Here is the Goldberg theremin as it is today, after restoration. It has a new set of hardwood legs, a mahogany finish and a new, nickel plated brass "lightning bolt" pitch antenna made by a master metal worker to match the original. Julius Goldberg was quite a showman and while the distinctive antennas may look striking on stage, the pitch antenna is not practical for precision playing because the configuration of the electromagnetic field emanating from it is as irregular and jagged as the antenna itself. When I record with the instrument, I replace the "lightning bolt" with the standard RCA rod that came with the theremin. The Julius Goldberg RCA theremin can be heard on two cuts from my theremin recording, MANY VOICES.
A close-up of the front of the theremin shows the brass PITCH and VOLUME escutcheons that were part of the 1929 RCA theremin design.
The open cabinet doors reveal the replacement power transformer (the black box in the lower right section of the cabinet). The original RCA transformer blew up on the day of one of John Snyder's concerts. John was lucky to find an expert who managed to replace it just in time for the performance. Other than the transformer, and one or two small additions made by Julius Goldberg himself, the theremin is entirely original.
As vintage theremins age, their capacitance degenerates as the plates on the old fashioned "trimming condensers" (the three white cards just below the vacuum tubes) begin to wear. This degeneration causes the theremin to lose its high notes. It can be easily corrected by the addition of a few pico farads of capacitance across the circuit. Exactly how much to add must be determined by trial and error. In the photo above, you can see the "alligator clips" that I have added to the trimming condensers to facilitate experimentation.