Mods to Craig Anderton's First Balanced "Ring" Modulator

JC Maillet (c) 2006

I like this circuit very much - it appeared in the first-edition of Craig's great DIY effects book ... compared to wide-range linear multiplier Ring-Mods this circuit sounds somewhat more erratic - this is because the effect comes from the phase-detector part of a Phase-Locked Loop ... since the frequency based Loop is performing a tracking function on the guitar signal the output transients and decay are largely controlled by secondary loop-locking manifestations - so this can be seen as a two-in-one kind of effect ...

we can take advantage of these manifestations and modify them for even more unpredictable and semi-autonomous behavior ... with the nulling set way off and external VCO control the circuit can be used as a crazy VCO synth - ideal for onstage UFO landings ...

Notes: the series resistor on the VCO frequency-select pot shouldn't be set to lower than around 1k2 or else the 565 can blow ... hard strummed guitar straight into the input is ok but be careful with Fuzz and Preamp levels feeding this un-buffered version of Craig's circuit - I now keep chips for spare for when it does blow ... the 25k null pot can be wired in series with a 500-ohm pot for easy fine-tuning ... one more thing, the cap at the top of the schematic can be switched to a lower value to give the VCO a hi/lo range ... enjoy !!

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