DEMO Theremin kit (not a pedal)

This post contains an audio or video demo

DAJE

Well-known member
Build Rating
3.00 star(s)
I bought the kit before Xmas, and finally got around to putting it together. It's from Jaycar, who are the sole surviving electronics hobbyist place (ie Radio Shack) in Australia and possibly New Zealand.

Jaycar are expensive but it's handy to be able to drop in and grab some capacitors or whatever off the shelf. And they're quite good for some things, like IPA. They also have kits, including this one, which is an upgraded version of the Theremin kits that they've been selling for decades...

So, observations: I like the fact that the PCB is well laid out and easy to work on. Clearly marked with component values etc. As you can see, a couple of the trannies are bolted on to the PCB and the voltage regulator is bolted onto the PCB via a heatsink. That's fun. There are pages of extensive build notes and everything is nicely documented. There are 18 test points on the PCB for checking voltages, along with a list of what you should be seeing (and my readings are all in the ballpark).

The components are mostly decent, though Jaycar do not care about mojo or ceramic caps in the audio path. I did consider upgrading to MLCC but in the end I just went with what they supplied. I added a couple of items to enable a 6.35mm socket for output to an amp. Annoyingly, there's no output if you disconnect the built-in mini speaker. There's probably a simple way to fix that but I'd need someone who understands this stuff properly to explain it to me.

There are a couple of radio wheel adjustment things for pitch and volume, both of which are dodgy as all get out. There's no effective way to tune the thing, and the volume is either on or off when the wheel does anything at all. So, it's really a toy. Cool and fun, but not usable as a musical instrument. Which is sad because I really like the idea of making music with a theremin and I feel that I'd be able to do that with something a bit better designed.

I haven't boxed it because the plastic box is not just ugly but needs to be modified to actually fit the PCB. Also, it's built for a 9VAC (not DC) power supply, which I happened to have one of, but that'd add a bit more expense if you needed one. Plus the AC socket is a weird 2.5mm (not effect pedal standard 2.1mm) socket, which I also happened to have an adaptor for.

A proper theremin would be expensive. The Jaycar one could probably be improved by someone who knew what they were doing, but for me I'm kind of stuck with this, and I don't think it could be improved enough to make it musically useful as an instrument anyway.

Anyway, here's a brief demo, this is about as good as it gets.
 

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Pretty nifty!

The diy world really does need some good theremin options though— the moog kit was a bit disappointing in the sense that everything was pre-populated, and really more of just an “assemble these three connections”, plus it’s been discontinued for ages. The zeppelin labs kit isn’t really a theremin at all. The PAiA kit is the most legit option, but it’s known to have a pretty lackluster tone, and not be super useable for performance. The rest of the diy options out there are toyish theremin-esque objects with only a pitch antenna and a volume knob, and fit in a roughly 1590B sized enclosure— more like the one Jimmy page used for sound effects, and not something you could ever actually play a melody with pitch and dynamics on
 
I never thought of the Zep Labs Altura as a Theremin but as a synth-MIDI controller device that I wanted.
I see now it's marketed as a Theremin, too. Funny how that marketing never registered in my brain at all.

Still want it.

You're on point with all comments, Nick: Moog, Zep, PAiA, and toys. I would love to have a proper DIY Theremin.
 
I never thought of the Zep Labs Altura as a Theremin but as a synth-MIDI controller device that I wanted.
I see now it's marketed as a Theremin, too. Funny how that marketing never registered in my brain at all.

Still want it.
Same! Especially now that it’s the v2 with the bent steel case instead of a folded cardstock or puzzlepieced acrylic case. Would be a ton of fun to add to my synth rig.
You're on point with all comments, Nick: Moog, Zep, PAiA, and toys. I would love to have a proper DIY Theremin.
If @Robert wants to trace a claravox, I’d be more than happy to create woodworking plans for the enclosure part of the project ;)
 
Open source theremin project. Gerber files are on Github (linked on project page)


Looks like a bunch of SMD, but we can do it.
 
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