Here is a wide range, non-precision, and somewhat unstable voltage-controlled oscillator (VCO) with just a pot for initial frequency, a CV input attenuator, a triangle (-0.5 to +4.5 volts) and a square wave (+/-14.3 volts). It uses an obsolete part (CA3080). Perfect for the Quantisise!
This CGS SSG board is built as a dual VCO for the Quantisise, which uses three of these boards. The Serge SSG consists of two virtually identical voltage-controlled slewing circuits that, depending on how patched, can function as a straight-through slew, an LFO/VCO, or a Sample & Hold. I also used this board in the CGS-Serge panel to make a true SSG. Here, the two circuits are each hard-wired to cycle as a VCO. This schematic shows one of the circuits, as built, plus a bit of wiring for an unused section of the LM3900. (Ignore the LED driver.)
There’s no external input. The parts for the one-shot circuits and the hold inputs are omitted. A jumper from pin 5 of the cycle comparator back to the input (A, K) patches the feedback that makes it oscillate. I’m using the same 47 nf capacitor as I used in the Quantisise S&H as the integrator. This gives a maximum frequency in the 3.5 Khz range. The low end is as low as you need, virtually stopping. Much of this range can be swept by a 5-volt CV. The Cycle Out will be patched to a One Shot input on a S&H board and optionally routed to S&H Hold inputs by toggle switches on the Quantisise control panel.