Future Retro 777 Modifications - Manual (Page 4)

There are 3 analog switches that are not used. These are in IC U11, and U14 (part type
4066). These IC’s run between ground and +12v.
Pins for unused switches are:
U11
1) 1 & 2 are input/output, pin 13 is control
2) 10 & 11 are input/output, pin 12 is control
U14
1) 1 & 2 are input/output, pin 13 is control
Infinite sustain for sustained or glided notes
Infinite sustain
As in the original 303, if a long sustain is written for a note’s duration the VCA’s gate
signal will eventually decay until no sound is heard. You can change this so that the gate
signal never decays, and infinite gate times are possible. For this mod, lift the anode end
(side opposite the black band) of diode D20 and run a wire to connect the lifted end of
D20 to the anode of diode D19. You could also use a switch to make the connection of
D20 selectable between its original source and D19.
Turning your VCA’s gate into an ASR type envelope
Variable attack time
You can adjust the time it takes for the gate signal to reach its full potential by increasing
the resistance of resistor R176 (10K). For adjustable attack times, lift one end of R176
and run a wire from the lifted end of R176 to one of the outer terminals of a
potentiometer. Run another wire from the hole which R176 went to, to the other outer
terminal of the potentiometer. Connect the wiper of the potentiometer to one of its outer
terminals so that the resistance of the pot increases as you turn the potentiometer
clockwise. Note that more resistance creates longer attack times, I would recommend
using a 50K or 100K potentiometer for this mod, but feel free to experiment.