Dual LFO/VCO

Upgraded version of the NLC dual LFO / dual VCO

This is an upgrade for the NLC thru-hole dual LFO and the thru-hole dual VCO.
The circuit is based on the thru-hole dual VCO but can be switched to operate in 3 ranges; 15Hz-10kHz, 1 minute per cycle to 25Hz (approx) and down to 20 minutes per cycle for the slowest.

Both have CV inputs with attenuating pots and sync inputs. The sync is quite hard and attempts to momentarily ground the timing capacitor, how successful this is depends on what else is going on. At slow LFO rates it works more like a wave-shaper.

The outputs are sine, stepped, square and triangle. The stepped outputs are S&H circuits sampling the sine-waves. They are clocked by the other oscillator, there is no external clock input :)

There is provision to install 1k tempco resistors if you want to try for 1V/oct tracking. Don't expect good tracking over more than 2 octaves though, there are no matched transistors onboard. If such niceties are not so important, simply leave off the 1k tempcos and install regular 1k 0805 resistors on the bottom of the engine PCB.

https://www.nonlinearcircuits.com/modules/p/dual-lfo