Gatekeeper

Every Keymaster needs a Gatekeeper–this is the Zuul to our Vinz Clortho.

Utilizing three CD4029 up/down counters, Gatekeeper provides rhythmic gate patterns in a variety of configurations. Inputs are normalled to the gate outputs of the Keymaster module to allow for ease-of-patching. Channels B and C of the Gatekeeper can be normalled either to their Keymaster counterpart, or to whatever is at the input of Channel A.

All three channels can be controlled independently from Keymaster with independent inputs. Channel A rhythm can be toggled between a binary and decade count mode*. Channel B can be set to carry over from Channel A (Channel B count increments only after each cycle of Channel A). Channel C can be set to carry over from Channel B (Channel C count incre… You get the point).

This allows for extremely long gates that can be combined with extremely long slews to generate very long, synced triangle or trapezoid waveforms.

*Binary mode should cycle through 16 states before resetting. Decade mode should cycle through 10 states. But, if we’re being honest, we never sat down and counted.

Schematic

As with any schematic found on the internet, exercise caution when building. Test the build before plugging it into your case. If you find mistakes in the schematic, or you have recommendations for improving the design, feel free to contact us and let us know.

BOM

Components for the output stage will be marked with an ** and should be multiplied by the number of channels used in your build.

• Resistors
  • 1k (1) R7**
  • 3.9k* (1) R4**
  • 6.8k (1) R6**
  • 9.1k (1) R5**
  • 100k (3) R1, R2, R3
• ICs
  • CD4029 (3) U1, U2, U3
  • TL074 (1) U4
• LEDs (1) D1**
• Audio jacks (1) J4**
• Switched audio jacks (3) J1, J2, J3
• SPDT (5) SW1, SW2, SW3, SW4, SW5

Demo

Coming eventually