Diodes and resistors are a anti-clipping limiter. They aren't needed. The LED was just a quick and dirty way to counter the inability of the op-amp output to go to the -VE rail. Other methods are also valid.
KenOn Wed, Apr 8, 2015 at 11:35 AM, Sean Ellis tensiontype@... [cgs_synth] <cgs_synth@yahoogroups.com> wrote:
Hi! I'm looking at the schematics for the Cynare and noticed the original version has 2 back to back diodes and 2 resistors in a feedback loop for the envelope scale/invert section. These are missing from the Elby version of the circuit, what do they do to the envelope? I assume they alter the response in some way or are they for limiting the output level?
Same thing with using the LED into the VCA's control pin, does this change the shape of the envelope in any way or is it just to keep parts down? Not sure I've seen that done on other drum circuits before.
Cheers,
Sean
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