A Mysterious
1937-Vintage, Custom-Made Theremin

[Editor’s note: While the particulars of this article have changed dramatically since I originally wrote and posted it, I decided to leave it here, as is, in the spirit of the "stream-of-consciousness" nature of my website.]

Prologue: The Mysterious Theremin Materializes
Act I : It’s Here
Act II : Such Stuff As Dreams Are Made Of
Act III : The Gentleman From Miami
Epilogue : All’s Well That Ends Well

Prologue : The Mysterious Theremin Materializes

In the Spring of 1996 I acquired, through most mysterious and spiritual means, a vintage tube-type theremin. Not an RCA theremin. A custom-made theremin. At first, we thought it might possibly have been made by Professor Termen himself. (More on that later in this article.)

The type and configuration of components identifies it as mid- to late-1930s technology.

This is the cabinet before restoration.

Here’s the deal: Through an organist colleague on the Internet (thanks a million, Frank!), I met a man in Florida who had two theremins for sale. One, a standard RCA. The other, a custom instrument based on the RCA but with many extra features — special voicing filters, unusual (for theremins) tubes and components (in many respects different from the standard RCA), and so on.

I got on the phone to the seller, who sent me pictures and a description of the custom theremin from the seller. It is what he says it is.

The wooden cabinet looks very much like the RCA except for the front area (not the music desk location, the vertical-most front side), which contains a control panel set into a black metal plate about 15" wide and maybe 4" tall. It’s got four big dial controls, in two groups of two; in the center separating the two groups of two dials are two switches and red pilot light jewel above them. The switches, standard ball-end metal toggle switches, are labelled “standby” and “power.”

About the four dials: the knobs are ornate, 8-sided, rounded bakelite-type knobs about an inch in diameter. Behind each knob, engraved on the control panel, is a large circle, about 3" in diameter, white writing, each marked off 0-10 + half-degrees and labelled above each circle with engraved lettering:


Close-up of the control panel.

The first circular dial is labelled “gain” at the bottom, between the (1) and (10) increments.

Dimensions of the cabinet:

46.25" tall less pitch antenna

19" wide, 12" deep

(The top has a long and wide heat vent, larger in area than the RCA)

The CABINET has a stamp showing that it (the cabinet, not the theremin) was built by the William Rock Manufacturing Co., Baltimore. The cabinet is overall in good shape, does show some scratches and signs of wear but nothing major.

What’s inside the cabinet:

The large volume coil has been coated with some sort of spray-coat seal, metallic blue in color; the TWO pitch coils (more on that momentarily) are encased in tall, rectangular-shaped silver colored metal cases with rounded-off corners with small circular holes in the top to access the two (for a total of FOUR) pitch caps on each coil.

The main chassis is coated with black wrinkle-finish or hammertone (instead of the brown enamel of the standard RCA chassis). Same for the transformer, which is labelled “Ameritran Audio Transformer.”

There are two large “Cornell-Dubilier” condensers, in metal cases with yellow/blue paper labels.

All the internal wiring is original waxed-cloth covered.

The tubes:

A tube hidden behind a variable oscillator coil looks to be a 6A8 used as the variable oscillator and fixed oscillator operation.

A beautiful 6-pin, red-based, blue-glass Arcturus, Wunderlich tube acts as a blender.

Two 6N7s act as frequency filter amplifiers.

6B8 and 120 team up for variable volume control.

Two 6F6 tubes hooked in Push-Pull provide at least 10-15 watts final audio output.

5Y3s act as full-wave rectifiers.

The seller said he purchased this instrument from the estate of Phillip Stout, a man who had worked for RCA and indeed with Prof. Theremin on development of the theremin. (n.b. There are no RCA trademarks anywhere on it.) [If anyone out there has any information on Phillip Stout, I’d be most grateful if you would share it with me.]

The seller had originally thought he might fix it up one day and learn to play it as a hobby — but in his words, “You know how that goes.” It sat in his garage for a number of years. Then when I contacted him, actually enquiring about the RCA he had for sale, not knowing he had the custom instrument, he mentioned it. I said, “Well, actually, I would certainly rather have that custom instrument than the RCA. If you ever decide to sell it, please let me know.” The long and short of that comment was that he decided right then and there to sell it to me!

(He has since also sold the RCA theremin.)

I won’t go into a lot of the financial details but will simply say that his asking price was certainly reasonable. However, with my current budget and financial status it may as well have been a million dollars. I told him that, quite frankly, but said if anyone else made him an offer on the instrument to please let me know first and I would see what I could do.

I just started putting it out there. I literally told everyone about it who would listen — not expecting anyone to hand out donations — I just HAD to talk about it! I also did some serious praying. No, I did not say, “Dear God, Please let me have this theremin!” Rather, I turned over my inability to acquire it; made peace with that and simply said, “Your Will Be Done.” More than anything else I was praying for serenity and acceptance of the situation no matter how it turned out.

Then one day I got a call out of the blue from a woman I have never met. She is the mother of a friend of mine. She said, “I understand you have an opportunity to acquire a rare theremin but don’t have the means to do so.” I confirmed that was the case. She said, “Well, I am in a position to help make that happen for you. I am willing to loan you the money. On what terms could you repay it?”

Well, to cut to the chase ... I am expecting delivery of the instrument, fully restored inside and out, around the end of June! [n.b. that was written back in April; the theremin ultimately arrived in early September.]

When we originally talked, the seller was going to sell it as-is. However, he became inspired by the outpouring of my friend’s mother’s generosity and decided that he would make sure it was fully functional when I received it, even guaranteeing it would work to my satisfaction or I could receive a full refund.

He is an antique electronics expert; has had a number of articles published on vintage radios, and has a fine collection of restored instruments. He said when I receive the instrument it will be like brand new, even to refinishing the beautiful, butter-colored oak and mahogany cabinetry.

To those readers who are not thereminists, nor particularly interested in theremins, and may wonder what all the fuss is about, let me clarify by saying that this could be akin to discovering a Stradivarius violin — or, if you will, an original Fender guitar! If it turns out that this instrument is what we think it is, then it will be one that came from the very hands of the inventor himself — and according to perhaps the top expert in the field, Dr. Robert Moog, it appears that that might indeed be what it is, based upon my written description about it. But any way you look at it, it’s a most incredible and serendipitous find!

Let me share the final paragraph of a letter I got the other day from the seller: “Many years of restoration work on electronic instruments give me the insight to see that this is a quality-made and designed instrument. It is better someone like you, who can put the magic touch on it, have this fine instrument.”

Act I : It’s Here

Well, the vintage theremin has arrived.

I’m still in shock I think. Every so often I have to walk out there and look at it again, to make sure it’s really there.

I am still pinching myself. Ow! Stop that!!

Seriously, I have this gorgeous buttery-colored mahogany theremin in my living room with copper antennae and I can still hardly believe it.

It suffered very slightly from its trek northwest; nothing major thank goodness but there are some small problems that my friend Dave Weiner and I are going to work on. Not the least of which is a very erratic pitch control knob. The adjustment knob is too loose, very touchy and difficult to adjust precisely and does not stay where you put it. volume circuit needs some adjustment, same for pitch, it goes too high. i am working on it.

We also need to reconfigure it for left-handed playing, so far I have had to stand on the wrong side to play, but it does work that way, just kinda awkward to reach the controls.

(Some people might take exception with this, noting there is a standard “way” to play most instruments, e.g. you don’t play a piano or violin backwards; however, there is precedent for left handed playing; not the least of whom in the person of noted thereminist Henry Solomonoff, a Rockmore/ Termen/ Rosen (et al) contemporary, was a leftie. He’s the man in the theremin film who talks about being a left-handed thereminist in the Theremin “orchestra.” And who recently passed away.)

The tone of this instrument is so exquisite...

My GOD, the sound. In the lower registers it groans like a big, fat Voix-Humaine organ stop. As you ascend the scale it smoothest and blooms out into a gorgeous soprano tone.

It’s not quite as “edgy” in timbre as Clara Rockmore’s; at least not as it is now adjusted.

3. Get this: There are no less than FIVE separate adjustments for pitch — the external one of course, then on the TWO pitch coils inside, ONE FOR EACH OSCILLATOR, each of the two has TWO adjustments.

(The standard RCA has only ONE pitch coil that is fed by the two pitch oscillators, and at that there is only one pitch adjustment.)

4. Same for the volume circuit. Inside the chassis there are THREE volume controls — a master level; one to set the distance of absolute “cutoff” which does not seem to be quite properly working; we are going to explore that; and one to adjust the expanse of motion. Then again, the external volume control.

(Again, the RCA has only the external volume control plus ONE inside.)

The tricky part with ~this~ theremin is all the controls are interwoven, e.g., you adjust one control and it affects all the others. You adjust another one and it also affects the others, including the first one you adjusted. so it’s going to be a constant, tedious process of going back and forth, from one control to the other, to get to that point of perfection, of musical clarity. A tremendous challenge with this instrument. but, boy, i have a feeling when it’s ready, it is gonna put us ALL into orbit.


Something else lacking on the RCA instruments that mine has:

There’s a master harmonic filter adjustment inside plus two more on the outside to adjust tone quality. these also don’t seem to be functioning as they should; i think they need to be cleaned or maybe replaced; as you turn the various knobs there are dead spots where the timbre just drops out, or where it suddenly BLARES out — seems like dirty contacts. These are the old-fashioned plate-type ’pots’; with a carbon contact moving around a circular row of resistance contacts. The man who rebuilt this is a great electronics whiz but not a professional musician, certainly not a thereminist and did not know quite what to make of all the controls. So there is still some work, both mechanical and tonally, yet to be done.

I have to practice on it; get accustomed to the different response and spatial relationship of intervals, which is all quite different from my other two instruments.

But most of all, it has that gorgeous, hollow sound in the bottom-end that I just KNEW was gonna be there; unlike my two modern models which, in the low registers, sound like the bass end of a brassy ’60s analog synthesizer — BRRFFFFTTT!!!

Act II : Such Stuff As Dreams Are Made Of

Well, the vintage theremin has come and gone. The following explains all.

Excerpts from my email to Robert Moog,
sent in early October 1996:

Dear Dr. Moog:

Are you interested in treating this [1927 theremin] patient, perhaps a direct offspring of Leon Termen???

Yesterday’s exultant elation is matched today by debilitating disappointment.

There are a few significant problems that my very brilliant electronics engineer friend cannot solve.

First off, the seller had tried to configure it for left-handed playing but he ultimately could not do this. He sent it still arranged for right-handed playing. Thus, for my purposes it is virtually useless. I can’t relearn how to play right-handed! If that were the natural way for me to play I would have done that in the first place. I can’t very well continue to play it standing on the wrong side; it looks ludicrous; the volume antenna is angled the wrong way and I can’t reach the controls.

ALSO: Most all of the numerous controls do not work properly:

The two harmonic controls on the front are erratic and have dead spots and hot spots; engineer said he could not fix that because they are sealed capacitors. Yet these are vital in sculpting THAT sound — that perfect, elusive theremin sound.

The various volume adjustments do not seem to be working properly. There is a control inside that the seller said would regulate the relational point of absolute cutoff; that is, varying the point in space at which you get silence as you draw your hand toward the volume loop. What happens with this control is for the first, say 70% of rotation there is no effect; then in a space of about a sixteenth of an inch there is a slight reduction in overall volume, then past that it cuts the sound out completely. Somewhere in the sixteenth-inch area is a sweet spot where it makes the cutoff work, SORT OF, but you never get complete inaudibility.

Which brings me to the other thing — he had said this instrument ought to be lightning fast in volume because of the souped-up nature of the volume circuitry. Well, so far, as best I can tell it is no better than the off-the-shelf RCAs I have played. It’s fairly prompt but not immediate — playing pizzicato is out of the question; no Fuleihan for me on THIS baby.

I guess you can imagine how crushing the disappointment is after having waited nearly five months for this to arrive and it doesn’t work for me. The biggest disappointment is, I can HEAR the sound. I mean, the tone quality is there and it is gorgeous. Exquisite. Ravishing. Which makes this letdown all the more bitter.

I guess I need some sort of estimate as to what you might charge to “revivify” this instrument for me.

I did of course have high hopes and excitement for owning what seems to be an original Theremin — at any rate certainly a very rare and valuable one, an instrument the likes of which no one else has ... but even as valuable as it is, it is worthless to me if I can’t play it.

Moog agreed to evaluate the instrument
so I packed and shipped it to him.
Following are excerpts from his assessment.

October 3, 1996


We performed the following observations and work on Charles Richard Lester’s vacuum-tube theremin:
1. Cleaned out all the plastic peanuts.
2. Traced selected portions of the upper chassis circuitry.
3. Repaired several wires that were frayed or that had defective insulation.
4. Measured the DC voltages and observed the waveforms at selected points in the upper chassis.
5. Installed a connector in the 110 volt wires between the lower and upper chasses.
6. Visually inspected the entire upper chassis.


1. The ’original’ components and wiring appear to be from the late 1930’s. The tubes are more modern than those used in Clara Rockmore’s or Lucie Rosen’s theremins (early ’30’s), but are probably not post-World-War-II.

2. The ’original’ wiring was carefully and competently done. It could have been done either by a professional instrument builder or by a skilled amateur.

3. Many original components have been disconnected, and more modern components have been soldered in their places. This is especially true of ceramic and electrolytic capacitors.

4. The pitch circuit is not like any of Leon Theremin’s designs that I know of. All of Theremin’s designs use a large ’pitch antenna coil’ in series with the pitch antenna, a circuit configuration which gives optimum pitch control. On the other hand, the pitch circuit of this instrument resembles that of many ’home-built’ and ’do-it-yourself’ designs that I’ve seen over the years (from 1932 to 1996). My experience is that theremin pitch circuits without pitch antenna coils do not perform optimally.

5. The volume circuit does use a volume antenna coil. It looks very much like the ones that were used in the RCA theremin of 1929 and 1930. In fact, the volume control circuit seems to have been lifted right out of the RCA design, including the use of a now-rare ’120’ tube.

6. The two pitch oscillators and the one volume oscillator appear to be marginally stable and poorly designed. The volume oscillator tube is operating far beyond its maximum voltage rating. So is the 120 tube.

7. I do not recognize the ’second harmonic’ and ’third harmonic’ circuitry. At this point, I don’t know how it’s supposed to work,- or if it ever did work.


1. It is extremely unlikely that Leon Theremin ever had anything to do with the design of this instrument. I say this for the following reasons:

a) Every space-controlled instrument that Theremin made, from his first published circuit in the early 1920’s to the instrument that he played at Stanford University in 1992, used a large antenna coil in series with the pitch antenna. That is an extremely important feature of authentic theremin design. On the other hand, this instrument has been designed not to use a pitch antenna coil.

b) Leon theremin did not use the ’120 tube’ circuitry after 1930. The ’120 tube’ circuitry gives a sluggish volume antenna response, whereas the circuits used by Theremin after 1930 give rapid volume antenna response. It’s hard to understand why Theremin would have used the ’120 tube’ volume control circuitry in an instrument that was built in the late ’30’s.

c) Theremin was a meticulous, professional designer of electronic circuitry. All of his designs that I’ve seen are stable and well within the rated voltages of the tubes. On the other hand, the oscillator circuits of this instrument are unstable. In addition, the volume oscillator and the 120 tube operate far beyond their maximum rated voltages.

2. This instrument was probably designed by an amateur electronic technician, or by someone who was not familiar with this type of circuitry.

3. This instrument was originally built by someone with good electronic assembly skills and a well-equipped electronics shop.

4. At the present time this instrument is not playable. It may have been playable at some time in its history. If it was, then the pitch antenna response was very different (and much less playable) than Leon Theremin’s instruments, and the volume antenna response was as slow as that of the old RCA theremins.

5. We’re not in a position to guarantee that this instrument could ever to be made to work reliably, or have good playability, without a major amount of redesign and rebuilding.

Bob Moog

Well. Talk about a kick in the ... antennae!

After all the buildup, the excitement, the waiting for this instrument since July ... I was really bummed out about this and was afraid I was now the proud owner of a theremin white elephant.

Act III : The Gentleman From Miami

Out of the blue, I got an email in — what, late September or early October — from a fellow in Florida named Reid Welch. We struck up a new friendship on the ’net and via telephone. I was quite amazed to find that Reid is another left-handed thereminist! He’s a piano tuner, technician and finisher by trade, and is also a very talented electronics whiz.

I told him all about the vintage theremin, which I had nicknamed “Baby Huey.” I filled him in on Moog’s assessment; the whole nine yards. Well, was I ever surprised when Reid expressed interest in buying the theremin from me. “What are you, nuts?!” I asked. I made sure he understood that it was, at this point, not a viable instrument. But that did not seem to matter to him; he really wanted it. So off to Florida it went.

Meanwhile, there I was ... again without a concert-quality theremin. Yes, the Etherwave is very nice but it does have some disadvantages that I consider serious enough to prevent it from being used by a classically oriented thereminist, as I am.

Reid had mentioned he had a Big Briar 91-A, that he had had custom made as a left-handed instrument. For various reasons, he never was really happy with it so he did not use it. We talked about that, and he offered to send his 91-A to me to evaluate, then to consider either purchasing that one from him or to help me make a decision whether or not to order a new one from Big Briar, which I had been thinking about.

So, believe it or not, that is exactly what Reid did — sent his theremin off to me, who was, to him, for all practical intents and purposes a total stranger!

The 91-A arrived. I played it, tried it out, inspected it. And fell in love with it. It is an absolutely marvelous theremin! It does not have ~exactly~ the tone quality of the original tube instruments, but it’s darn close — and that slight lacking is more than outweighed by its superb playability in every regard — timbre, linearity of pitch (notes are more evenly spaced, unlike most other theremins I have played — including the Etherwave — where the higher up the scale you go, the closer the notes come together). And it is LIGHT! Baby Huey weighed in at something like 75 pounds. In retrospect, the prospect of lugging that thing around all over the place is not a jolly one! The 91 is just a fraction of that weight. Furthermore, with no tubes to burn out or break, it will be far more reliable, to be sure.

Epilogue : All’s Well That Ends Well

So ... There was a dark “second act” to this drama, just as all good theatre, however, it has drawn to a magnificent, brilliant and triumphant third-act conclusion!

And certainly portends to more exciting drama in the future... stay tuned!


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