Chucko said:Ahh, at last a topic I can contribute to!
Typical guitar amps have a sensitivity on the order of 50 mV for full output. Line level is around 1 V, so you need to provide a voltage gain of roughly 20. For a simple design, try a JFET common-source stage followed by a JFET or MOSFET source-follower as a buffer. You can't get much simpler!