The following is a circuit of a power amplifier 140W. This Circuit using 741 IC-based circuit opAmp as strengthening early before the final strengthening by four transistors thereafter. Make sure you use a heatsink on the transistors to reduce excess heat in the transistors.
Power supply used is the type of dual polarity power supply with (+), (-) and (0). For maximum performance, use a stabilized power supply with 40V output voltage and output current of 5A. Do not forget to use the good speakers to get good audio output as well .. 
Good luck …
No. 1 — May 18th, 2011 at 7:42 am
140 watts amp diagram layout
No. 2 — December 15th, 2011 at 7:55 am
this is good circuit diagram but something wrong look this NPN , PNP the No. of 2n3055 & mj2955 and the all. transistor.
Thank you
No. 3 — April 25th, 2012 at 12:17 am
wrong emitter collector tap in the output pnp transistor..the emitter should be tap in the resistor .47 going to vcc section