Double-negative mixer – Erica Synths EDU DIY Mixer Eurorack Module Kit User Manual
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DOUBLE-NEGATIVE MIXER
So how do we get rid of the inversion? Easy – by inverting the inverted signal again. For
that, we’ll simply set up another inverting bu
ff
er with just a single input and place it
between the previous one and the output socket.
Since an inverted signal can be useful in certain situations though, it makes sense to keep
it connected to a dedicated output socket where we can pick it up when needed.
First o
ff
, verify that you still get an audio mix at the new non-inverted output. If that works
fine, test it with CV coming from an envelope or an LFO. For that, connect it to the mixer’s
input, while sending the non-inverted output to a filter’s CV input. Close the filter
completely. You should hear the filter open up in sync with the envelope’s status LED.
Next, use the inverted output instead while turning the filter’s cuto
ff
knob all the way to
the right. The filter should now close down as the envelope’s status LED gets brighter. So
the mixer is indeed inverting the envelope’s CV signal.
You can try this chapter’s circuit in a circuit simulator. I’ve already set it up for you right here:
–
you can change all values by double clicking on components.
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