1968 SWTPC Theremin - looking for any info

Hello everyone, I'm a long time lurker and new member here. I just purchased an Etherwave Standard and a Lost Volts LV-4 as my first theremins. 

The reason I even got interested in the theremin is that my father recently gave me a theremin he was gifted by his sister's boyfriend in college. Here's the information I was able to gather about it from some research:

1968 SWTPC Theremin Kit
- Manufacturer: Southwest Technical Products Corporation (SWTPC), San Antonio, TX. 
- Connection: HemisFair '68 (World’s Fair), October 6, 1968. 
- Design: 
  - DIY kit with a wooden enclosure. 
  - 14.5” x 7” x 3”. 
  - Battery-powered (9V). 
  - 1/4-inch audio output for amplifier or speaker. 
  - Controls: Pitch knob, Volume knob, On/Off switch. 
- Circuitry: 
  - Analog design with inductors and discrete components. 
  - Red inductors (coils) for pitch/volume heterodyning. 
  - Minimalist design for hobbyist assembly. 
- Condition: 
  - Wooden case and components intact; minor wear. 
  - Likely needs restoration (e.g., replacing capacitors) for full functionality. 
- Significance: 
  - Rare collectible tied to the 1960s DIY electronics movement and theremin revival. 
  - Represents innovation showcased at HemisFair '68. 
- Value: Historical artifact or playable theremin after restoration. 

He still had the original box stored in his basement, and upon looking at it I can clearly see the address it came from:

Southwest Tech Prod Corp.
219 W. Rhapsody
San Antonio, Texas 76218

And that it either was purchased and/or came from the HemisFair '68 (World’s Fair), October 6, 1968.

I took photos of the theremin and the box it came in which you can see here: 1968 SWTPC Theremin

I'm curious if anyone has any information about this theremin besides the links I found online:

https://deramp.com/swtpc.com/History/SWTPC_History.htm

https://www.theremin.us/144/144.htm

https://en.wikipedia.org/wiki/HemisFair_'68

I plan on putting this theremin into a case and making sure to protect the box also as it adds the provenance to it.

Hello jsherm, this is a fine theremin with all the electronics required to make a usable instrument. The triangular antennas certainly go well with the hand capacitance. But they are probably too close together, so that volume and pitch influence each other. You can test it with the amplifier (any high-impedance guitar amplifier with input level control would also be suitable).

I found the following files on the Internet:

Manual with the circuit diagram and all components: https://wiki.theretrowagon.com/w/images/6/6c/SWTP-ThereminManual.pdf

Sales brochure: https://www.wass.net/othermanuals/SWTPC.pdf

Popular Electronics 1967: https://www.worldradiohistory.com/Archive-Poptronics/60s/67/Pop-1967-11.pdf

I am curious to see how your first Theremin experiences will go.

JPascal

Wow JPascal! Thank you for sending those links, I don't think I would have ever found them. My dad will be very happy to see them also - as the theremin was his originally.  I did plug it into an amp but couldn't seem to get it to work. I'll try it again sometime. I'm sure it needs to be fixed.

I'm excited to start learning to play my Etherwave (it will arrive next week), I believe it's from the original production run since the serial # is 22,113. I do understand that it's not the Pro or the Plus, and that it won't have the ESPE01 mod installed. Especially since the person I bought it from never used it, and stated that it was factory sealed brand new. 

Before I bought the Etherwave, I had ordered the Lostvolts LV-4 from John in the UK since I didn't know I was getting the Etherwave (they are very difficult to find - and I feel like I got super lucky finding a new one). I'm told by a lot of people who have the LV-4 that they prefer it to the EW. So I will be very curious to find out which one I like more!

Today I bought a Behringer K450FX Ultratone amp (based on Thierry's many recommendations I saw on here) from a woman who never used it. She bought it in 2020 to learn how to play the theremin but never got the hang of it and had no use for it. It was brand new! Quite a coincidence.

So now I just await my theremins which should both be here next week. I'm told that since I'm a classically trained violinist, I should have a much better experience than most people who don't have any prior instrument training. We will see soon enough

As a trained violinist, it will surely be easier for you to coordinate the two hands for volume and pitch. Most beginners have difficulty coordinating both hands independently. Then the annoying “weeuuuh-weehuuuh” immediately destroys the magic of the instrument. The absence of frets on a violin is also an advantage. As a right-hander, however, the bow hand would be more obvious for the volume, but the theremin has the volume on the left, unless you play it from the back. But this is a bit sophisticated and your choice will be rigth.

Your test of both instruments will be exciting and I am looking forward for it. 

Yes JPascal, I agree! I am quite curious to find out if the "hand switch" will be tough to overcome. In preparation I've been watching Clara Rockmore and Caroline Eyck videos to practice the hand positions in the meantime, and I believe I will get used to the hand switch. I'm not sure if I want to stick to the strict hand positions just yet, as I'd like to explore my own feeling of the instrument first - I assume that's part of the fun!

I do love a good glissando on the violin, and am eager to also perform some staccato notes with my left hand. I already have some ideas for techniques I'd like to try with my hands and fingers, and am quite curious to find out if they will work on a theremin. I did think about playing from the back to make it easier for my muscle memory to pick it up quickly since I'm already used to pitch on the left and volume on the right, but I like a challenge, and I'd rather play the instrument the way in which it was designed.

If and when I get good enough, I plan on shooting some videos to post online from my music studio. And I promised John at Lost Volts I'd make a proper video review of the LV-4 since there aren't any (I was shocked!). I'll post any and all videos in this forum when I create them. In the meantime, I'm eager to play both the original Etherwave Standard, and the LV-4 - and see what differences they have in playability. I am beyond thrilled to have found a supportive community here!