Julius Goldberg's RCA Theremin

YouTube via copperleaves — June 13, 2010 — "This is the unique 1929 RCA theremin that was once the property of Leon Theremin's assistant, Julius Goldberg. One of the things that makes this instrument so unusual, are the "lightning bolt" antennas that were created for it in the 1930's. For the purpose of this video, I have removed the cabinet doors in order to be able to show the inside of the instrument.

One of the problems that RCA theremins can develop over the years (this instrument is more than 80 years old) has to do with the degeneration of the "trimming condensers". These are the three little white cards that hang from the chassis. You will notice that each card has a trimming screw on it which allows the user to adjust the range of the instrument as well as the volume response. Turning the screw to the left or the right fine tunes capacitance by pushing two plates together on the inside of the card. Over the years, these plates naturally degenerate and lose their capacitance (causing the pitch range of the sound to fall lower and lower over the decades) so extra capacitance has to be added in order to maintain the integrity of the instrument. This can be done easily by adding a capacitor to the circuit. I have done this by connecting small alligator clips to the poles of the circuits and then inserting capacitors that will return the instrument to the original RCA specifications. By leaving the clips exposed (you can see them in the video) I can access them easily and adjust capacitance without having to disassemble the theremin.

The elaborate speaker stand that you see behind me, is an exact replica of the "sprite" speakers (there were originally three of them) that were created for the "Electrio" in 1931 by Vincente Minnelli when he was working as a set designer at Radio City Music Hall. Minnelli later went on to become one of Hollywood's most celebrated film directors of the 1940's and 50's. Unfortunately, the original stands disappeared long ago. They are very top heavy and they probably just fell apart.

It was felt at the time that the theremin, theremincello, and theremin keyboard (which formed the "Electrio") was not very interesting to look at from a distance, so these spectacular Art Deco speaker stands were created to look impressive from a distance. They were almost eight feet tall (this reproduction is about 7' 8" tall) and were very fragile. The stand you see in this video is equipped with a CLARATONE speaker specially designed for use with a theremin.

The piece I am playing is CHE FARO SENZA EURIDICE from C. W. Gluck's opera, ORFEO ED EURIDICE.

If you would like to know more about Julius Goldberg, and see some photos of the original sprite speakers, please visit my website:

http://www.peterpringle.com"

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