1930 Second-Generation Prototype RCA Victor Theremin

RCATheremin.com is proud to unveil this one-of-a-kind, rarest RCA Theremin in the world!

What Do We Know About This Instrument?

The stuff of legends. Lost for the better part of a century, the only tangible evidence that the new model with self-contained speaker ever existed at all was in the form of rare corporate ephemera first reported in Dr. Albert Glinsky's masterful biography, Theremin: Ether Music and Espionage (published in 2000). It was long thought to have not survived, and has remained in obscurity for most of its existence. While its original supporting stand has not surfaced, the all-important primary instrument cabinet, complete with all of its essential internal components, has.

Why is it Special?

Dr. Glinsky reveals that RCA's show division manager, George H. Clark, conducted a survey of five hundred visitors at radios shows where the first-generation theremin was being demonstrated. The resulting suggestions, in combination with efforts made by RCA's marketing department, production, and design engineers, led to the creation of this second-generation prototype. Embodied in this reimagined form, the theremin appears less alien, closely resembling some radios of the era. The new design reflects what RCA's sales department felt the electronic consumer of the day could relate to with greater ease.

Convenience improvements included moving the control panel from the front of the cabinet, to a face-up postion under a hinged lid. When opened, in addition to providing access to the controls, the lid with its built-in ledge becomes a sheet music rest. Safe storage for the antennas is provided under the lid when the instrument is not in use, a feature sadly lacking in the first and ultimately only production version of the RCA Theremin.

Although the details of the survey responses are currently unknown, a thorough study of the physical evidence, as represented by this rare survivor, points to the specific nature of the lost communications. A hypothetical reconstruction of the suggested improvements, along with technical details are represented in the following lists:

User Experience

• Combination lid/music shelf
• Built in speaker simplifies setup
• Protective rattan caning over the grill cloth
• Dummy speaker grill on opposite panel for visual symmetry
• Shortened volume loop antenna, repositioned
• Redesigned pitch antenna socket for convenient installation
• Detachable matching stand containing power supply, for easier transport
• Evidence suggests a reduced playing height, for improved ergonomics in relation to antenna positions

Physical and Technical Changes compared to original RCA Theremin

• Built in speaker with acoustically transparent grill cloth
• The heat-producing power supply was located in the supporting stand, away from the heat-sensitive upper chassis
• Additional ventilation for improved convection air circulation would result in more stable pitch and volume
• Upper ventilation slot on the original RCA Theremin had a 4.5 total square inch area, whereas the new model prototype initially had a 7.5 square inch ventilation slot
• The 7.5 square inch ventilation slot was subsequently filled, relocated, and doubled in area to 15 square inches
• Resonance coils are suspended from underside of control panel
• Service door moved to performer's side of instrument
• In conjunction with relocating the service door, the chassis was reoriented 180 degrees for service control access
• As a result of rotating the chassis, the vacuum tube layout was likewise reoriented
• Type 45 output tube indicates modification for greater volume
• Type 45 volume oscillator tube for more streamlined power supply design

Prototype Work-in-Progress Modifications

• Pitch coil relocated from preliminary position
• One volume antenna socket relocated, to change loop from slanted to flat orientation
• The initial ventilation slot location interfered with the speaker mounting and was relocated
• Speaker mounting holes relocated and patched, indicating a possible change in speaker model

Parts Utilized from Current and Former Production Radios and Theremin

• 1928 Radiola 60 chassis, with vestiges of the radio components and chassis stamping features
• 1929 Victor R-32 radio Jones plug
• 1929 RCA Theremin resonance coils, G.E. version
• 1930 Radiola 80 knobs
• Speaker cloth as utilized on various RCA radio products
• Additional components as found in the RCA production lines

Who Owned This Instrument?

Previously owned by Ron McClellan.

Where is This Instrument Now?

Musical instrument collection of Wally De Backer.

Tube Complement:

• 80 (1), 27 (3), 24A (1), 120 (1), 45 (2)
• Since the power supply and the supporting stand have not surfaced, the full tube complement is unconfirmed.
• Audio output power: single-ended 45

Schematics

Not currently available

Photos

Photos: Will Joines

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