Here is a little audio amplifier similar to what you might find in a small transistor radio. The input stage is biased so that the supply voltage is divided equally across the two complimentary output transistors which are slightly biased in conduction by the diodes between the bases.
http://ourworld.compuserve.com/homepages/Bill_Bowden/page8.htm
This is an unusual circuit for an ultra-low distortion power amp. According to my original notes the circuit is dated January 1977 so the circuit is not exactly modern but it is still sufficiently different to be interesting.
http://www.4qdtec.com/pwramp.html
Here is a little audio amplifier similar to what you might find in a small transistor radio.
http://ourworld.compuserve.com/homepages/Bill_Bowden/page8.htm
It uses TDA2030 Common audio power amplifier IC. Only one channel is shown.
http://margo.student.utwente.nl/el/audio/pwramp01.gif
This circuit uses a switched capacitor filter IC from National Semiconductor to filter signals with
http://www.discovercircuits.com/PDF-FILES/3kscfamp.pdf
operates in Class AB mode; the single 470R preset resistor controls the quiescent current flowing through the BD139/140 complimentary output transistors.
http://www.mitedu.freeserve.co.uk/Circuits/Audio/2wamp.html
Hiraga Le Classe A 20W
http://www.tanker.se/lidstrom/hir20a.gif
10 Watts of Single-Stage Single-Ended Class A
http://www.passdiy.com/pdf/zenamp.pdf
The amplifier operates in Class AB mode; the single 470R preset resistor controls the quiescent current flowing through the BD139/140 complimentary output transistors.
http://www.mitedu.freeserve.co.uk/Circuits/Audio/2wamp.html
provides 14 watts of power, but can provide much more simply by increasing the power supply voltage.
http://michaelgellis.tripod.com/audioamp.html