VCA / Envelope

1. A (Attack time)

This slider controls the amount of time which is required for the voltage to reach its maximum level after a key is depressed.

2. D (Decay time)

This slider controls the amount of time required for the voltage to fall to the level set by the SUSTAIN control.

3. S (Sustain level)

This slider determines the level to which the voltage will fall at the end of decay time. Once this level is reached (at the end of decay time) it will be held until the key is released. Note that if the SUSTAIN control is set at maximum, there will be no decay time since the voltage level cannot fall to maximum. With the SUSTAIN control at maximum, then, the DECAY control has no effect.

4. R (Release time)

This slider determines the amount of time required for the voltage to fall to minimum level after the release of the key.

5. Gate selector switch

This switch determines the source which will trigger the envelope generator into action. At GATE + TRIG, the envelope generator will be triggered each time there is a change in pitch. At GATE, the envelope generator will not be re-triggered for changes in pitches which are played legato. In the LFO position, depressing a key will cause the envelope generator to be triggered by the LFO. This is useful for producing rapidly repeating notes such as those sometimes used in mandolin playing. The speed of the repetitions will be determined by the MODULATOR section RATE control

VCA

The VCA is an amplifier whose gain is controlled by a control voltage. In other words, the varying control voltage acts much like a volume control to any sound passing through the VCA. Setting the VCA switch at HOLD will hold the VCA open so that the synthesizer produces sound continuosly. At GATE, the output sound will be turned on and off directly by depressing keys on the keyboard. At ENV, the output sound will be shaped by the envelope generator.

Envelope Generator

Depressing a key on the keyboard triggers the envelope generator into action. The envelope generator generates a control voltage which varies with time according to the control settings. This control voltage is used to control the VCF cutoff frequency point so as to vary the tone color during the production of a note, and/or it is used to control the VCA to give the output sound its loudness contour.