Enter the noise!

4Square is a nasty little box of fun built around a 4093 quad NAND Schmitt Trigger circuit. Four independent square-wave oscillators pinging off of one another to create complex sounds–metallic FM sounds, stepped square waves, classic video game bleeps and bloops.

Mix control over each oscillator allows you to dial in the desired mix of each sound. Solo output for oscillator one for creative self-patching, or controlling an external modulation source. Vactrol-based CV over oscillators 2 and 4, and a passive VCA to shape the output signal with an envelope or LFO.

4Square is not a precision oscillator and does not track 1v/octave.


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.


  • Capacitors*
    • 0.1uf (1) C4
    • 0.47uf (1) C3
    • 1uf (2) C2, C5
    • 4.7UF (1) C1
  • Resistors
    • 1k (12) R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, R13
    • 20k** (1) R12
  • Potentiometers
    • 50k (3) RV2, RV3, RV4
    • 100k (1) RV1
  • ICs
    • CD4093 (1) U1
    • TL074 (1) U4
  • LED (1) D1
  • Audio jacks (4) J1, J2, J3, J5
  • Switched audio jacks (1) J4
  • 2n7000 FET transistor (1) Q1
  • VTL5C vactrols (2) U2, U3

*These are recommended values for four oscillators of different ranges. Experiment and find the values that suit your tastes
**We got a batch of extremely bright LEDs and the unusually high resistance value here is to help bring it back to a comfortable level–your LED might need a smaller resistor value