Erica Synths EDU DIY Mixer Eurorack Module Kit User Manual
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Because that operation stays the same regardless of what the exact input voltages are,
the output will always be the mid point between them.
That’s why the setup above
works as a mixer: it simply puts out the average of our input signals
. To try this in
practice, let’s set it up on the breadboard.
For your two inputs, you can use any regular audio signal –
coming from an oscillator,
your phone, or a drum machine, for example. You should then be able to hear both
signals in the circuit’s output. That is, if you connect it to anything with a built-in amplifier.
If you use headphones directly, you’ll barely be able to hear the mixed output
. This is
because this mixer is passive – meaning that it does not amplify the mixed signal.
Why is this a problem? Because the two resistors strongly limit the amount of current
that’ll reach and drive your headphones.
In electronics jargon, we’d say that this
circuit has a really high output impedance
.
You can try this chapter’s circuits in a circuit simulator. I’ve already set them up for you right
here: –
you can change all values by double clicking on
components.
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