This is a 4 transistor audio amplifier circuit. Which is a 4-transistors complementary push-pull amplifier, that shows the basics of audio amplifier design.
Hight Bridge Amplifier using TDA2030
This is high power Mosfet amplifier,300W - 1200watt at load 4-8 ohms , For use in applications such as concert, theater, festivals, most suitable. [...]
This 100W amplifier circuit by transistors, but very well OCL amplifier schematic.Use transistor MJ15003,MJ15004 as main. Power supply +38V 0 -38V 3A. [...]
This is small integrated amplifier at 20W using a TDA2004 or TDA2005 IC,use 12V supply for BCL car audio amps[...]
Good transistor audio amplifier circuit, at 40 watts OCL RMS using 2N3055+MJ2955 is easy to build,and very inexpensive. To use Power Supply +35V -35V 2A.
This is an LM386 audio amplifier that can be used with a small 9 volt Battery Operated,Current use as little as 5 milliamps.And amplification up to 500 mW.