Simple home audio power amplifier circuit schematic

Here is a new audio power amplifier schematic built around TIP darlington pair transistors. You can use this circuit for home audio power amplifiers and car audio amplifiers. The TIP142 and TIP147 darlington pair transistors forms a push pull high power amplifier configuration while the two BC558 PNP transistor provides a mini audio pre amplifier circuit. The audio signal is applied to the pre amp through a capacitor, then it is coupled to the push pull power amp via TIP141 transistor. The values and ratings of different components of power amplifier design are also given in this article. Implementation cost of this mini audio amplifier circuit is too cheap, near $5. The circuit can deliver 150 W RMS to a 8 Ω (150 Watt power amplifier).
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Circuit diagram audio amplifier

Audio amplifier circuit
Click on the circuit for enlarged view 

Components required

  1. Transistors (TIP141; TIP142; TIP147; BC558 x 2)
  2. Resistors 7 watt(0.33Ω x 2)
  3. Resistors 1 watt (3.3kΩ x 2)
  4. Resistors ¼ watt (22kΩ x 2; 220Ω; 1.5kΩ; 33Ω; 27kΩ)
  5. Capacitors 50V (100µF; 10 µF x 2)
  6. Speaker (8Ω, 150Watt)

Working of 150 watt amplifier

  • Our new audio power amplifier project is based on TIP 142 and TIP 147 (complementary darlington pair power transistors which can handle 5 A current and 100V).
  • The two PNP (BC 558) transistors forms a pre amplifier section to the preceding high power push pull amplifier built around TIP141, TIP 142 and TIP 147 darlington pair transistors.
  • We are using 2 PNP transistors to form a preamplifier section, it is nothing but a differential amplifier to improve overall performance of the amplifier. The application of a differential amplifier in the input phase reduces noise.
  • Input signal is applied to the differential amplifier section via 10µF DC decoupling capacitor. Capacitor removes the DC voltage from the input audio signal.
  • 10kΩ potentio meter is used for volume controlling.
  • Feedback voltage is applied through the 22K resistor.
  • A complementary class AB push pull power amplifier stage is built around the TIP darlington pair transistors to drive the 8Ω 150 watt speaker (The circuit can deliver 150 W RMS to a 8 Ω).
  • The diodes (1N4007) biases the complementary pair and guarantee class AB amplifier configuration.
  • Transistor TIP141 drives the push-pull pair (TIP142 & TIP147) and its base is directly connected to the collector of pre amplifier stage.
  • +/-40V, 5A dual power supply is necessary to provide supply for this simplest amplifier circuit. Use 30V-0-30V step down transformer and construct a dual lab power supply for this project.

Pinouts of TIP141, TIP142, TIP147 and BC558

Other popular amplifier circuits

37 thoughts on “Simple home audio power amplifier circuit schematic

  1. The 150W output power of this amplifier is impressive. What are the distortion and other specs of this amplifier? Can the input signal be fed from another preamp? If so, can we do away with the volume pot control? Has anyone used this in a HiFi setup and what are the comments and impressions? Sorry for so many questions. Thank you.

    • Hey Robert,
      You can use preamp with this circuit without the volume pot control. Since we’re using transistors only there’s probability of distortion.

  2. You do not require anything like a 150 watt amplifoer for home use, which needs a 5 ampere power supply that uses up your electricity rather fast as two are needed for stereo. A TEN watt amplifier x 2 for stereo, is more than enough power for home use and at 1.5 amperes is quite cheap to run and costs a lot less time and money to build. Speakers that can handle high powers are expensive, whereas decent 10 watt speakers are relatively cheaper. I have used 10 watts now for many years and when I increase the volume I even get complaints that it is too loud. Most high output amplifier transistors require large heatsinks and take up more room which is another factor worth consideration if space is limited. Always think about the cost and space before embarking on any hi-fi system. HL.

  3. I build this and it sounds good. but when i increasing volume, 33R become very hot and get burned. please help.

    • this circuit power supply is not correct .TIP147 + power supply you will give direct collector otherwise the resistance 33 ohms melt.

  4. I built tis amp works best on low voltages up to 30 beyond which tip 142 gets red hot and short circuited. Any solution. Also it is tip41 or tip141 please clarify.

  5. With some nominal change, the circuit is now working absolutely ok at 45 volt dc. A nice and cheap circuit.recommended to be built by all interested.

  6. In series with 3 diodes, instead of fixed 20 ohm resistor, I used a preset 100 ohm and adjusted it for 50 ma current. Circuit is working ok and as it is.

  7. I like this amp circuit. However I need to run it off of +-51 VDC as that is what the SMPS that I am using puts out for the amplifier. I want to put this in my Fender PD250 PA System. What changes to I need to make to the components to make this work if any. Also when I try to simulate this circuit in Multisim, the wave forms are getting cut off please help.


  8. Very nice knowledge infos.thousand thanks for you all guys.i am beginner audio builder and always wanna build outstanding audio craft most for tiny and simple circuit is.

  9. nice circuit, but can the darlington pair transistors be replaced with a non darlington pair transistor. please reply

  10. Hi,

    Can i use 2 different DC power supplies of +30 and -30 to power the circuit. Is there any issue could occurs if there is some level difference between these two supplies or i am bound to use a centre tapped transformer to power this. thanks

  11. Hi,

    I made this circuit and appply +-30 volts but it does not amplify any bit sound. does it work on these voltage levels? may i use 2 different supplies of +30 and -30 volts? please help me hurry. thanks

  12. Hai sir this circuit is good working in medium volume level but the low volume working is little distortion.sir,what is the problem. I touch the -45 point no distortion.please help me

    • i built the amp and the one channel distorts at low volume
      it sounds like the speaker is blown but its not
      i think i made a mistake somewhere on the circuit board

  13. Can i use 0.33ohm 5watt instead of 0.33ohm 7watt…….. Nice circuit it does work. I have built it before,, this time i cant find 0.33 ohm 7watt…… I need help please

  14. hey this circuit is not correct fault in positive power supply +45 give direct tip 147 darlington if you will give threw via 33 ohms its burn

  15. Hey, i made this circuit and for some reson at over 1/2 of volume the center voltage gets out of balants and with out a light bulb the tip142 shorts out (and simply explods).
    I dont know if this is it but i could finde a 1w 3.3k instead i used a 3.9k at 1w, could this be it?
    Please help me guis. Thanks

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