Designed for self-powered 8, 4 & 2 Ohm loudspeakers Bass-boost switch
http://www.redcircuits.com//Page33.htm
A 10-W Design giving subjectively better results than class B transistor amplifiers
http://sound.westhost.com/jll_hood.htm
A simple design that uses the NTE 1606 Power Amplifier chip.
http://www.ee.washington.edu/conselec/Sp96/projects/rphou/final/index.htm
about 660-mW output can be gotten with the 16-ohm speaker.
http://www.hobby-elec.org/e_ckt3.htm