Zeugma (Zonk Machine MKI)

[andy-h-h]

There is a LOT of info about this circuit condensed here, https://vero-p2p.blogspot.com/2022/12/zonk-machine-component-values-table.html

And this is a rare case of a pedal which isn’t really “paint by numbers”. I tried to make one using different brand transistors with the same hFE/leakage for each transistor and the second one sounded nothing like the first, on a side by side test. This and the MKI are, IMHO, the hardest pedals to make with the right tone; sustain and noise ratio, you need to have a good stash of transistors, lots of patience and be prepared to deal with really esoteric nonsense, some units will have a lot of noise and fizzy decay, which you can almost always solve with a 1-10nf cap from the input to ground.

Ha - it’s funny when researching something and I end up back at my own blog.

Glad someone else found it useful.

 

[Guilherme Collateral]

Your blog Is a really awesome resource! One thing that is cool to add (and is really important on how the Zonk will be voiced) is the internal capacitando of the transistors used. After more than 30 Zonk Builds I have concluded that, specially for q1, the selection isn’t really paint by numbers, the best option is to try a bunch of different transistors and use what sounds best.
Congrats and keep the incredible work at your blog!

(I just read my original post and I said the same thing twice )

Ha - it’s funny when researching something and I end up back at my own blog.

Glad someone else found it useful.

 

[andy-h-h]

Thank you. True - some are definitely brighter than others. There's a bit going on with impedances and inconsistent transistors. Just need a mountain of transistors, a breadboard and a bit of time on your hands Measuring to sort them to some extent does help, but it only takes you so far.