This sits just to the right of Quantisise to provide some timbre enhancements, mixing, processing, and output capability, so that a performance might need to use only the one rack. I selected timbre enhancing circuits that work well with triangle waves, to match the Quantisise outputs. It contains:
- Two Wave Multipliers
- Two CGS Tube VCAs
- A CGS Active Real Ring Modulator
- A 4-to-2 matrix mixer
- A 4-to-4 matrix mixer
- Two DC processors
- Two output channels
Wave Multipliers
These are second and third wave multipliers from the CGS113 Serge Wave Multipliers. It’s my second build of Ken’s board. Happily, Rev 1.1 of the board fixed some issues and added holes for the 47pf caps, so they don’t have to be soldered to the back now. I omitted the first multiplier for panel space reasons and because it’s not as spectacular sounding as the other two. Panel space being limited, I have only one input (yellow), CV input (blue), one output (green), and the Initial pot for these.
Tube VCAs
The CGS65 VCA/Timbral Gate is fantastic for enhancing timber. I already had built two in MOTM format. Again for space reasons, each has only an input, output and CV jack. A matrix mixer added on the input or CV input will yield any needed additional attenuation.
Active Real Ring Modulator
The CGS67 PC Board is used here. My version omits the guitar preamp, but has both AC and DC inputs for the carrier, plus for pots. This is the first time I’ve built the ARRM.
Matrix Mixers
My friend David Linton suggested matrix mixers for use with the Quantisise. And here they are! CGS81 boards are employed to implement. (See schematic, below.) I decided on two separate matrices, a 4-to-2 and a 4-to-4. Each input (yellow jack) is buffered and sent to a column of pots (2 or 4). A row of pots is mixed for each output (green jack). Note that the signal is inverted at the pots, but back to normal at the outputs.
DC Voltage Processors
Two single-channel processors are also made with CGS81 boards. In this design, the input is level-controlled through a pot and mixed with a DC bias from another pot. Normal and inverted outputs are provided simultaneously. I decided against having the level pot be able to reverse the signal (left or right of center), because I like to be able to shut off a signal completely, which doesn’t work with the center-off approach.
Output Channels
Two output channels (Left and Right) simply mix together two inputs each and provide a gain control. I designed it for 50% gain to reduce the hotness of the signal a little. A CGS81 Voltage Processor board is used. See the schematic, below. The output are 1/4-inch jacks for patching to line level equipment.
Block Diagram
Schematic for CGS81 Circuits
