Build a Theremin with Tubes Like Leon Did a Century Ago

When Leon Theremin built his now famous musical instrument, he only had valves at his disposition. Today we have the choice between analog and digital techniques, and between BJTs, FETs, and valves. We can even combine them all. This special 99th-anniversary version Theremin design only uses valves.

Invented about one hundred years ago the Theremin remains a popular electronic musical instrument. Commercially available high-quality designs are expensive making DIY projects extra appealing. However, it is not so easy to come up with a reproducible all-analogue circuit. Can you help?

You think a CRT oscilloscope, 100% analog, is not made for “looking at music”? Well, you’re wrong: here a good old oscilloscope draws elegant animated geometric images on its screen, synchronized with music specially created for this. It’s the well-known principle of Lissajous figures, elevated here to the realms of art, matched with an amazing soundtrack. Fascinating!

Among the starter kits offered by Elektor, there are very few which are dedicated to sound production, an area of electronics which is developing rapidly. The mini synthesizer kit examined here is a product from the big German publisher Franzis, specialising in publications on electronics applications and micro computing. This full kit, partially assembled, comes with case, keyboard and loudspeaker. How do they do it for this price?

In a series of videos, Marco Reps invites you to follow his Elektor Formant Modular Synthesizer Overhaul. His opening commitment says 'I'm gonna refurbish this old electronic music instrument in several episodes'. Six have been published so far. While reconditioning, repairing, rebuilding and even redesigning, Marco recounts the resurrection of his almost 30 years old analog synthesizer.

The project that we highlight this week concerns a subject that we encounter every once in a while: an electronic wind instrument. Based on a PIC32 this device lets you control a music synthesizer over MIDI by blowing in it, just like a flute. Unlike a flute, or any other wind instrument for that matter, this one can also be played without blowing at all. Also the fingering has been simplified because there are no physical constraints on the position of the keys.

A month ago, in his review, my colleague Thijs Beckers was extolling the virtues of the assembled synthesiser module J²B, but he didn’t tell you everything. From my point of view, he even forgot the essentials, to know what comes out of the synthesiser and enters in our ears! We need to revisit this subject, especially because in the description of the synthesiser already published by Elektor, it was only a question of…..software.

The tendency to use obscure terminology for the functions of new synthesiser modules does not always make them accessible. On the other hand, the facade of a module with apparently trivial functions can hide literally unheard resources, for example in the case of the Tea Kick (entirely assembled by hand in Brno by the Czech constructor Bastl).

Among the trends in products presented at the recent 2016 NAMM show, we’ve already remarked on the widespread use of the word “Analog”. Another key-word seen everywhere is “Modular”. Lots of new Synthesisers, even those which are basically digital, are modular, with lots of buttons, swtiches and inputs and outputs connected between themselves with a rats-nest of cables.

The slogan “The Music Begins Here” is that of the NAMM Show; it is one of the most important US Trade shows, which is held at the beginning of the year, and presents new products, usually available at retail a few months later. This year, the fashion is Analog, a ticket that sells!