Every major chip manufacturer (Texas Instruments, Analog Devices, Microchip) publishes "App Notes." These are PDF documents that show you exactly how to use their chips.
focused on audio electronics, including preamps, fuzz pedals, and ring modulators. 106 Easy Electronics Projects : A classic resource from World Radio History containing practical transistor and hobbyist circuits. Make: Electronics : A high-quality educational PDF from Cornell University electronic enthusiast projects and circuits pdf