993 Trigger & Env Voltages

AMSynths 993 Panel

Introduction In August 2020 I bought a set of Behringer System 55 modules, as my first journey into Moog modular. My plan is to recreate the Klaus Schulze IIIP synthesizer and Dual Sequencer setup that Klaus bought on 22nd December 1975, and used successfully for many years.

Whilst the Behringer modules cover most of the Moog modules I need, there are a few additional modules I need to recreate, like the 993 from the IIIP.

AMSynths 993 Module This is a replica of the original Moog design but without the colour illuminated slide switches. Even Moog could not find these when they re-issued the System 55 and had to have them 3D printed. I have used black DPDT slide switches, which switch on the circuits as well as an indicator LED.

I have used red LED’s for the Trigger Inputs, yellow LED’s for the trigger routing, and green LED’s for the 911 to 902 routing. They are cylindrical LED’s mounted on standoffs, which match the Behringer SMD LED’s. I did experiment with white LED’s but they were not truly diffused and had a center bright area.

AMSynths 993 Module

The AM993 PCB has a 12V power inlet socket, eight slide switches and LED’s. Rather than hand wiring to each jack socket, I have used a more robust cabling system that uses Molex “latching” 2 and 3 pin connectors. There is a small daughter PCB that attaches to the back of each of the 902, 911A and 911 modules.

Molex connectors are used to provided the inter module cabling, with wires soldered to the various Behringer jack sockets from the daughter PCB’s. The jack sockets are not normalised, so no PCB traces need to be cut on the Behringer modules.

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