A simple triangle-core VCO module that uses a CD40106, CD4066, LM358, a few transistors, and passive components.
Features:
- FM modulation
- Hard sync
- Exponential (not v/Oct) pitch tracking
- Simple, hackable design
This design is based off of electro-music.com user Synaesthesia's Triangle VCO with gate. In place of the original's NAND, I've opted to use a NOT gate. This does away with the gate functionality, as I'd like to use this with a more traditional VCA, and I have an abundance of 40106 chips.
Additionally, I've added an output buffer, crossmod, and hard sync. I have decided to not have a square output, and dedicated hard sync input jack, but these can be easily added in.
If you plan on building this using my perfboard layout, I'd highly recommend using the schematic as a reference. Not everything is mounted on the board, so you'll want to pay attention to things like the crossmod and hard sync connections.
Note that the colored nodes are supposed to be connected to points on the other oscillator. For example, the dark blue "to osc B" node, should be connected to oscillator B's equivalent to the dark blue "from osc B" node.
I've implemented this circuit on double-sided perfboard, which I found to be the easiest and most size efficient medium. I made heavy use of both sides of the board, in addition to having "floating" wires, sometimes using 0 ohm resistors, out of convenience. I represented some of these floating wires as thin, curvy traces in my diagrams.
AS OF RIGHT NOW I AM STILL WORKING ON THE DIAGRAMS... STAY TUNED.