This page should be of some help to those building the University of Glasgow's digital theremin design. As I complete my own version of the project, I will post my experiences and tips, and hopefully some pictures when all is said and done. If you have built this theremin and have tips of your own to add, please e-mail them and I'll add them to this page.

Schematic FAQs

Lots of questions come in regarding the digital theremin schematic and some of the notation used. Hopefully this will help clear some things up. Some of these questions don't have answers yet because I haven't finished building my digital theremin. If you've already tackled this project and have some tips or comments, please send e-mail.

1. Updated Schematic Available! - A fellow Levnetter has sent in this updated drawing of the digital theremin schematic. It corrects a few mistakes and omissions in the originally circuit. Before you start building, be sure to take a look at this circuit.

2. In the pitch antenna section, what should the top-left 22pF capacitor be connected to ? - It should be connected between pin 1 of the 4093 chip and ground, just like the one below it in the schematic.

3. Which of the several potentiometers are exposed on the front panel? - According to K. Skeldon of the Univ. of Glasgow, the 10K potentiometers in the TLE-2027 amplifier section (in series with the 10K fixed resistors) are exposed to the player. The others are simple trimmer pots used for infrequent tuning. In my version of this digital theremin, I'm exposing a couple of extra pots. The data sheet for the 8038 VCO indicates that the waveform can be shaped by using a slightly different VCO layout. This circuit involves 2 potentiometers and can make the wave a little more lop-sided, like the RCA waveform.

4. In the final amplifier section, what are the R's on the resistor values (e.g. 100R)? - This means Ohm. 100R = 100 Ohms.

5. Zener Diode is drawn incorrectly - Be aware that the "2V7" diode should be symbolized as a Zener, with the cathode up, not down, as shown. (It is a 2.7 volt Zener diode.) Thanks to Art Harrison for this tip!

6. What types of antennas should I use? - You can use the telescoping radio-type antennas showed in the pictures at the Glasgow site. You can also make your antennas out of nickle-plated brass or copper tubing, available in the plumbing section of most hardware stores. This bends easily and has great electrical characteristics.

7. When I adjust the pitch antenna, the volume circuit doesn't respond well, and vice versa - Fellow Levnetter Max Baars (see his great site at www.maxiespages.com had this to say.