Author Archives: Reid Welch

The RCA theremin – 2 – The Pitch Control System

The RCA Victor Theremin

The construction and operation of the RCA theremin pitch control circuit. This installment deals with the construction and operation of the RCA theremin pitch control circuit. The heart of the system is a large “pitch control resonant coil” (PCRC). The PCRC is the tall coil mounted the left side seen when looking into the back […]

The RCA Theremin – 1

The RCA Victor Theremin

Part 1 of a technical essay about the RCA theremin by Reid Welch. This is the first of several installments about the RCA theremin. Our goal is to promulgate enough data to enable the skilled amateur to build an RCA equivalent, and to make the circuit less mysterious to the non-technical person. Discussion and corrections […]

More Original RCA Data

The RCA Victor Theremin

RCA theremin technical notes written by Reid Welch. The RCA Pitch Resonant Coil Consists of more than a thousand turns of approximately 38 ga. ( B&S gauge) SSC enameled wire wound on a 12″ tall by a 2 15/16″ diameter, 1/16″-wall phenolic impregnated fiber tube. Winding length- 10 3/4″ DCR 445 ohms Z at 1kHz […]

Dimensions of the RCA Oscillator

The RCA Victor Theremin

Notes about the RCA theremin oscillators by Reid Welch. Both RCA oscillators are identical, two-layer coils wound on a tubular fiber form about 1.5″ diameter by 1 3/4″ long. The wire is single silk covered (“SSC”) enameled wire approximately #30 B & S gauge. Turns per layer- about 75. The winding length is around 1 […]

RCA cabinet dimensions

The RCA Victor Theremin

The RCA Victor Theremin cabinet dimensions as measured by Reid Welch. At 11:07 PM 7/21/97 -0400, Charlie finished his report with: …here are the rca dimensions, as measured on dave weiner’s instrument: >Height from floor to top of cabinet 46.5″ >Height from floor to bottom of cabinet 22″ >Height from bottom of cabinet to top […]