ADM Console 780 Module - Q About Mic/Line Pre Section

Referring to the attached schematic, the second stage uses an LF356 opamp with a simple buffer. The gain switch on another page shorts out R34 for all but the highest gains so A3 usually runs at unity gain.
My question: what is the purpose of C8 from the LF356 output pin to ground? Intuitively I would think increasing the capacitance on the chip's output would not be a good thing, but I guess I'm missing something. Your thoughts?
Thanks.

I presume that tiny cap was added for stability reasons at very high frequencies.

Bri

Good question. I don't have a clue. There is a lot of circuitry between the output and the inverted input. But if they were worried about it oscillating at high frequencies, they could have just put a cap directly between the output and inverting input. Totally unclear why they would want to selectively switch it in your shunt to ground. Makes no sense. I must be missing something too.

squarewave said:

Good question. I don't have a clue. There is a lot of circuitry between the output and the inverted input. But if they were worried about it oscillating at high frequencies, they could have just put a cap directly between the output and inverting input. Totally unclear why they would want to selectively switch it in your shunt to ground. Makes no sense. I must be missing something too.

Click to expand...

Perhaps it is local compensation has to do with the input capacitance of the following BJTs. Perhaps abbey can shed some light into this.