Comment by creer

> The key diagram is the one that shows the signal path [...] Everything else is supporting circuitry.

This is also very misleading in that all this supporting circuitry AND the stuff not even shown, such as wires routing with respect to each other and with respect to the inside or outside of a metal case ALSO contribute. All this stuff contributes to basic functionality ("noise", "hum", etc) and to finer performance (frequency response, dynamic, distortion, crosstalk, etc).

It's easy to confuse the map for the territory, the schematic for the physics of the thing. And common electronics schematics abstract away much that does matter. Engineers and builders with some experience will pay attention to this without bothering to include it in the schematic.

Pay attention when following a magazine article for example: most of the time it will point out the why of several decisions. Why they placed this and that away from each other. Why these wires are routed this way...