ZONK II SI 2026 v1 78386c517fb5

JOHN HORNSBY SKEWES: Silicon Zonk II

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I thought a post was required for the silicon Zonk II, as looking at some schematics online, some appeared to be a little different.  Being a pedal from the sixties, variations and tweaks were not uncommon. 

At the moment, this is probably best known as being the inspiration for the Reeves Zo.

This is fun to play with on the breadboard, and it’s actually a really good sounding fuzz.  

JHS ZONK II – SILICON

I know the mounting point in the centre is a little odd, but this is how the orginal is mounted, and the one I’m amking will be mounted the same way.
JHS ZONK II SILICON FUZZ - VERO LAYOUT

SILICON JHS ZONK II SCHEMATIC

SILICON JHS ZONK II SCHEMATIC

Image from the D*A*M forum datadump – a gold mine for digging through vintage effects.  Photo credits to Graham, who perhaps has the most impressive collection of vintage English effects ever assembled. 

Here’s a better shot of the 4k7 resistor across the 5k fuzz pot

In the shot below, the resistor across the 5k fuzz pot is 3k9 AND there is no pulldown resistor on the input.  Image from Freestompboxes, photo credit to beedotman, who has done an awesome number of layouts for a lot of interesting and/or old circuits.

Essentially though, a 3k9 across a 5k pot compared to a 4k7 is only a matter of a few hundred ohms difference.  You could probably hear it, but it’s unlikely to make a big difference?  

I would not recommend a 10uf input cap without a pulldown resistor or being grounded when the pedal is bypassed – unless you like some switch pop.  Sometimes, not all things old-school are good ideas.

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