• Registry
  • RCA Theremin Registry
  • Registry: Map Version
  • Registry: Grid Version
• The RCA Theremin
  • Introduction
  • Identification & Serial Numbers
  • Frequently Asked Questions
  • Setting Up for Playing
  • Sound, Tone, & Tube Advice
  • Troubleshooting Advice
  • A Note on Capacitors
  • Schematics & Manuals
  • Shipping & Handling Advice
  • Second-Generation Prototype
• Lev Built
  • Introduction
  • 1925–26 Pitch Only Theremin
  • 1929 Rockmore RCA Theremin
  • 1929–30 Theremin
  • 1929–30 Solomonoff Theremin
  • 1929–30 Greenfield Theremin
  • 1929–30 North Carolina Theremin
  • 1933–34 Theremin Studio Theremin
  • 1937–38 New York Theremin
  • 1938 Rosen January Theremin
  • 1938 Rockmore Theremin
  • 1938 Rosen September Theremin
  • 1961 Soviet Theremin
  • 1932 Rhythmicon
  • 1960s Rhythmicon
  • 1933 Theremin Cello
  • 1937 Theremin Cello
  • 1978–79 Terpistone
  • Missing In Action
• About
• Services
  • Repair and Restoration
  • Replica Parts, Tubes, and Crate Plans
  • Experience
• Classifieds

Should I replace the old capacitors in my RCA Theremin?

No, this is generally not recommended. See our thoughts on capacitors in RCA Theremins.

Can you provide information about my Moog Etherwave (or Pro, series 91, PAIA, Enkelar, etc.)?

We only deal with 1929 RCA Theremins and Vintage Lev-built or Teletouch instruments on this web site. If you have a Moog 201 or 351, however, we would be interested to hear from you and you can contact us at experts @ rcatheremin.com

How much is an RCA Theremin worth?

Based on sales results that we've been tracking for the past several years, the range is about $3,500 for a basket case needing full restoration, to about $13,000 for the best original, properly working examples.

The RCA 106 Loudspeaker ranges in price from about $200 to $500 depending on condition, not including the cost to ship.

Can you tell me what my theremin is worth?

We are not certified appraisers at this time. However our unofficial appraisals have been consistently more on target than the professional appraisals (legitimate and otherwise) that we have seen. We take far more specific factors into account than the general appraisal services do, and can provide up-to-date valuations on your RCA theremin. Contact us for more details.

A note on appraisals: We have seen seemingly inflated Certified Appraisals of RCA Theremins and RCA 106 Loudspeakers, as part of eBay auctions and other auction services from time to time. These tend to be significantly higher than the high end of the range noted above. Frankly, we don't know where they're getting their information, but it's possible that some private sales have brought higher figures than those we've been able to track.

Follow the Do's and Don'ts listed below to keep your RCA Theremin in its most valuable condition.

My RCA Theremin has no legs. Is this a rare variant? Is this stand original?

All RCA Theremins left the factory with four permanently attached legs and stand 47 inches tall (64 inches with antenna). Many RCA Theremins had their legs cut off to make them easier to transport. In some cases a table upon which to place the truncated instrument was fashioned by attaching the original legs to a small platform top.

Contact experts @ rcatheremin.com for information on new replacement legs for your RCA Theremin. Note that correct installation of legs requires some cabinet disassembly, or an alternative method for a functional replacement with fewer attachment points.

Is my RCA Theremin Missing Parts? Where can I get replacements?

There are a few parts of the RCA Theremin that are commonly lost. These include the pitch and volume antennas, the pilot lamp jewel & ring, pilot lamp extender, doors, music shelf and small metal escutcheons labeled On/Off and Play/Off that mount to the switches.

Commonly missing parts of RCA Theremins.

Contact experts @ rcatheremin.com for current availability, cost and wait time for high-quality replicas of the above listed parts, as well as for complete reproduction RCA Theremin cabinets.

Where can I sell my RCA Theremin?

Classified ad sections appear on RCATheremin.com's Classifieds page and ThereminWorld.com. To broaden your prospective audience, you can list your theremin for sale on eBay.

Where can I find an RCA Theremin to buy?

Check the resources noted directly above. Beware of fake eBay auctions and fake Craigslist ads for RCA Theremins, both of which have been seen on occasion.

Where can I get vacuum tubes for my RCA Theremin?

We can supply tested, guaranteed vacuum tubes at reasonable prices for your RCA theremin, or you can search for vacuum tubes on eBay (buyer beware) or from antique radio parts suppliers. It has been our experience that some established dealers occasionally send out vacuum tubes that in fact have problems. Vacuum tubes that we offer are guaranteed and have been tested for function in an actual RCA Theremin, a claim that few other suppliers can make.

Where can I get my RCA Theremin repaired?

We offer experienced and conscientious repair, restoration, voicing and adjustment of RCA Theremins. We can also provide non-invasive modifications, and a simple timbre adjustment control. Contact experts @ rcatheremin.com for current pricing.

Whether buying, selling or obtaining service, to ensure the safest transit for your RCA Theremin we strongly recommend having a shipping crate made to our specifications (We have plans for sale on our Parts page). Prior to considering shipping your RCA Theremin for repairs, please take a few minutes to review the Troubleshooting Advice section.

Why do you call the power supply an SPU?

RCA's power supply designation in the late 1920s was Socket Power Unit. When the RCA Theremin came out in 1929, AC radios were only a year or two into regular production and were stated to be wired for light socket power. Many electrified homes of the era had only one outlet per room, and some rooms were wired only for a ceiling lamp. Unscrewing the light bulb from the ceiling fixture and replacing it with a Y adapter allowed the light socket to accept an Edison-base AC appliance jack, into which the appliance would be plugged, hence light socket power, or simply socket power.

On my theremin, the arrows on the control knobs (and/or "zero beat" position) are different from your picture. Why is this?

Our control knob images depict the arrow and zero beat position as they would appear on a correctly calibrated RCA Theremin. Due to changed component values, incorrect trimmer adjustments and incorrect position of control knobs on their shafts, your theremin may be different.

Do's & Don'ts

Do:

• Take the time to carefully polish the cabinet. Old English Lemon Oil, Orange Oil or similar wet preparation works wonders on a dry finish. Follow the directions on the bottle. If the finish is in good condition, waxing with a fine furniture wax is an option but may require a lot of hand-buffing to eliminate residue, and will be more prone to fingerprints. Avoid getting polish or wax in cabinet joint crevices, to enable easier future repairs to these joints, if needed. The metal trim parts, other than the antennas and antenna sockets (which are nickel plated), were given an antique-bronze finish at the factory. These parts include the "Volume" & "Pitch" control knob tags, toggle switch bats, embossed metal escutcheons, knurled nuts, music shelf hinges and back door knobs. When cleaning or detailing the cabinet, take adequate precautions to avoid polishing through the thin bronze finish of these parts. If it is ever necessary to remove the switches, a thin plastic circle template placed over the switch nuts, and a small plier with padded jaws will help prevent marring the hardware and cabinet finish.
• Tighten the screws that help secure the legs. These screws are located under the floor of the cabinet (outside the cabinet bottom), at each corner, and go in at an angle. Always use a correct size screwdriver in good condition, to avoid marring the slots in the screw heads. Don't allow unmarred screws that have survived more than 80 years with pristine slots, to get damaged by ill-fitting or carelessly handled tools.
• You can carefully dust and vacuum inside the cabinet with a soft brush attachment. Be very careful to avoid contact with the tall coils, and use care when vacuuming the wiring harness. A soft brush, such as a worn out toothbrush, carefully handled, will aid detailing the wires.

Don't:

• Don't splice a new plastic power cord onto the worn-out remnants of the original cord with wire nuts. Not only does this look terrible, it is shabby treatment of your historic antique theremin. Correct-appearing braid-covered AC wire (UL listed and safer than the original) is available from antique radio parts suppliers. If possible, get a carefully selected, qualified electronic technician to replace the power cord from the inside of the SPU, properly soldered and insulated (heat shrink tubing is best—avoid electrical tape for the same reason noted above). The wires connecting the accessory AC socket may also need to be replaced. If you own a RCA 106 loudspeaker with original power cord, chances are that it will need replacing as well, as may the speaker wire and pin plugs if they are damaged or missing. Always use appropriate materials and methods to uphold the value of your instrument.
• Don't pull the vacuum tubes out of their sockets by the glass. Always grasp the base. To avoid damage to the internal vacuum tube-socket contacts, do not rock the vacuum tubes more than a few degrees while exerting steady upward pressure. Do not yank the vacuum tube out suddenly, as you risk breaking the vacuum tube as it flies into the cabinet top, with possible injury to yourself.
• Don't wash the glass on the vacuum tubes until you've located the lightly printed vacuum tube number on the glass (UX-120 will usually have the vacuum tube number on the base). These numbers are water-soluble (let alone Windex, etc.), and once removed make it harder to identify the vacuum tube.
• Don't store the antenna inside the cabinet when not in use. This risks permanent damage to the delicate resonance coils.