Prototype. AR knob spacing as well as feature set may change. In this one prototype you may notice incorrect front panel text.
This is the all-transistor AR envelope from the Buchla 410 Module Cluster.
Modes include switchable Sustain or Transient (one-shot) modes, a X10 switch for very long envelope times (switching between the 1uF timing capacitor and a 10uF). Lamps indicate envelope output level. Not LEDs, so remember that lamps cannot follow the fastest times possible with this device.
Lamp circuitry is not included on this etch but may be assembled on a rectangle of perf board.
The looping/comparator section is from the 212 envelope schematics and is supposed to fire an output pulse when 0.2V is reached. I didn't manage to get this section working but hopefully someone will chime in.
Initiating it would require a dual-section Mode switch, with one side wired to +15V with a diode and a small RC circuit to reduce it to a pulse, to the input.
Ground, +15V, +24V. Small 24V power supplies can be found at surplus stores and at Mouser for not much money.
This is a 100/410 module, which like the black-knobbed early 200 modules, outputs a +15V maximum voltage. The 110 Gates etc. require +15V to sweep their full response range. Using this with later 200 and 200e modules can pose some issues; VCAs will respond strangely. For things such as filter frequency or oscillator frequency, this is not a problem.
It should be possible to mod this circuit to output +10V; see the Modifications section at the end of this post.
Some 200e modules might not output the correct gate signal to fire these circuits. Will have to find out.
The prototype shown was built with 2N3904 and 2N3906 transistors instead of the indicated 2N3565 and 2N4248 and it works just fine.
for a total of
30) 2N3565 and
1) 2R2 1/2W
1) 220uF 50V electrolytic
6) 1uF Tantalum
6) 10uF Tantalum
For both the shown Quad version and for the Hex etch art as well.
CONTINUITY CHECK, PARTS LEGEND:
The 1uF timing capacitor may be brought out to a switch selecting between it and say a 10uF for 10X slower rates.