The ‘Syn-ket’ (or ‘Synthesiser-Ketoff’). Paolo Ketoff & John Eaton, Italy. 1963.

The Syn-Ket
Paul Ketoff’s  ‘Syn-Ket’ c 1965

With the debut of affordable transistors in the late 1950s, several electronic engineers, inspired by the ideas of Harald Bode, realised the potential for creating lightweight, affordable and durable electronic instruments. Bode’s proposal for voltage controlled transistor based instruments ( “European Electronic Music Instrument Design”, Journal of the Audio Engineering Society (JAES) ix (1961): 267) inspired Robert Moog, Donald Buchla and Paul Ketoff amongst others to put Bode’s ideas into practice.

Paul Ketoff (L) and John Eaton (R) demonstrating the Syn-Ket. Rome, circa 1963

Paul Ketoff was an American- Polish-Italian sound engineer working for RCA based at the Cinecittà film studios in Rome. In the summer of 1956, Ketoff was invited by the composers Otto Leuning and George Balch Wilson to design a new electronic music studio at the American Academy in Rome– Otto Leuning was the composer in residence at the Academy and organised finance for the project via Columbia Princeton’s Alice M. Ditson fund.

Ketoff built a tape-based studio in the basement of the Academy at Via Angelo Masina (comprising of: three sine wave oscillators, a spring reverberation unit, a microphone, an Ampex stereo portable tape recorder,a mixing console, 350 Series Ampex mono tape recorder and a radio/record player) and then went on to develop the ‘Fonosynth’ in 1958; a large studio synthesiser with musical direction from Leuning, Gino Marinuzzi jr and other composers at the academy.

“But, Paul.  This is not just a group of components of a classical tape studio; this is an instrument!”

John Eaton 1963 – Interview  2012

Inspired by Harald Bode‘s ideas proposed in the 1961 JAES Journal, Paul Ketoff designed a new, much smaller, voltage controlled transistor based synthesiser to replace the Fonosynth (and again, indirectly funded by Colombia Princeton). Ketoff presented his new instrument christened the ‘Syn–Ket’ (Synthesiser-Ketoff) to the American composer John Eaton at the American Academy, who quickly recognised the possibilities of using the synthesiser for live performances; that is, performances without any tape recorders – electronic music performances of that period usually relied on recorded sound because ‘synthesisers’ were huge, stationary, multi component, studio based devices and far too big to move to a live performance space.

“I immediately began writing short pieces that could be played on it, without any pre-recording and asked him to build me one that could be modified for better use as an instrument.  At my suggestion, he modified the three keyboards so they would respond to velocity, like a piano, and sideways motion, as in a clavichord’s bisbigliando.  Over the next few years, he added an overall volume pedal, a white or pink noise generator, alternate basic sonic material, a spring reverberation unit, and other various types of modulation. “

John Eaton – Interview  2012

Paul Ketoff (right) and John Eaton (playing) performing with the Syn-Ket in Italy, 1963.
The Synket at the Philharmonie de Paris (musical instrument museum). Image ©Philharmonie de Paris
The Synket at the Philharmonie de Paris (musical instrument museum). Image ©Philharmonie de Paris

The Syn-ket comprised of three sound modules or “sound-combiner” as Ketoff called them – essentially three separate synthesisers built using a mix of solid state and vacuum  technology. Each module was independently controllable and interconnectable and mixable into a single output.

Each “sound-combiner” module consisted of:

  • 1 square wave frequency-controllable oscillator.
  • A button controlled series of frequency dividers which allowed division of the incoming  pitch by factors of 2, 3, 4,  5 and 8 to produce differing harmonics
  • 3 complex filters with a frequency range of 40 Hz – 20 kHz.
  • 1 amplitude control.
  • 3 modulators each controlled by a low frequency oscillator: The first allowed control of the square wave oscillator’s frequency, The second controlled the frequency of the filter and the third controlled audio amplitude.

Later versions were equipped with white and pink noise generators and a spring reverberation unit.

The Syn-ket was equipped with three small two octave keyboards, each corresponding to a module. Each key could be individually tuned allowing the musician to play and compose microtonal music. The keyboard was velocity sensitive and uniquely allowed the player to bend the note with a sideways finger action. The second version of the Synket allowed the player to control amplitude and filters through key velocity.

the art of electronic music_0002
Ketoff and Eaton with the Syn-Ket 1963 (image copyright ‘the art of electronic music’)

The Syn-ket was adopted by John Eaton as his concert instrument and he made over a thousand performances from 1966 to 1974 and used the Syn-ket in several of his recorded compositions, such as “Piece concert is Synket and Symphony Orchestra” (1967), “Blind Mans Cry” (1960), “Mass” (1970).

The Syn–ket was not conceived as a commercial product – Ketoff built only about a dozen variations on the Syn-ket theme  between 1963 and 1977 – and notwithstanding it’s innovative and unique features remained a one-off custom made instrument. Despite this, the Syn-ket was widely used by composers other than Eaton and found itself almost ubiquitous on Cinecittà soundtracks for Spaghetti westerns (Ennio Morricone used the Syn-ket on many of his soundtrack scores ), Italian horror and science fiction films.

One of the few surviving Syn-kets can be seen at the Philharmonie de Paris (previously know as the ‘musical instrument museum’) Paris, France.

Images of the Syn-ket

Eaton went on to collaborate with Bob Moog on an a controller keyboard called the ‘Eaton-Moog Multiple-Touch-Sensitive Keyboard’. Moog and Eaton had initially met when Eaton asked Moog to repair an ailing Syn-ket during a 1966 US tour. They immediately began collaborating on a new keyboard controller based on Ketoff’s triple keyboard of the Syn-ket. The final controller was straightforwardly named the ‘Eaton-Moog Multiple-Touch-Sensitive Keyboard’ or ‘MTS’

John Eaton playing the Syn-ket

Biographical Notes Paul Ketoff/Paolo Ketoff.

Polish-Italian Electronic and sound engineer. Born 1921 died 1996. Ketoff became the chief sound technician at RCA Italiana/Cinecittà film studios, Roma, in 1964 and the Fonolux post production company, between 1957 and 1965. Ketoff designed many devices for film music production including dynamic sound compressors and ring modulators, reverb chambers and plates, and established a new standard of sound post-production.

Film credits for sound production and effects from this period include (1966) ‘Africa Adido” , (1966) ‘La Traviata’ (1965) ‘Terrore Nello Spazio’, (1960) ‘L’ avventura’ (1953) ‘Pane, amore e fantasia’ (1965) ‘Planet of the Vampires’, (1959) ‘Hercules Unchained’

Commisioned to design and build the Electronic Music Studio at the American Academy in Rome, Ketoff finished his first synthesiser, the ‘Fonosynth’ in 1958 and then designed a much more compact voltage controlled performance instrument called the Syn-ket in 1963 which was presented at the conference of the Audio Engineering Society (AES) in 1964,

Ketoff was a lifelong friend and collaborator with the Italian composer Gino Marinuzzi jr. Paolo Ketoff was married to Landa Ketoff, the well known musical critic for La Repubblica Newspaper.

John Eaton

John Eaton Biographical Notes:

Born: March 30, 1935 in Bryn Mawr (Pennsylvania, USA)
The composer John Eaton began his musical career as a child, taking piano lessons at the age of nine and his first concert, playing Beethoven sonatas. In 1957, at age 22.
Eaton graduated in Princeton University. In 1959 he moved to Rome (Italy) and lived there in the following years. There he began a long time partnership with clarinetist Bill Smith – Their band recorded two albums and made several concerts in Europe and in the United States. In Rome John Eaton met the electronic engineer Paul Ketoff, inventor of the famous and legendary Syn-Ket, in 1964. With the Syn-Ket, John Eaton performed more than a thousand concerts around the world. Eaton later collaborated with Robert Moog to develop the ‘Eaton-Moog Multiple-Touch Sensitive Keyboard’.


 “The Synthesizer.” Vail, Mark.

Interview with John Eaton:

Electronic Music Review. No. 4 October 1967

Interview with John Eaton NAMM.  January 23, 2010.

‘Electronic Music’ By Nick Collins, Margaret Schedel, Scott Wilson

‘Electronic and Computer Music’ Peter Manning. Oxford University Press p130

A History of the Rome Prize in Music Composition * 1947 – 2006 * Richard Trythall .Music Liaison. American Academy in Rome January 1, 2007

‘Music and Musical Composition at the American Academy in Rome’. Martin Brody. University of Rochester Press. 2014.

‘In The Workshop’. John Eaton.

4 thoughts on “The ‘Syn-ket’ (or ‘Synthesiser-Ketoff’). Paolo Ketoff & John Eaton, Italy. 1963.”

  1. The photo above which is labeled “Paul Ketoff playing the Syn-ket” is in fact MIS-labeled. It shows JOHN EATON (without beard) “playing the Syn-Ket” – Paul Ketoff. Please correct. (I was his student at Indiana University in the 1970s.)

  2. Dear Simon,
    Again, congrats on such an amazing website…my students and I refer to it often. Sadly, you may update John Eaton’s dates on this page to “died December 2, 2015.” We have a Syn-ket at Indiana University where John taught and are looking into restoring it. Alas, its three-tiered keyboard was sent to Italy during John’s life for repair and never returned, current whereabouts unknown.

    Best, Jeffrey Hass, Director, Indiana University Center for Electronic and Computer Music

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