If you are looking for Small PA amplifier circuit using transistors. This may be first choice for you. The output is 100 watts power, very loud and very durable, easy to builds. Is is real?
See STK4231II and build a 2 channel OCL 100W stereo audio amplifier circuit with PCB layout. It's easy, small without adjusting, and cheap.
DC servo amplifier circuit, OCL Output 100w , use mosfet k134+j49 or Mosfet J162 + K1058, Output 112W at Speaker 8 OHM. Power Supply +56V/-56V 4A /Ch. [...]
This 100W amplifier circuit by transistors, but very well OCL amplifier schematic.Use transistor MJ15003,MJ15004 as main. Power supply +38V 0 -38V 3A. [...]