40W audio amplifier

john April 7, 2010 8 Comments

This is a very excellent 40W power amplifier design using TDA2030 IC and two transistors. The circuit employs only few components and does not require a dual power supply. The input signal is coupled to the non inverting input of TDA2030 through the DC decoupling capacitor C5. The TDA 2030 performs the major part of voltage amplification. As the IC performs amplification, the power supply current to the IC varies according to the input signal. The variations in the positive supply pin are coupled to the base of Q1 and variations in the negative supply pin are coupled to the base of Q2.The major part of current amplification is done by these two complementary transistors.

Circuit Diagram.



  • The circuit must be assembled on good quality PCB.
  • The PCB tracks through which there is high current flow should be made broader.
  • 12V to 40V can be used for powering the circuit. For maximum output, use 40V supply and 4 Ohms speaker.
  • Transistors and IC must be heatsinked.
  • Input and output grounds must be properly decoupled for optimum performance.
  • Manideep
    September 4, 2018

    Can I use it as a Subwoofer Amplifier with low pass filter?

  • ace
    June 24, 2013

    Hi, if i were to want to install a voice chip, where would i have to connect it?

    thank you!

  • B-Jarn
    February 6, 2011

    Im planning to use this amp for a 9 inch 25W sub (no big deal).
    But I just want to know what the minimum current for the power supply, should be? Is 2A enough?

  • ryan
    March 13, 2010

    how about a 40 watt audio amplifier with active controls like volume control, bass control and treble control…

    can you please help find this circuit….

    • Bhanu Prasad Mishra
      February 10, 2013

      I have send u the link go to it & enjoy the ckt … but it is of 30watt cd player ckt..

  • painkiller
    February 1, 2010

    thanks 4 d circit………………………..

  • […] are now in a position to illustrate how a complete tran­sistor amplifier circuit including bias resistors can be formed on a silicon wafer using the masking and photolithographic […]

  • […] 40W audio amplifier | Free Electronics Projects-Electronics … […]

Leave a Reply

Your email address will not be published. Required fields are marked *