◊ PCB Documentation

111 Ring Modulator

All-discrete ring mod based on the one half of the Buchla 111 circuit. Note: original 111 was a dual; this PCB is for a single ring modulator, so you would need two for a clone project. Adapted from PCB design by vtl5c3.

PCBs are $15.00 @ — ORDER HERE

Bill of Materials (value/qty)

  • Resistors
    • 10r x2 *
    • 10k x2
    • 100k x2
    • 1k5 x4
    • 220r x2
    • 2k2 x1
    • 22k x1
    • 330r x2
    • 3k3 x5
    • 33k x1
    • 47r x3
    • 680r x6 x5
    • 6k8 x4
    • 680k x1 *
    • RA 22k x2 (optional input attenuators)
    • RB 1k x2 (optional input attenuators)
  • Capacitors
    • 2n2 x2
    • 0.1uf x1
    • 4.7uf x2
    • 5.6uf x2 *
    • 10uf x1
  • Transistors
    • 2n3904 x7
    • 2n3906 x3
  • Misc.
    • .100" 4-pin power header x1
    • ferrite bead x1


  • On the schematic, R38 (47Ω) is shown tied from Q8 to several of the other transistors; it should instead be tied from Q8 to V+. This correction is made on our PCB.
  • The polarized 5.6uf caps by the outputs are shown as 56uf on the schematic; 5.6uf is believed to be correct.
  • Based on examination of an actual unit, Apetechnology reports that R27 (given as 680Ω on the schematic) should instead be 680k. (see image below)
  • R14 on our PCB is incorrectly marked as 10r; it should instead be 10k. Thanks to Mike Peake for pointing out this error. (see image below)

Marked 680Ω on PCB, substitute 680k

Marked 10Ω on PCB, substitute 10k


    The text, images, graphics, and other content of this website related to Don Buchla's legacy synthesizer designs is made available under the Fair Use Doctrine of the US Copyright Office. Fair Use limits the use of this information to personal, educational, and scholarly purposes (including right-to-repair, where applicable). It may not be used as the basis of commercial or for-profit works. Our Printed Circuit Boards may be purchased and assembled for your personal or educational use, but may not be manufactured and sold as "Buchla" products.