This scan is from my old ETI Circuits #2 from the 70’s. It’s about the best op-amp info you are likely to find. With a bit of knowledge, these six circuits are an instant ready-reckoner and allow you to do almost anything!
If you’ve no knowledge, they’re just squiggles on paper. But then so is any language on paper…
If you want to learn then they are ideal to have sat next to a larger circuit to help with the comprehension process. Like your mixer project! BTW, how’s it going with that?
Because of some recent site activity, I’ve checked and realised a picture was missing from a previous post here: https://strangelyperfect.tv/79/headphone-amp-circuit/ so I’ve updated that and added a bit of info from the same mag above. There’s shedloads in it. I can see why I never chucked it out now! I’ve found someone here in Australia with the same disposition as me – check the circuits! Nice and simple, and you’ll get that authentic analogue sound, as well as getting some understanding along the way.
Most of this sort of information I vigorously used and modified (along with other stuff, of course), to make our Crawling Chaos hardware. So it does work! 😀