I've just completed building the (originally rare) Moog 901C output stage.
This amplifies standard Moog waveform levels for use as a deep modulation source, also generating positive-going and negative-going pulse waveforms. It has two complementary outputs.
As the original required a 3-pole 6-way switch, I've added electronic switching of the output waveforms, otherwise it's the original Moog circuit.
On the initial PCB run, the slots for the jack socket pins are not correctly cut, so I'm offering them at a reduced price (or free with 901A and 901B PCBs). The build document shows how to modify the PCB.
Works with my 901B oscillators, or with Behringer System 55 oscillator modules.
A trial panel is on order.