As its name implies, the General Envelope Generator is a "general-purpose" Delay-Attack-Release envelope (or DAR, like the badass 70s stuntman, Dar Robinson). Unlike the Voice Panel Envelope Mod envelope generators, it's not hard wired to anything, so it's necessary to patch cables to gate or trigger it and route its output to appropriate CV inputs.
It's important to understand that the General Envelope Generator is monophonic. Unlike the Voice Panel envelopes, which are independent for each note played, the General Envelope Generator affects all mod destinations equally, at the same time (this is what the kids what the kids usually refer to as "paraphonic").
How a DAR Envelope Generator works:
When the envelope is triggered, the Delay knob setting defines how long the envelope "waits" at 0 volts before the attack stage begins, then the attack stage defines how long it takes for the output voltage to rise from 0 to 5 volts. Once the attack stage reaches 5V, it remains there until the key is released (unless Auto mode is engaged, we'll explain below). The release control defines the length of time it takes for the voltage to fall back to 0V when the gate input voltage is removed, i.e. when the key is released.
General Envelope Generator Controls
Out 1/2/3 jacks- These are the General Envelope Generator signal output jacks; each of these outputs a slightly different version of the envelope with respect to polarity as follows:
Out 1- +5V at rest. Attack/release stages move from +5V to 0V and return to +5V upon release.
Out 2- -5V at rest. Attack/release stages move from -5V to 0V and return to -5V upon release.
Out 3- 0V at rest. Attack/release stages move from 0V to +5V and return to -0V upon release (start with this one if you're not 100% sure how this stuff works).
Delay- Defines the length of time before the attack phase begins.
Attack- Defines the length of time for voltage to rise from 0V to 5V when the gate voltage is applied.
Release- Defines the length of time for voltage to fall to 0V when a key is released.
Signal Out LED- Lights up when any of the General Envelope Generator's stages are currently active.
Auto- This is Korg's terminology for what's commonly known as "one-shot mode." It can be used with any of the keyboard gate/trigger out jacks at the bottom of the Master Panel, but it's especially useful when using the Trig Out Multi jack (because a trigger signal is a very short blip of voltage).