About the Circuit.

This audio amplifier is of high efficiency as it produces an output power of 18W , and that too with very less components. A shunt feedback configuration is setup here using two transistors, one MOSFET, and also with a few resistors and capacitors for optimum perfo
rmance and noise free operation .Though a small circuit in appearance, the circuit using an 8 ohm speaker can produce 18 watts, or 30 watts for a 4 ohm speaker. As we are using only a few components a well regulated, highly stable power supply is to be used.Thus an improved performance as well as stability is obtained, which is necessary for obtaining a constant output for varying loads and most importantly for reducing the noise. The DC voltage regulator rating should be sufficient enough to produce more than 3 Amps at 40 volts.

Circuit Diagram & Parts List .

18w-mosfet-amp-amp-ckt.JPG

Tips .

  1. The PCB used for a circuit like this should be of high quality.
  2. In order to obtain better performance always select a good preamplifier board with a tone control prior to this amplifier.
  3. If are unable to set up a preamplifier , no need to worry because the main amplifier has enough capacity to stand on its own. Preamplifier is needed only if you notice substantial clipping in the audio output.