Today I learned that ditching this stage makes it just a normal octave down, not two octaves! I kept thinking this was just a buffer stage while tinkering. What exactly is this doing? Is there some sort of summing or cancellation that kills all but the second down octave here?
And what happens if there's resistance between pins 6 and 7? Does it mess up the octave, or does it amplify? (Wondering if this is another way to boost the second octave down, but I don't want to cut the trace and experiment without some inkling that it might work.)
I'm very interested in this.