300W high fidelity power amplifier circuit

The output power of this amplifier circuit is 300W when the load is 8Ω and BTL mono, and 100W 100W when the load is 6Ω and stereo output. The circuit uses the high-power amplifier LM21CL of National Semiconductor. It uses an ordinary TO-3 metal package (the volume is the same as that of a general high-power triode), with a rated output power of 150W, a maximum supply voltage of 80V, and a maximum output current of 10A. The circuit is shown in the figure.