The PAiA Theremax Theremin

Written 7/6/00, last revision 5/3/04

The Theremin was invented by Lev Sergievitch Termen, or as anglicised, LeonTheremin. It is one of the few truly original modern instruments. Many other forgotten electronic instruments used its heterodyning method of sound generation- for example, the Ondes Martenot. Its invention was simultaneously a new way of producing sound and a new way of articulating notes. It solves a problem for electronically driven acts by also being visually interesting. In my experience, audiences find the sight of someone playing a Theremin very intriguing. It’s also great fun!

I was bitten by the bug around 1990, but at the time there was no easy way to get your hands on a Theremin. There was Bob Moog’s Big Briar Etherwave. Adding all the optional
extra features to the Etherwave (especially the MIDI) makes it extremely expensive. Enter the PAiA. It doesn’t have MIDI as such, but, as we shall see, it does lots of things that the Etherwave doesn’t, as standard.

You may have heard of PAiA. They are probably the most successful supplier of electronics
kits in the world, having been in been in business since 1970. John Simonton, the brains behind the company, has always been interested in music and audio. Mark Vail considered him significant enough to dedicate a chapter to PAiA in his excellent book “Vintage Synthesisers”.

So I was delighted to discover that this company produced a Theremin kit, the 9505 Theremax. I made my purchase purely on the basis of what I had read of PAiA’s reputation, mostly on the Internet. People were saying that this was an excellent instrument, with a tone very close to the 1929 RCA Theremin, which is the one that featured in all those Hollywood B-movies. Quite a few Theremins are available these days,
as a quick search on the Internet will reveal. But the PAiA is among the cheapest, yet it is very highly rated among Theremin aficionados.

What it is:
The PAiA 9505 Theramax Theremin is a solid state instrument supplied as a kit. It is designed to play and sound like the classic RCA (valve) model designed by Leon Theremin himself. To quote the manual:

Theremax employs the same heterodyning principles as the original Theremins and produces the classic sound while adding embellishments made possible by the economy of transistors and integrated circuits.

It features control voltage outputs for volume, pitch and velocity (of which more later) and a gate/trigger output too, so it can be used as a controller for an analogue synthesiser. These features are expensive optional extras on the Etherwave.

Building it:
Anyone who’s methodical and good with a soldering iron should have no trouble with this kit. A deep knowledge of electronics is not required. The instructions are concise, and the board layout is very clear. If you’ve never built a circuit board before, you may find the joba little tedious, because there are over 100 components to solder in. A good 25 Watt soldering iron is a valuable investment for this job. Weller and Antex make good ones. In fact, a good soldering iron and a set of electronics tools is essential for any studio. A warning: if you’ve never touched a soldering iron in your life, don’t start out soldering with
this kit. Practice by making and repairing leads for your studio. That said, the instructions supplied with the kit offer very good, clear advice for the less experienced, including “tips from the pros”.

Make sure you start the work in a well lit room where construction will not be disturbed.
No kids or pets! Good ventilation is advisable, because the solder fumes are rather unpleasant. The manual advises that you solder in all the components in one sitting. This way you won’t loose track of anything. It took me about 2 hours. I didn’t rush it, took a few long breaks and it turned out to be quite a therapeutic exercise. The most difficult part is reading the resistor values. A colour coding system (industry standard) is used to denote the resistance, because the body of the resistor is too small to print numbers on. The manual provides a table of colours and values, but some people may have difficulty
telling the difference between maroon and red. A magnifying glass will save you strain here. The whole task is eased by the manual, which manages to provide foolproof instruction without being patronising. Wiring the pots into the board is also a little awkward, because there are lots of wires and the board is relatively small. If you find yourself going cross eyed, take a break!

The kit includes a 110v wall wart power supply. This is useless on this side of the pond, and
PAiA do not supply a 220v version. They included it in the kit anyway because it wasn’t economical for them to unpack it. That’s the attention to detail that keeps companies healthy. A standard variable power supply works fine instead, but make sure it is a regulated model capable of 12v@500mA. Unregualted ones will add 50Hz mains hum to your Theremin sound. Suitable PSUs are stocked by most hardware shops.

I decided to build my own case. Well actually, I got a carpenter friend to knock something up! This was very simple. I gave him the dimensions of the lectern case (downloaded from PAiA’s website) and he cut it from plywood. You could probably persuade your local DIY shop to do the same for you. The measurements are very accurate and should not cause any difficulty. The PAiA case is quite small, so light plywood (say eight millimeters thick) is the easiest thing to work with. Once this was nailed together it turned out to be very solid. PAiA point out that the Theremax can be built in to anything you like, from a shoebox to a sculpture. You could put yours into a mannequin like the Bonzo Dog Dooda band did in the sixties! The antennae are held on with butterfly screws, to allow you to dismantle them for transport. This makes it easy to create a left or right handed Theremin. There’s enough length in the antenna cable for this to work either way. For me this is another big advantage over the Etherwave, which as far as I know cannot be easily altered for southpaws. I would recommend that you purchase the front panel from PAiA. This is far easier than measuring out and drilling the holes for the sockets and knobs yourself, and it also looks really good.

The final step after assembly is to callibrate the oscillators. This could be an awkward procedure because it requires the adjustment of four inductors, which are not noted for
their stability. However the manual details the procedure very clearly, so a little patience is all that is required. It took me about 30 mintues to do this, and the achievement of a perfect Theremin tone was very satisfying!

On the PAiA website there are some tweaks and tips for the Theremin. I aded the “gimmick” coupling capacitor, which is very easy. It improves playability by reducing the lower range of the pitch.


As well as a sine wave tone, Theremax provides a square wave, which due to its rich harmonic content is useful for processing with outboard filters, or a synth with an audio input. The timbre knob allows you to choose between sine at one extreme and square at the other. Theremax has Control Voltage outputs for pitch and volume which will work with Volt/Octave or Hz/Volt synthesisers. It can be interesting to double the Theremin’s tone with an analogue synth- it gives bizarre and unpredictable “musical” intervals. I tested this with a Yamaha CS10 which is a Hz/Volt synth, and it gave me a useful pitch range. This reduced range has the advantage of being easier to play, but you sacrifice the true Theremin tone. A volt/octave synth should provide a much wider pitch range. The PAiA itself is capable of deep sub bass and almost supersonic highs in one swoop, so watch those speakers!

Because the Theremin has such a pure tone, most digital reverb units create a mush of sound. I recommend any Lexicon (obvious you might say!) or a Sony- I’ve used both. My preference really is for echo, the grungier the better. I’ve had best results with an analogue
delay unit. However a Theremin sounds especially good without any effects at all, as it’s tone can be reminiscent of the human voice, particularly in the high register where it can be most soprano-like. A good (Lexicon!) ambience setting can be useful here. Experiment with the LPF or high damping parameter on your reverb unit- a dull reverb is often best. Orchestration is very important. In the Theremin track on the music page, the simple Theremin melody is embellished nicely by the chords played with Mellotron and JJ Jeczalik sampled choirs.

According to Clara Rockmore, Theremin virtuoso, with the death of Leon Theremin, many of the more musically useful quirks of the original Theremin circuit design were lost, along
with his secrets for building and voicing theremins. A lot of research has been carried out over the years, and Bob Moog had some personal contact with Mr. Theremin shortly before he died. But having compared the two, I feel the Theremax has a more authentic tone than the Etherwave, and also allows more sonic variation. The Etherwave certainly has the aura of a more serious instrument, and has slightly more stable tuning. If you’re gigging the Theremax you must allow some time to set it up. On one occasion I found I had to go through the recalibration procedure about half an hour before an open air gig. I’m not sure if Theremax didn’t like the one hundred mile journey or the local electrical supply.

Considering the (pretty significant!) difference in price between Etherwave and Theremax, the PAiA is a remarkable instrument.

Playing it:

Theremin is probably one of the most difficult instruments to play, because you have to tactile feedback as you would with, say, a violin, which is probably its closest relative. So you need a very refined sense of pitch. Actually, playing Theremin is a good way to develop your sense of pitch. Clara Rockmore originally studied violin until a hand injury at an early age made this physically impossible. By chance she came across the Leon Theremin’s newly developed instrument, and adapted what she had learned. She developed many innovative techniques, such as aerial fingering, that allowed her to play rapid passages with legato or staccato articulation. In an interview in the 1970s, Rockmore lamented the fact that many people had come to her over the years to take lessons, but she had to turn them away because viable instruments (Leon Theremin oroginals) were not available. But most serious players agree that the current resurgence of interest has resulted in more musically useful Theremins being produced. The PAiA is certainly good enough to begin learning classical Theremin technique. It’s worth purchasing the tutorial video from the Big Briar website. You should also get to see Steve Martin’s film Theremin, an electronic Oddysey. It’s very moving to see what Theremin suffered at the hands of the KGB, and how close he and Clara still were, having been seperated for many years.

A Theremin will respond to any sort of movement within proximity, so position it carefully at gigs. Often performers just whoop it up, not hitting an exact pitch, just using it as a theatrical device. This can be great fun! Wayne Coyne of the Flaming Lips uses an Etherwave for this purpose in concert.

A foot switch input allows muting of the internal tone source without disabling the CV outputs. Switching with it causes an audible thumping sound, but it is useful when you
have no free hands. The Velocity Control Voltage lets you trigger notes on your synth according to how quickly you move your hand towards the volume antenna. Like everything else on a Theremin this is quite difficult to master, but you may prefer not to master it and leave the results to chance.

The front panel provide volume and pitch trim controls. These need to be set prior to a performance once the instrument has warmed up, and often during a performance as well. The pitch trim is set by keeping your hand away from the pitch antenna and adjusting
the output pitch so low as to be inaudible. However I often set this dial fully to the left, because it reduces the pitch range and makes it much easier to play tunes. When set this way the Theremax has a range of about 3 octaves, so it needs to be muted when not in use, otherwise it will produce a constant audible tone. The “gimmick” coupling capacitor also helps to reduce the range.

If you don’t have a problem with building it yourself, The Theremax is superb value for money when compared with the Big Briar instrument. It also has some nifty features that no other models have as standard, such as the comprehensive voltage control facilities. It is an easy kit to build, and with a little care you get a superb instrument. This is a serious Theremin at a very non-serious price.

Links (NB: check out our review of
Theremin websites

Check out the very illuminating technical article on Theremin tone by John Simonton.

Bob Moogs company. They also sell videos, CDs and “minimugs”! CDs by Theremin virtuosos Lydia Kavina Clara Rockmore available, as well as an instructional video by Lydia and a documentary of Clara Rockmore.

Interesting electronic music site with good article on Theremin playing and links to other sites.
History of Electronic Musical Instruments. Quite comprehensive, and count all the other instruments that used Theremin’s heterodyning to generate their sound!

British company Longwave, who make a solid state Theremin also based on the RCA valve classic, as well as a pocket Theremin.

The Theremin web ring. There’s a very interesting interview buried in there with the man who played on the Beach Boys “Good Vibrations”. It seems it wasn’t really a Theremin…

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