Here the schematic diagram of headphone amplifier which built based single MOSFET as the main amplification component. This circuit is quite simple and easy to built with minimum cost.
- The MOSFET type is IRF610.
- The above diagram design is for one channel only, just build the same circuit in one PCB to make it stereo channel.
- All resistor wattage is 0.25W except the resistor around LM317 which is 0.5W
- Connect signal ground to the power supply ground. If there is a hum, try connecting with a resistor parallel with capacitor.
- Use regulated power supply 10-12VDC
The amplifier concept is simple and follows a typical single-ended class A circuit utilizing an active constant current source (CCS) in place of a passive resistor. A CCS doubles the efficiency of the circuit over that where a passive load resistor is used, bringing it to a maximum of 25%.