This small utility PCB mounts directly on to a standard 1-pole 12-way rotary switch (only 9 positions used) allowing you to replace the conventional COARSE TUNE pot in many VCO designs with an Octave or Footage selector.

The module provides up to 9 switched positions each providing a nominal 1V increment/decrement from the previous position and has a range of 0V to 8V. An Offset trimpot allows this range to be moved so that the module can provide 9 switched positions in the range -10V to +10V and thus allows the Octave Switcher to provide both negative and positive octave offsets such aas -4 Octaves to +4 Octaves.

Please note that this design uses surface-mount components (0805 and SO-8) and so requires some additional skill to assemble. I can supply these components pre-mounted on the PCB if required.

Octave Switcher Schematic Octave Switcher PCB Octave Switcher Bill of Materials