Table of Contents


Fabrication Info

DifficultyRating: 6 / 10

Components 61
Resistors 34, 2 Thermistors
Capacitors 3 Electrolytic, 4 Polyester
Diodes 3
Transistors 8
ICs 3
Other 1 Pot, 1 Switch, 2 Trim Pots

Be careful, there are 4 different kinds of transistors on this circuit. Make sure you get the right one in the right place. After you build the VCO, it is a good idea to Test the circuit after you build it, this will make tesitng (and troubleshooting, if you have to) the other sections much easier.


You might want to mount Q8 on a SipSocket, so that you can put a HighGainTransistor in there.

If you are unsure of your soldering skills, you can also mount the 3 ICs on DipSockets. Also, if in the future one of these ICs were to fail, you will be glad you socketed them!

According to the build manual when the sawtooth and squarewave are tested, R36 is not yet soldered in, but on the fotos it is there. It's a good idea to have R36 soldered when testing to get the correct waveforms and DC bias.

Mistakes to avoid

equaliser says… The picture in the fab manual for the 2SK30AO transistor is actually of the AY transistor, which I soldered instead of the AO. Ignore the pic - you need the AO in the VCO.