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.

 901B Oscillator PCBs are back in stock.

The latest PCB version has some minor changes:

- C100 (470uF) changes from axial to radial, as radial capacitors are more easily sourced.

- new option to use a 3 pin "turned pin" socket (half of a 6 pin socket) for the "selected" transistors T7 and T10.

The build document has been updated (V1-1).

 Two videos of my 901A Oscillator Controller with 901B Oscillators, with temporary panel. 

 

General overview (the scaling of the 901A is not optimum in this):

 

901A scaling following adjustment: