1929 RCA Theremin for sale

Posted: 12/5/2013 7:47:45 PM
RS Theremin

From: 60 mi. N of San Diego CA

Joined: 2/15/2005

"I would prefer someone that will pickup the item in Kansas City and pay with cash"

Here in Los Angeles that statement is reworded as "You will be robbed"?

Don't limit yourself, there may only be one person in the world interested

The simplest thing you can do for some creditability as you say it makes sound is to hold a digital sound recorder near the speaker and record a sample not playing any tune. Post the sound file, I will for you if sent to me and will give you a link to reference it. A theremin is such a simple process viewing the sound in software speaks volumes. I am amazed it slightly works.

Those sockets with all the wires look like experimental test sockets or something?


Posted: 12/5/2013 8:25:49 PM

From: Colmar, France

Joined: 12/31/2007

Potential buyers, take care, it looks to me like this instrument is highly modified and far away from the original state!

- They tell that "the UX-171A is missing" and it emitted a sound though: That's highly improbable because it can't sound with one of these tubes (there is normally one for the volume oscillator and one for the AF power amplifier) missing. 

- In contradiction to what was stated above, the pictures show an empty socket for one of the three UY-227 tubes.

- Most tubes seem to be mounted on socket adapters which is definitively NOT original!

- There is another tubes and transformer chassis (amplifier?) besides the power supply chassis which is also not original!

- There is a 6H6 double diode on the RF chassis which (as far as I can remember) has never been seen in an original RCA/Westinghouse theremin.

- Both audio transformers on the main chassis are missing. There is something which looks like a metal tube on an adapter socket in place of the first one. Even if it was an audio transformer in a metal tube housing it's obviously NOT the original GW-42 type.

Other things which look rather dubious:

- This instrument was already for sale on ebay, craigslist and other platforms and did apparently not get sold...

- The phone number is registered for a recycling center...

- Payment methods with fraud protection for the buyer (paypal, credit card) are not accepted...

Before investing a single cent into this potential trash, please check with Andrew Baron or Mike Buffington from rcatheremin.com! If I were about to sell a true original RCA/Westinghouse I'd get an expertise from them before putting it on sale.

Posted: 12/5/2013 9:37:56 PM

From: Colmar, France

Joined: 12/31/2007

The seller made an addition to his posting, calling me a "crackpot from France" and my comments "stupid and uninformed". But he makes no attempt to explain the obvious discrepancies in the circuit design and chassis layout which I revealed. Nor does he explain why he refuses serious and protected payment methods.

Offense is the best defense? Or just gobbledygook from an impolite and uneducated whatever being?

Has this instrument perhaps deliberately been modified? By whom? For whom? For which reason? Who was or were the previous owner(s)? Please accept my apologies but as long as all this is not explained, the whole thing remains very dubious.

Posted: 12/5/2013 10:37:11 PM

From: Colmar, France

Joined: 12/31/2007

Ah... Mike Buffington made similar observations from the pictures: An additional amplifier chassis, tube socket extenders, modifications of the chassis. But he does not mention in detail the added 6H6 double diode or the missing GW-42 transformers.

Nice! I was not so wrong with my interpretation of the chassis pictures...

But the fact that two people, Mike Buffington (a renowned RCA theremin expert) and me (not a renowned RCA theremin expert), make similar observations just from pictures does still not explain these modifications. One does not know for what reason they were made, which effect they make and by whom they were done. Actually the instrument looks relatively far away from the original circuit design which in my humble opinion rather reduces its value, at least as long as we don't know who did them. Some characteristic parts such as the GW-42 audio transformers are missing and can most probably not longer be found, so that a true restoration towards the original state seems to be rather impossible.

It might be that these modifications make sense though, especially if they were custom modifications done for example by Leon Theremin himself. In that case, a true expertise from Mike and Andy (not only from pictures) would be needed to prove their authenticity and their impact on the playability and sound of the instrument, which could probably increase its value.

Posted: 12/6/2013 1:32:57 AM

From: Eastleigh, Hampshire, U.K. ................................... Fred Mundell. ................................... Electronics Engineer. (Primarily Analogue) .. CV Synths 1974-1980 .. Theremin developer 2007 to present .. soon to be Developing / Trading as WaveCrafter.com . ...................................

Joined: 12/7/2007


""crackpot from France"

LOL ;-) ... Only marginally worse than  "Arrogant Retired European Engineers" that one TW member posted once on his website, then changed to "Engineer" when he wanted to brown-nose you, and switch the focus to his intended target, me!

At least he called me an engineer, not a clackpot - Clackpot is really clucking rude!



Posted: 12/6/2013 2:17:06 AM

From: Brooklyn,NY

Joined: 12/1/2009

Yeah, the thing is a total mess.   Mike told be about it and had shown me those photos a few weeks ago when he was visiting NY.  Would be a good candidate for a complete restoration- new cabinet and complete chassis tear-down.  Im pretty confident that it is salvageable( aside from the extra holes drilled into the chassis) but most i would pay is 1/5 the selling price.  Curiously though, I recon that if it was a straight-up  scammer it would be offered at a more realistic price, right?

btw...All the missing/ possibly damaged parts,  the PSU and the interstage audio txs are out there.   I found a 2nd gw-42 from an 'old parts' dealer online for about $10 when I built my Radiola 60-based replica. 

Posted: 12/6/2013 2:35:21 AM

From: Eastleigh, Hampshire, U.K. ................................... Fred Mundell. ................................... Electronics Engineer. (Primarily Analogue) .. CV Synths 1974-1980 .. Theremin developer 2007 to present .. soon to be Developing / Trading as WaveCrafter.com . ...................................

Joined: 12/7/2007

One thing I notice -

Its stated that S/N's start with 200.. this is 200 000 -

Is this perhaps a prototype? (or some form of pre-production model.. as in, the first actually released was maybe 200 001) ?

Also - the tube adaptors and "patching mods" could quite easily be deliberate and original if its a prototype ? - a sort of pre-production "breadboard" where final component selection was determined for given cabinet etc (real shame the cabinet isnt original) or where different transformers and tubes could be inserted to get things sounding right..

Or maybe it never had an original cabinet - perhaps it was just a workbench "experimentation" chassis which was later recovered and given flesh..

I want it! But I cant have it.. :-(


Posted: 12/6/2013 9:23:31 AM

From: Colmar, France

Joined: 12/31/2007

I don't think it's a prototype. If I remember well these instruments were built in two different factories, the one starting the serial numbers with 100... and the other with 200...

The modifications which we see, especially the removal of the UX-171 AF amplifier tube and addition of a separate audio amp chassis which looks much more modern (EL-34 or similar tubes in a push-pull configuration from what I can see on the pictures), seem to be from a later date than the production itself. Same thing for the 6H6 double diode which was only introduced in 1935 and has a "modern" octal socket.

Posted: 12/6/2013 7:33:06 PM

From: Brooklyn, New York

Joined: 11/25/2005

Though it looks like Bob has deleted his original posts (though they still showed up in my RSS feed) I can confirm that Bob has the said RCA, and that Andy and I have been in touch with him. My email to Bob that he posted just gave an overview and was an initial correspondence. Andy followed up with a more detailed observation of the modifications. 


Fred, the serial number is indeed curious. It's hard to determine if this is indeed the very first theremin (I had said earlier that I thought it was, but it may not be the case) but it is not a prototype, with respect to the modifications we can see and cabinet, at least. Thierry's right about the 6H6 and the other modifications, which were added at a much later date. The Hoffman-eque cabinet has parts from its original cabinet: the side rails where the chassis sits, and the sheet music shelf on the front.


Like Charlie, I think this could be returned to the original configuration, but would take a lot of work. I've got a perfect replica cabinet that I built that would make this a nice restoration job.


I have noticed that the theremin community here can appear to be a bit hostile when responding to people who have (or claim to have) and RCA Theremin for sale. There's good reason to be skeptical, since these instruments are hard to come by, and the seller might not be informed about what they have and the apparent/true value of the instrument. I've seen a lot of RCAs advertised here over the years. Some are sub-par restoration jobs that end up fetching a whopping price on eBay, while others that are in much better shape, though need some work (like the RCA that I bought), sold for much less. Then there are basket cases that some people on here have scoffed at and offered '200 bucks' for.


A few years ago this community unceremoniously removed a vulgar and rude man by the name of Billy who appeared to be trying to sell an RCA. Turns out he did have an RCA, confirmed with serial and door numbers. Don't know where the theremin is now, and don't have any way to get in touch.


Unfortunately, it's very hard to come by an RCA that's a good candidate for restoration that will be sold at a low enough price which, by the time one has put money in for electronics/hardware/cabinetry/finish, is justifiable. 


The key, when you're trying to sell anything of value, is how you present the item and yourself.

Posted: 12/8/2013 3:29:46 PM

From: Colmar, France

Joined: 12/31/2007

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