Found an article that talks about the linearizing diodes in the LM13700 (towards the bottom). When connected to a small current, they allow a higher level of input without distortion. https://northcoastsynthesis.com/news/design-mistakes-in-synth-schematics/
2020-09-02 11:16:24 +0000 UTC
Re: the compensation capacitors in the feedback loop of the op-amp, I think those are mostly used when the op-amp is buffering an external connection. I can’t remember the specifics, but it prevents the op-amp from oscillating/ringing, which is more of an issue on external connections because the jumper cables have capacitance.
