741/Transistor Amplifier
I discovered this circuit on an India blog, which has since vanished. I'm amazed by how good it sounds, especially given the reputation 741s have for being hopeless for audio. It works fine at 12V.
I've tweaked it a bit and designed a PCB, details of which can be found here.
I've tweaked it a bit and designed a PCB, details of which can be found here.