Minimoog Model D: the first synthesizer sold in shops

A modular Moog cut down to one cabinet

In the 1960s the Moog modular synthesizer was a room-sized proposition: separate modules joined by patch cables, sensitive to temperature and humidity, and priced in the tens of thousands of dollars. Most systems belonged to universities and record labels, and by 1970 only 28 were owned by musicians.

Company engineers built a smaller instrument on their own initiative. The first prototype, the Min A, was a keyboard sawn in half and wired to unused modular parts in a small cabinet; the Model B and Model C prototypes added expression, simplicity and portability. When the company began losing money in early 1970, the engineers finished the Model D — and the firm, which had at first seen no market for it, put it into production. The team expected to sell perhaps 100 of them.

The Minimoog was conceived as a portable tool for session musicians, and it became the first synthesizer sold in ordinary music shops. Demand outran what the small company could finance, and in November 1971 it was sold to a rival firm. The Model D stayed in continuous production for 13 years; more than 12,000 were made before production stopped in July 1981.

The panel, left to right

Everything a modular player would patch by hand is wired inside the Minimoog, in a fixed order that runs across the front panel. Learning it means learning the basic signal path of almost every analog synthesizer since: oscillators, mixer, filter, amplifier.

Why it sounds the way it does

Two accidents of engineering shaped the Minimoog's voice. Its builders could not fully stabilise the power supply, so the three oscillators were never completely synchronised: they drift against each other just enough to sound warm and rich rather than static. And its voltage-controlled filter — the four-pole "ladder" design inherited from the modular systems — can turn the same raw waveform into anything from a punchy funk bass to a soft, high lead.

It plays one note at a time (monophonic) and one sound at a time (monotimbral). With low-note priority, the lowest held key wins: hold a note and tap a higher one, and the pitch does not change. Players use this for trills and quick bass figures, but it surprises anyone who expects the most recent key to sound, as on many later synthesizers.

Reissues, successors and look-alikes

After the original company changed hands and later closed, the Moog name was split for years between the United States and the United Kingdom, which is why the later models have a tangled history. The main ones are listed below.

The Voyager came in several versions: a rack-mount edition (2005) designed to be played over MIDI, the Old School (2008–2009) with no software or MIDI but with keyboard pitch and gate outputs, and the XL (2010), with a 61-note keyboard, a ribbon controller and a patch bay. Moog Music also released a Minimoog Model D app for iOS in 2018, and other makers have produced compact instruments modelled on the original.

Using a Minimoog on a session

1. Write the sound down. An original Model D cannot store anything. Photograph the panel or note every knob and switch before you move on; a Voyager or reissue can save patches.
2. Plan chords as overdubs. It plays one note at a time, so harmonies are built take by take, often with small tuning differences that add width.
3. Let it warm up and retune. Free-running analog oscillators move as the circuits and the room warm. Tune against a reference after it has been on for a while, and again between long takes.
4. Check the control standard. Originals have no MIDI. To play one from a sequencer you need a MIDI-to-CV/gate converter that matches its control voltage and trigger. The session checklist covers the questions to ask.
5. Mind the priority. Because of low-note priority, overlapping legato notes behave differently from a modern synth; play the line as you want it to sound rather than relying on note order.