This synthesizer took me about a year to make. I spent as much time making it look beautiful as I did on the electronics. It is an improved version of a previous synthesizer, The Machine. The main improvement I made is that this one is a lot more reliable. I had so many problems with the other one breaking down on stage. This one hardly ever goes wrong. Another feature is all the coloured lights, they let me know what switches I have switched on. This is very useful on stage when you need to change from one sound to another very quickly.
A Lovely diagram of what the knobs do
It has 2 ribbon-controllers so you can play 2 different notes at once, but this is a skill I have not yet mastered. The ribbon controllers are wire wound variable resistors the wire is 1 tenth of a mm, very fine, over 6000 turns. It is wound onto plastic rods, the resistance it about 10k.
Playing with a ribbon gives you a similar sound to a theremin, except it is a lot easier to play in tune because you can see the notes marked out along the ribbon. I prefer the sound of a ribbon over the sound of a keyboard with portamento. The problem with portamento is that you can't time when you glide into the notes only when you glide out of them. Portamento sounds more kitsch to me than a ribbon controller.
I play the ribbon with 2 sharpened toothbrushes, one in each hand. I find the plastic on cheap toothbrushes slides well on the metal. I have only recently mastered the 2 toothbrush technique. It is very expressive because you can use a combination of slides and keyboard style jumps.
This synthesizer is modular, the patch bay is 2.5mm jacks. There is a switch to change it to internally patched. I used miniature relays to do this. The internal patch is what I use on stage.
I have made an old fashioned diode ring modulator. This is a simple circuit using germanium diodes and LT44 output transformers. I prefer the sound of this type of ring modulator over modern designs using multiplier chips. It is normally described as a passive circuit, but I have used buffer amplifiers on the inputs. I found you get a better sound if you get the signal levels just right on the inputs. In the first sound I am blending between normal and ring-modRINGMOD.WAV
Here is a picture of the valve distortion circuit. As I have very little space I decided to use a miniature nuvistor valve. It is a class A triode circuit which means very soft distortion and lots of 2nd harmonics because of the way it squashes the wave asymmetrically.DISTORTION1.WAV