad Electrotechnical Institute of Communication, and later at the Acoustics Institute of the Academy of Sciences of the USSR, Moscow. In 1960, Rimsky-Korsakov established the Department of Electroacoustics and Ultrasonics at the Moscow Mining Institute focussing on acoustical measurements, and noise and vibration control and technological processes of low-frequency acoustic vibrations.


Time, Volume 44. 1944

Music of the Repressed Russian Avant-garde, 1900-1929 By Larry Sitsky

Soviet Physics: Acoustics, Volume 36

Chamberlin ‘Rhythmate’, Harry Chamberlin, USA,1947

Chamberlin Rhythmate
Chamberlin Rhythmate

Created in 1949, The ‘ Rhythmate’ was one of the first electronic drum machines ever produced. The instrument was designed and built (probably only ten machines were ever produced) by Harry Chamberlin in Upland, California. With the success of the Chamberlin keyboards in the 1960s Harry Chamberlin updated the drum machine – the Rhythmate model25/35/45 produced from 1960-1969 with 100 models sold.

Chamberlin Rhythmate
Control panel of the Chamberlin Rhythmate 1960’s model

The Rhythmate was a tape loop based drum machine designed to accompany an organ player. the instrument had 14 tape loops with a sliding head that allowed playback of different tracks on each piece of tape, or a blending between them. It contained a volume and a pitch/speed control and also had a separate amplifier with bass, treble, and volume controls, and an input jack for a guitar, microphone or other instrument. The tape loops were of real acoustic jazz drum kits playing different style beats, with some additions to tracks such as bongos, clave, castanets, etc. The Rhythmate has a built-in amplifier and 12″ speaker.

In 1951, Harry Chamberlin used his idea of magnetic tape playback to create the Chamberlin Model 200 keyboard. The Model 300/350, 400, 500 and 600/660 models followed.

Chamberlin Rhythmate
Inside the Chamberlin Rhythmate showing amplifier 10″ speaker and tape loops