1.9 KiB
ZOE - Simple Saw VCO
This is a simple saw-wave generator VCO that features 1/v per octave functionality. This inital version is almost an exact rip-off of this VCO https://www.youtube.com/watch?v=rq4ovZ2om6k, which itself is a modified version of Ray Wilson's VCO: https://www.soundtronics.co.uk/Datasheets/7210-001-VCO.pdf. The 2nd version is based off the saw-wave oscillator base of Jim Patchel's VCO (http://www.noniandjim.com/Jim/synthmodulesII/200-1007.pdf), with some modifications to remove obsolete or difficult to source parts.
Revision List
Rev 1.0 - March 2021
- Exact copy of the VCO by vk2seb on youtube
Rev 1.1 - April 2021
- Started redrawing the schematic based on internal EAGLE blocks with multi-part compnents rather than the blocks from libraries.
- Never finished
Rev 2.0 - December 2021
- Redrew the VCO based on Jim Patchel's design, which is very similar but:
- Uses an MAT04 (I use a MAT14 instead), as opposed to a LM3046. Both are obsolete but a replacement for the MAT04 is available.
- Heat/Temperature compensation via LM13700 OTAs which feed the linear to exponential converter (much better performance expected)
- Oscillator is based around an N-channel JFET instead of several BJTs and op-amps (better performance expected).
- Elimination of several components due to simplification of the overall design
TODO list/future features:
For a more complete list, please see the projects page
- Proper labels for all the potentiometers
- ZOE interface (the large 50-pin ribbon connector I like)
- Bill of Materials
- Documentation on how the oscillator actually works.
Notes:
This VCO conforms to the dimesnions of a Eurocard (100mm x 100mm).
By extension, it conforms to the Eurorack modular synthsizor convention, where the PCB is inside the rack and the connectors are sticking out the front. Due to this layout, the VCO could either be a 1u or 2u module depending on how you want to connect the panel components.