The Birth of Moog Theremins, 1953-1956

For more than a century, the theremin has remained a steady and musically rich presence in the pantheon of electronic music. Although the field of has been broadened by tributes and variants built by other inspired makers, it has nonetheless been dominated by only two gifted individuals; Leon Theremin, whom Bob Moog considered to be his “virtual mentor”, and Bob himself.

Bob’s journey evolved through childhood piano lessons, the making of simple monophonic organs before age thirteen, and the making of his first simple theremin from a do-it-yourself magazine article at age fourteen. In 1954 at nineteen, Bob’s own design for a more refined theremin appeared in the same national publication. In 1961, the magazine not only published Bob’s latest theremin design, they put it on the cover. More than a thousand requests poured in for Moog theremins and kits. Although Bob’s synthesizer took center stage in 1964, he continued to revisit, improve and streamline his theremin designs, expanding their features and capabilities throughout his life.

As we explore the blossoming and maturing of Bob’s theremin work, certain leitmotifs come into focus. In addition to his innate affinity for the craft, Bob had a love of learning and a dedication to sharing what he learned with those who would most value what he had to offer. This dedication becomes readily apparent in the surviving literature, instrument owner’s manuals and correspondence with customers. A study of Bob’s first three published theremin articles alone paints a picture of a dedicated student mastering his craft, while gradually becoming a master in his own right.

RAMCO/R. A. Moog (1953 — 1954)

The Model 201 theremin holds a special place in music history, as the very first electronic musical instrument to be designed, made, and marketed by Bob Moog. The Model 201 appeared a full decade before Bob made a splash with his “Modular System” synthesizer at the 1964 AES convention.

The Model 201 was also the first theremin to be offered to the general public in a quarter century, ever since the demise of the RCA Theremin of 1929. Like the RCA, Model 201 employed vacuum tubes, as did all electronic devices, radios, televisions, etc., just before the dawn of the transistor era.

The Model 201’s origin dates back to 1949, when the 15-year-old future electronic music trailblazer and his engineer father constructed a simple theremin circuit from plans published in Radio News magazine. Bob was instantly captivated, and spent the next few years building one theremin after another, continually refining and improving each variant along the way.

In January 1954, the same magazine published the 19-year-old Bob’s DIY article on his refined theremin. The design included voltage regulation for greater stability, a built-in power supply, amplifier, speaker, and selector switches that enabled the performer to choose from one of four different overtone combinations. The total package was all enclosed in a compact mahogany cabinet with a black painted, silkscreened control panel.

Relatively few who tried to construct Bob's 201 from the magazine article succeeded. This may well have played a role in the young innovator’s decision to build and market complete working instruments. Construction challenges for the average hobbyist were many: In addition to the usual tubes, capacitors and resistors, the article called for 875 hand-wound turns of wire, to be wrapped in various layers around four differently shaped forms, for a total of eight inductive coil windings. Adding to the complications, the parts list called for a pair of television oscillator coils from a small manufacturer that were likely difficult for subscribers to procure, even then.

What was already second nature to the young Moog turned out to be elusive to his readers, who were left to flounder at the sourcing and precise physical construction of the handmade coils. Thus, it wasn’t likely finished instruments that Bob sold at first, but ready-made coil sets to aid those who were struggling to build his Model 201 design. A tiny advertisement in the March 1954 issue of Radio and Television News (as it was now called) advertises the kit of coils, and complete parts kits, as well as fully assembled theremins.

Bob estimated that he constructed fewer than two dozen examples of the Model 201. All were made in his father’s basement workshop. The senior Moog made the cabinets, while Bob hand-assembled all components onto the hand-punched and drilled metal chassis, soldering them together with point-to-point wiring. Commonplace printed circuit boards were as yet still in the future.

A significant feature of the Model 201 design was the pair of 2-position switches that formed an “Overtone Selector”, enabling the performer to select or reject various harmonics, to yield any one of four different timbre combinations. In addition to the fundamental tone, which is essentially a pure sine wave sounding much like a penny whistle, overtones could be selected to enhance and enrich the tone; the second harmonic, the third harmonic or a combination of both. Not only was this a departure from the RCA Theremin, which had only one available “voice”, but it also reveals that Bob was already thinking about how to obtain a variety of distinctly different sounds from one instrument, years before his modular synthesizer came into reality. Ever the innovator, the lessons that Bob learned from the Model 201 venture set the stage for the even more highly developed theremins that would soon replace it.

R. A. Moog (1954 – 1957)

The R. A. Moog Company’s second-generation Models 305 and 351 represent the next significant development in Bob’s instrument designs, and mark the first time that a Moog product was offered in basic and deluxe forms. If the R. A. Moog Model 201 of January 1954 represented an advanced and well-thought out first design from a fledgling young musical instrument maker, the Models 305 and 351 represented a fully developed and mature product of unusual sophistication, developed within a remarkably short period of time. The fact that these models appeared before 1954 came to a close, upon on the heels of the Model 201, reveals just how inspired and fertile Bob’s mind was during the early stages of his electronic music career.

As the Models 305 and 351 were both high-current vacuum tube instruments, we see voltage regulation carried over from the Model 201. Gone however, was the self-contained aspect. Amplifier and speaker were now external, enabling the instruments’ cabinets to have a sleek, lower profile. A five octave range was claimed for both the 305 and 351, from two octaves below middle C to three octaves above middle C.

The budget-conscious Model 305 was essentially a stripped-down version of the Model 351 described below. Unlike the Models 201 and 351, the end-user had to be content with only one sonic timbre or “tone color”. Of significance from a manufacturing and marketing point of view, both of the new models shared the same structural mainframe and cabinet, as well as the basic pitch and volume oscillator circuitry. Although the construction of these instruments had to share time with Bob’s university studies, the engineering foresight that they embody represents the beginning of Bob’s dreams of a mass-produced instrument.

The most significant new development found in the deluxe Model 351 was that in addition to the overtone selector introduced with the Model 201, a supplementary dedicated four-position timbre selector switch was added, to give the performer even more tonal options.

Bob called this new innovation “Synthetic Format”, and labeled the switch positions for the instrument families that he felt the new tones most emulated. In addition to the theremin’s Principal or native tone, these were Woodwind, Horn and String. By mixing and matching each of the switch positions of the “Overtone Selector” in various combinations with each of the switch positions of the “Synthetic Format”, a wider palette of possible sounds became available.

Even at this early stage, Bob was deftly engineering the internal circuitry to smoothly perform the actions of generating, clipping, filtering and recombining a variety of square and sine waves. Although technically not a synthesizer, the Model 351 Theremin represented an efficient, intricate, and electronically elegant way to arrive at a desired sonic derivation.

In addition to the pair of four-position Overtone and Synthetic Format slide switches, the performer’s interface included a bewildering array of manual controls that affected volume; a “Volume Adjustment” knob for the volume antenna sensitivity, “Soft / Loud” positions on the on/off/silent switch, and a “Volume” knob for master gain. Notable for their omission, are any references in the owners manual on how to set these controls. The manual does however describe, perhaps for the first time in publication, how to achieve a pleasing vibrato, in addition to clear direction on how to select and match the many timbre control options that the Model 351 had on tap.

Marketing the Model 305 and the Model 351


Thinking now like a true entrepreneur, Bob included a nicely produced booklet of owner instructions: “THE R. A. MOOG THEREMIN • What is it? • How is it played? • How does it operate?”. He expanded his product offerings to include the Model 400 amplifier, and provided a full one-year warranty. Each instrument was stated to have undergone “more than forty hours of exhaustive tests and adjustments to achieve uniform and optimum performance.” The booklet concluded: “Because of advanced design, quality control, and thoroughness the musician can own the R. A. Moog Theremin with pride and play it with confidence.”

Present-day examination of surviving examples of the Moog 351 theremin shows that, if anything, the superlatives in the booklet are an understatement. From the sturdy steel chassis foundation filled with top-grade components, to the highly polished mahogany enclosure and all of the wiring inside (still soldered by hand with numerous “point to point” individual wires), the workmanlike quality meets the highest standards of contemporary manufactured products by RCA, Zenith and other respected 1950s name-brands, and exceeds the quality of many other period manufacturers. Bob even typed up a set of basic servicing notes for the benefit of the dealer and end-user, available upon request, to provide more detailed troubleshooting or control adjustment advice to those who sent an appropriate inquiry to the R. A. Moog Company.

Bob maintained a professional, hands-on approach, and personally signed the type-written replies. List prices for the Moog products from a February 1955 price list were $178 for the Model 305, $216 for the Model 351 and $95 for the Model 400 amplifier, with special discount to dealers.