The Zonk PCB features my own layout design with 3 methods for building a Zonk Machine clone - germanium, silicon or hybrid - any of which can be built using this PCB. Having 3 germanium transistors, 2 of which are biased by their own leakage makes the classic circuit very susceptible to changes in temperature, i.e. hotter = more gain & noise. Both the silicon and hybrid options offer a sound very close to the original, but with the advantage of improved temperature stability.

As you may know, silicon transistors usually require a negative ground, whereas germanium usually require positive ground, meaning they are incompatible with one another. However, in this case we are using silicon types that use positive ground, meaning there is the option to mix and match transistor types to produce a “hybrid” Zonk*. There are examples of original Zonk Machines from the 60’s that feature a 2n4061 silicon transistor for Q2, but not for Q1 or Q3. I have made my own modifications to the circuit to allow for silicon transistors in these positions, but the changes only relate to biasing, and can be omitted from the build if you want to use the PCB for a classic germanium Zonk. The signal path remains the same as the original.

The Zonk is simple to build in terms of component count, but tricky to perfect. Many variables interact and need to be considered, and so the PCB comes with detailed instructions and knowledge accumulated from hundreds of builds over many years, showing exactly how to select transistors and tune the circuit.

Please note the order is for the PCB and instructions only. The pictures here of populated boards and finished pedals are illustrative only.