This version was constructed using rotary switches, primarily for the ease of panel cutouts. Using a 6 position rotary switch for the ratio selector meant that another two compression settings, 6:1 and 10:1 could be included. Adding these settings meant that a new PCB for the rotary switch and its resistor chain was needed. In order to fit all the resistors and not foul other panel mounted components, both rotary switches (ratio and metering) were included on the one PCB, spaced apart by 1.380" (35mm).
There are two versions of the switch module, the only difference is the rotation of the switches. This allowed an alternative knob with an offset grub screw to be used and still line up with the panel markings.
The original component designators and interconnection point references have been retained. The new resistors are designated in the 90's (R90, 92, 93, 94, 95, 97, 98, 99). The PCB and circuit are available in the accompanying PDF links. The assembled PCB is shown below.
The switch module has an optional resistor marked RT on it. This resistor can be selected during testing to set the desired threshold at which compression starts.
It should be noted that the switches are mounted on the back side of the PCB and the other components and wiring attachment points are accessible on the top side of the PCB.
|CSM-1 Circuit (pdf)|
|CSM-1 K1 version PCB (pdf)||CSM-1 PCB K2 version (pdf)|
The switch module provides for the connection of the following panel components to it:
- Attck pot
- GR disable switch (on the attack pot)
- Release pot
- Output pot
- VU Meter
- Ratio switch (6-way)
- Metering switch (3-way)
Switch module front and back views