Erica Synths EDU DIY EG Eurorack Module Kit - Manual (Page 10)

power from the square wave LFO. Is this a problem? That very much depends on what
your goals & context are. In this current form, the envelope can only properly function if
two external conditions are met: the circuit triggering it (in our case, the LFO) needs to be
able to provide enough current. And the circuit we’re controlling (in our case, the filter)
needs to draw as little current as possible from our envelope.
Why? Let’s imagine we put a big resistor between our LFO and the envelope. This way,
we are severely limiting the amount of current flowing into our circuit. And that means that
even if we dial our attack and release pots all the way down, charging and discharging
our capacitor will not be instant –
as we’d expect –, but instead would take a while.
On the other side, imagine our filter was also using the envelope to drive an LED. LEDs, if
you don’t know, are basically just diodes that light up when a current flows through them.
Since they’re pretty power-hungry, our filter’s LED would eat up most of the current
coming through the attack pot, preventing our capacitor from ever really being charged
up. And that would severely restrict our envelope’s range. Now granted, this is a worst
case scenario.
Well-designed modules should always have high-current outputs and
low- to no-current inputs . Which, ironically, is a standard our envelope here does not
live up to at all. It eats up our oscillator’s signal, while providing barely anything for the
filter.
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