Mosfet power amplifier schematics

This simple mosfet power audio amplifier circuit, with TL071C and 2 mosfet power amplifiers can deliver up to 45W on 8 ohm. This schematic is based on Siliconix application and is based on variations of voltage on the 2 resistors serial inserted on the voltage supplier of the operational amplifier driver.
The MosFet transistor must be mounted on a heatsink at least 1K/W.

Amplifier efficiency is 70%, distortions at cut frequency were at most 0.2% at 20Hz on 8ohm and 10W. With a power supply of +- 30V the mosfet audio amplifier can deliver 45W on 8 ohm and 70w on 4 ohm. Remember that this audio amplifier is not protected on shortcircuits so everytime you switch on check to see if the speaker is connected.

source [link]