http://www.ee.washington.edu/circuit_archive/circuits/Micro.GIF
A power MOSFET is biased using a pot (needed to correct for different device characteristics) so that the voltage at the drain is about 1/2 the supply voltage.
http://sound.westhost.com/project36.htm
The purpose of this site is to share a pulse-width modulating Class D audio power amplifier design with the world, in order to involve people that have an interest in this kind of technology.
http://listen.to/audioexperiment
Based on LM383
http://www.aaroncake.net/circuits/amp.htm
A Really Simple Power Amplifier.
http://sound.westhost.com/project12.htm
Latest update of the Low Tim Amplifier, claimed to be a very good sounding design.
http://users.ece.gatech.edu/~mleach/lowtim/
The output power is 360 Wrms under 8 ohms or 550 Wrms under 4 ohms. Distortion is lower than 0.02 percent.
http://users.swing.be/edwinpaij/ampli_mosfet_360_w.htm
Vacuum Tube Audio with many amplifier circuits.
http://www.geocities.com/TimesSquare/1965/music_etc.html