You can't have a synth, modular or otherwise, without oscillators! But why have one when you can have four? This is a slight twist on the popular 40106 oscilator bank, with very simple CV control of the oscillators added with diodes. Very low parts count, a nice easy build.
In the article we cover why it oscillates, as well as why the diode allows for pitch control and gating. On top of that, we figure out how to calculate the pitch of the oscillators and how to figure out where the gating effect of the diode kicks in.