Chop wood, carry water. Using cookbook circuits is kind of like that zen story. You come full circle. There's little enough honestly new in electronics that

Chop wood, carry water. Using cookbook circuits is kind of like that zen story. You come full circle. There's little enough honestly new in electronics that almost anything you do will look cookbook to an outsider. Designing actual products is exacting and deep, though. An example to look at is the writeup nwavguy did on his O2 headphone amp. He makes it look easy. The core amp is not an app note design or reference design but if he'd chosen the equivalent parts from TI it just about could have been. It's very straightforward. There is nothing exotic in it. The parts are cheap. The layout is even pretty mundane for high end audio. And yet it measures to be just about flawless, it has a nice no-pop turn-on circuit, etc. and there are plenty of headphone amps you can buy that do not. Without specific experience and expertise in audio design most fully qualified EEs would pathetically struggle to make something that nice. It's one of the best electronic designs for hobbyists I've ever seen. All of you should build one if you think you might want something like that. The only flaw I've found in mine is that the hysteresis on the low battery cutoff is not sufficient for some batteries (as they age and the internal resistance goes up) and it can "motorboat" before the battery cuts out. A really good low battery cutoff circuit is also surprisingly challenging. “The novice says to the master, ‘What does one do before enlightenment?’ ‘Chop wood. Carry water,’ replies the master. The novice asks, ‘What, then, does one do after enlightenment?’ ‘Chop wood. Carry water.'”