[sdiy] HELP! How can this possibly work? Buchla Music Easel env generator?

[Dave Leith]

The circuit diagram is on Magnus's site here
http://rubidium.dyndns.org/~magnus/synths/companies/buchla/Buchla_2080_3_200.jpg

The question is about the pulse input <6>. If the puse comes thru
a120K resistor to point <6> then the circuit is supposed to sustain as
long as the pulse is high. Once the pulse goes to 0 volts then the
decay begins.

In the other mode (transient) the pulse goes thru a 390K resistor to
point <6> then the envelope generator is supposed to be in transient
mode where the envelope is triggered and should go thru it's cycle
independent of the pulse going low.

IC4 where the pulse is conditioned appears to be a comparator that has
2 states hi or low. This is the part that is the mystery to me. How
are the two envelope generator states created from this.

Envelope generator operation is also explained here.
(http://rubidium.dyndns.org/~magnus/synths/companies/buchla/PaMtEO_16.gif)

Front panel wiring to the envelope generator is here.
(http://rubidium.dyndns.org/~magnus/synths/companies/buchla/Buchla_2080_13B_200.jpg)

Thanks for any help that can be offered

Dave