Erica Synths EDU DIY Wavefolder Eurorack Module Kit User Manual
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This means that we have two distinct regions in our graph above: one where the
collector voltage is roughly the inverse of the base voltage – and one where it’s
roughly the same
. So if we send an oscillation into the transistor’s base, every part of the
wave that crosses the 450 mV threshold will be folded over in the output. To make sure
this actually works, let’s set it up on the breadboard.
If you now send a triangle, sine or sawtooth wave into the jack socket connected to the
transistor’s base while monitoring the voltage at the collector with an oscilloscope, you
should see some folding happening.
To make the e
ff
ect easier to understand, I recommend you route the input through a mixer
before sending it into the circuit.
That way, you can play with its volume to see what
this does to the output
. (Spoiler: more volume means more noticeable folding – simply
because a bigger part of the triangle is passing the folding threshold.)
You can try this chapter’s circuit in a simulator. I’ve already set it up for you right here:
you can change all values by double clicking on components.
If you have the mki x es.edu VCF, you can get a sine wave by turning up the resonance all the
way without any input signal.
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