Moog Polymoog Synthesizer - an auralesque miracle

Polymoog? No, no, no .. out of the question … never-ever! That’s what I thought for years. Until Uncle Sigi called in 2024. He had fulfilled a late childhood dream and bought the Polymoog, but there was hardly any time for the instrument in everyday life, so the Polymoog was rarely played. Perhaps the synthesizer would be in better hands with me? Magically attracted by the prospect of a fully polyphonic vintage synthesizer with 71 keys (!), I couldn’t resist the request …

Uncle Sigi himself got the Polymoog from a collector (and technician) not entirely unknown among insiders, who had several examples and whose spontaneous response to my service request was “If there’s anything – sure, bring it over!”. Remarkable, because almost all synthesizer technicians in central Europe refuse to put this synthesizer on their workbench today. “Polymoog? No no no … out of the question, never ever!”

After a few weeks of blissful testing – I didn’t commit to the purchase immediately, but asked for a period of reflection and exploration – the Polymoog stopped sounding. Just like that. Power – all there, LEDs – light up, hum in the audio signal … but … no sound. So I contacted the technician in question, drove more than 500 kilometers to Rheinland-Pfalz (Germany) in a somewhat gloomy mood (and with a damaged Polymoog in my luggage) … and hoped for a miracle.

The miracle occured. The technician opened the Polymoog, measured the power supply, checked the 3 circuit boards on the top, located the fault area, replaced a tantalum on suspicion … and, well, the synthesizer was back to life! The repair took 3 minutes. I was impressed (by the technician) and disappointed (considering the 500 kilometer drive for such a small repair, though a service for the LEDs and the keyboard followed on the same day).

Contact with Uncle Sigi – the instrument has been fixed – and consultation with the technician as to whether I could come by in future for any Polymoog troubles (“Sure, bring it along!”), since good service is half the battle with the Polymoog. So: “Thumbs Up!” – the instrument was finally purchased in spring 2025! Since then, the Polymoog has been enhancing the studio with unearthly pads and aural soundscapes that are second to none …

The Constellation Synthesizer Ensemble Project

The Polymoog was originally part of a larger instrument system that Moog planned to launch in 1974: The Constellation Synthesizer Ensemble. Consisting of several parts, the system would have been made up of the solo synthesizer LYRA (developer: Bob Moog, Jim Scott), the poly synthesizer APOLLO (developer: David Luce) and the foot pedal bass synthesizer TAURUS.

According to synth literature, a single example of the LYRA – the first Moog synthesizer with velocity response – was built (perfectcircuit.com, however, mentions several units in its article) and used by Keith Emerson in the following years. Two APOLLO synthesizers saw the light of day before David Luce completely revised the concept and it became the Polymoog. Only the TAURUS – albeit in a heavily modified form – finally went into series production.

Apollo becomes Polymoog

Launched in 1975, the Polymoog must have initially seemed like an instrument from distant galaxies: full polyphony, 71 keys, presets – it sounded like science fiction. For several years, the Polymoog – alongside Oberheim’s Four-Voice / Eight-Voice – was the top dog in the polyphonic synth sector. It wasn’t until 1977 that the Yamaha CS series, the Korg PS series and, a year later, the Sequential Prophet-5 and Roland Jupiter-4 provided much-needed new additions to the polyphonic synthesizer range.

Don’t get bored with the history of the Polymoog. I myself was 3 years old at the time of its release (no personal experience to speak of), and the synthesizer literature is full to the brim with anecdotes about the Polymoog. One thing is certain: The rapid rise was followed by a long fall. The frequency divider circuits (“It’s not a real synthesizer”), technical unreliability and especially the sensitivity during transport were points of criticism surrounding the Polymoog, whose production ended in 1980.

At least two aspects are noteworthy: The development of the Polymoog (then known as the Apollo) began in 1972, soon after the Minimoog was released. In addition, the new synthesizer was developed by an acoustics expert, Dr. David Luce. This may explain the “musical background” of the device, because like hardly any other polyphonic synthesizer, the Polymoog is a player’s instrument that shines with unusual musical details …

Design of the Polymoog Synthesizer (Model 203A)

The sound generation is based on two groups of master oscillators (sawtooth and pulse wave), which are responsible for the sound per key via frequency dividers. So that each of the (maximum) 71 voices can have its own filtering or its own dynamic progression – this was the decisive further development compared to the paraphonic Apollo – a separate, palm-sized chip was developed, which is responsible for shaping the sound of each key.

The two basic waveforms sawtooth and pulse can be fed individually or mixed to the LOWER / UPPER or the entire keyboard, with foot positions from 16′ (pulse) to 4′ (sawtooth). The FINE TUNE control on the far left can be used to adjust the overall pitch, while the integrated BEAT control allows the basic waveforms to be detuned from each other for the purpose of adjusting and metering beats.

In order to achieve bass-mid-treble adjustments via the 71-key keyboard, the octaves 1/2, 3/4 and 5/6 can be individually adjusted in volume. A small barrier has been built in here to prevent the volumes from dropping completely, as polymoogs that initially worked perfectly were sent back as broken after customers had accidentally set all the OCTAVE BAL(ance) controls to “0” and therefore no sound could be heard.

Next on the panel: RANK TUNE allows the sawtooth wave to be offset by approximately a seventh (+/-) in relation to the pulse wave to give the orchestral sound of the Polymoog a extra pinch of cinemascope or fanfare character … provided that the interval is precisely set (this is where the BEAT control comes into play again, e.g. to be able to set a pure fourth or a pure fifth exactly, which is quite difficult using the RANK TUNE slider alone).

Sawtooth / pulse can each be frequency-modulated using their own (!) LFO and the pulse wave or PW modulation (again with its own LFO) can be controlled separately for LOWER / UPPER. Finally, the mixing ratio of the sawtooth sound component (to the pulse wave) can also be set separately for LOWER / UPPER using RANK MIX. All these subtleties relating to frequencies, volumes, mixing ratios and modulation intensities result in a liveliness that makes the Polymoog unique.

However, this uniqueness is not necessarily perceptible in the 8 presets. They are simple sounds that David Luce called MODES, as they do not represent “absolute” sound ideas, but rather embody the “relative” character of a certain type of instrument (PIANO, VIBES, BRASS …). In addition, the MODES are tuned to the velocity-sensitive (!) 71-key keyboard so that pianists/organists can easily play the piano/organ literature they are familiar with on the Polymoog (or so the idea goes).

You can hear these presets / modes in the attached sound samples. Not spectacular and even with small electronic dropouts here and there (we left it at this “acoustic reality” on the day of recording), but they are “ok” and quite usable as a basis for your own sounds. Number 9 – VAR(iable), the “free” mode – is of course of overriding interest to the sound tinkerer, that’s where you want to go! The LOUDNESS CONTOUR section plays a central role in the free programming of the Polymoog …

… where the keyboard dynamics (on attack, timbre/filter and volume) as well as the global attack, decay and decay time (for UPPER / LOWER separately) can be set. The parameters interact with each other, of course also in connection with sustain, which may present a small challenge for the typical synthesizer player / programmer, but at the same time can also be a source of unexpected – because unwanted – sound progressions (dynamics!).

Following the panel further to the right there are two more sections that have a global effect on the sound of the Polymoog. The RESONATORS – well known from Kraftwerk and other groups that used this module – are a static triple filter (switchable LOWpass / BANDpass / HIGHpass), which can be adjusted in the LOW / MED(ium) / HIGH ranges in terms of frequency, resonance and volume and essentially provides quite unusual timbres.

The final VOLTAGE CONTROLLED FILTER is a classic 24dB cascade filter with cutoff and resonance, as well as its own LFO (including sample & hold) and its own envelope (ADS). This Moog filter exists once and turns the Polymoog into a paraphonic-sounding instrument when played with multiple voices, as the filter restarts automatically each time a key is pressed. Keith Emerson vehemently criticized this behaviour in the predecessor Apollo, which ultimately led to the revision of the instrument, the development of the synthesizer chip (one per key) and thus to the creation of the Polymoog.

Back to the single Moog filter. Since all sound sections of the Polymoog can be mixed (the paraphonic sound component can therefore be easily “masked”), and the synthesizer can of course also be used for solo sounds, the single filter module is of great benefit in any case. It is also worth noting at this point that both the RESONATORS and the VOLTAGE CONTROLLED FILTER have their own audio input, meaning that these modules can be used completely independently to process external sound sources.

Which brings the connections to the center of attention. Via POLYPEDAL (Model 285, optional accessory), a massive foot controller can be used to control pitch, volume, filter frequency, sustain and other parameters. In addition, a monophonic synthesizer can be controlled from the Polymoog (including keyboard scale control – very convenient), which means that, for example, a Minimoog placed on the large plastic lid can be controlled over a full 6 octaves.

The audio signal from the Minimoog could now be fed to the AUX (In) socket and controlled as a separate sound source on the Polymoog’s mixer panel – including the glide function, which is specially designed for the external synthesizer with its own control. Massive Polymoog pads and the equally massive lead or bass voice of a Minimoog, all controlled from a central location – that does indeed sound tempting for a live musician.

Sound and more …

The true gold of the Polymoog lies in its numerous signal paths with 6 (!) audio outputs. MIX Balanced/Unbalanced, MODE, VCF, DIRECT and RES(onators) – everything can be mixed individually on the panel and tapped separately. If you then subject the individual signals to a simple right/left adjustment on the mixing console, including equalizing and adding effects (we mainly opted for phaser and delay), you get as close as possible to auralesque sound heaven.

Polyphonic pads can become room-filling sound wonders, as can be heard in the majority of the attached sound examples – apologies at this point for the one-sided sound presentation of the Polymoog. But what can we say? This massive (and yet pleasantly warm, always musical sounding!) polyphony is unique, no synthesizer can compete with the Polymoog here. A positive side effect of the lively, organic overall sound is also the Polymoog’s good integration capability in the mix.

Above all, the 71-key keyboard (Pratt & Read) should be mentioned, which is surprisingly grippy under the fingers and extremely pleasant to play (more pleasant than many a made-in-China or made-in-Italy keyboard in 2025). The Polymoog keyboard requires a little servicing from time to time, but the mechanics are basically reliable and both the wide range of 71 keys and the touch dynamics contribute significantly to the orchestral sound of the instrument.

Finally, the Polymoog’s user-friendly panel should be mentioned as a sound design feature. As the 95 knobs and switches (including the ribbon controller) are easy to reach while playing, sound changes can be made ad hoc, even with full chords. The very long release times naturally contribute significantly to the fact that extensive adjustments can be made to the sound while making music without having to interrupt the creative flow. Long textures are created, Klaus Schulze sends his regards!

The multiple LFOs (for sawtooth/pulse frequency modulation, PWM and filter modulation), the sometimes beguiling (vocal) filter possibilities of the resonators, the comprehensive fine and interval tuning options … Details that are undoubtedly the work of Dr. David Luce, who is dedicated to the laws of acoustics.

But not only technical refinements, but also technical shortcomings contribute to enhancing the Polymoog’s character. One of the main problems (if you want to call it that) are the 71 sound shaping cards (each chip with envelope, double VCA and 12dB filter), well hidden inside the Polymoog. It is not uncommon for one or other of the socketed cards to make poor contact, resulting in a completely different sound – no dynamic control – for the key in question.

What was one of the main problems for musicians in the 1970s – the unreliability of the chip contacts, every transport of the Polymoog was a risk – can now be seen as a valuable source of an even livelier sound. Individual tones (those where the corresponding card is not correctly inserted in the socket) sound louder, unfiltered, possibly disturbing … at any rate not beautiful (the dynamic shaping is missing), but at the same time interestingly different in the mixture of the fully polyphonic overall sound (since – as already mentioned – it only affects individual notes / keys).

At this point, it should also be added that the chip contact problem in question is easy to solve: Open the Polymoog (loosen 2 + 4 screws, lift off the light plastic cover), open the 3 top boards with hinges (loosen a few screws) and all 71 sound cards are accessible. Now push in the cards with poor contact and the problem should be solved. From the studio musician’s point of view this is a simple matter, but from the live musician’s point of view it is a major handicap that contributed significantly to the unpopularity of the instrument in the 70s / 80s.

All in all

The Polymoog synthesizer (Model 203A) should – not surprisingly – appeal primarily to those keyboardists who have a penchant for lively vintage sounds (velocity response), room-filling pads (full polyphony) and open, wide frequency ranges (6-octave keyboard). It could, we dare say, even be a dream synthesizer for this target group. In any case, it appeals to live musicians who have sufficient playing skills and like to “hit the keys”.

Synthesizer nerds and sound tinkerers, on the other hand, may be bothered by the rather limited architecture of the Polymoog. There are only a few modulation options, unconventional envelopes, no sync, no ring and cross modulation, no noise. Not to mention the Polymoog’s almost non-existent (external) control/trigger options … and even thinking about a commercially available MIDI retrofit is as good as forbidden, because it doesn’t seem to exist.

What is certain is that the Polymoog – whether as a synthesizer (Model 203A) or in the reduced version as a preset keyboard (Model 280A) – has influenced entire generations of musicians. ABBA, Tony Banks, Michael Boddicker, John Bowen, Walter/Wendy Carlos, Chick Corea, Keith Emerson, Kraftwerk, Mike Oldfield Band, Herbie Hancock, Larry Fast, Jon Lord, Patrick Moraz, Gary Numan, Billy Preston, Saga, Klaus Schulze, Tomita, Rick Wakeman, Steve Winwood, Stevie Wonder … and many more (Sources: Peter Forrest; The A-Z of Analogue Synthesisers, Part One: A-M, revised, page 280; Polymoog Owner’s Manual, page 36).

It is also clear that the instrument is not only famous for its full polyphony / pad sounds, but is also notorious for its service requirements. Since hardly any technician is willing to take on the Polymoog these days, this could be the most delicate point when weighing up whether or not it would be a good move to buy this synthesizer. In any case, the Polymoog can be found regularly on the second-hand market, with prices currently ranging from 4,000 euros (private) to 8,000 euros (Reverb & Co.).

What the Polymoog can do musically can be heard in the following 50+ minutes of audio files. As already indicated, our sound variety leaves something to be desired (we apologize), because the majority of the demos – apart from some bass and solo sounds – are characterized by pads and other polyphonic structures, for which the Polymoog – nomen est omen – is wonderfully suited. Further demos of the Polymoog can be found on YouTube and in the recordings of many musicians / bands from the late 70s and early 80s.

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PS: The word auralesque doesn’t really exist (apart from a Swiss synthesizer project from the 90s). Nevertheless, we find it appropriate in this context, because it expresses onomatopoeically what we think the Polymoog sounds like: airy, light, lively, magical!

But the Polymoog can also sound completely different. When using the resonators, its character can be overdriven, aggressive, untamed and wild (thanks to a friend who commented about those myriads of rock musicians who certainly preferred the more radical part of the Polymoog sound).
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