Based on an idea by Uwe Schüler at HomeMade Camp 2013. The RingModulator is a XOR-Gate built from two NAND-Gates (IC2B and IC2C on the schematics). For the case of at least one Square-Wave on the two input lines, a XOR-operation on the two signals equals a mulitplication of the two signals. For this special case, our XOR stage performs a ring modulation. We can now feed two square waves to the two input lines of the XOR-stage. These are produced with one NAND-gate for each wave (IC2A and IC2D). The output of the NAND gate is fed back to one input over a potentiometer (R3, R5) and with a capacitor to ground (C1, C2). The other input is attached to VCC. This circuit only needs four NAND-Gates - exactly what a 4093 IC provides. Adding two potis, two capacitors, six resistors (all of the same size) and a diode is all this very simple circuit needs to produce a wide range of interesting sounds!
Beginner SMD-version 2013
This version uses standard trough hole parts but with all of them soldered in pseudo-SMD on the boards' top layer. No drilling of PCBs needed and very easy soldering makes preparing workshops fast and relaxing. The picture below shows the placement of parts and the second picture is the mask for etching the boards.
- 1* 4093 IC
- 6* Resistors with same value in kOhm range (I've used 2.2k in the prototype, because i've just had 5 at hand, could be up to about 15k)
- 3* capacitors around 100nF (can also be 80, 120, 150, you don't have to use up all 100nF from the storage at any price ;-) )
- 2* Potentiometers in kOhm range (100k in the Prototype, also not critical)
- 1* Diode (just a normal one, doesn't matter much)
- 1* Battery Clip
- Piezo Speaker or Jack connector or both