Description.

The circuit diagram shown here is of a 2 x 60 Watt stereo amplifier based on the LM4780 from National Semiconductors. LM4780 is a superb audio amplifier IC capable of delivering 60W Rms power output / channel into 8 ohm speakers. The LM4780 has very low total harmonic distortion (less than 0.5% at full output) and has a power supply rejection ration (PSRR) of 85 dB. The IC requires very few external components and has a built in mute facility. The LM4780 is completely protected using their trademark SPiKe technology and has a signal to noise ratio greater than 97dB. The circuit given here is well suitable for applications like components stereos, self powered speakers, home theatre systems, compact stereos etc.

Circuit diagram.

2X60 watt amplifier using LM4780

LM4780 pin configuration

LM4780 pin configuration

Notes.

  • The circuit must be assembled on a good quality PCB.
  • The amplifier can be powered using a 35V DC dual supply.
  • K1 and K2 must be 8 ohm, 60W speakers.
  • An adequately sized heat sink must be fitted to the IC.

Author

49 Comments

  1. Noninverting inputs are not polarized. The bottom amplifier has inverted inputs. The schema is not working.

  2. Can you make full instructions and send to me i’m confused on the pins for the lm4780, switch with the 10 ohm resistor and the inputs A and B. How could i use a pententiometer to make a volume switch and could i use an audio jack female for the inputs?
    Thanks

  3. Vivek verma

    Sir,i’hv just made the circuit but sound is not clear and IC become very hot when it is in use. Can you help me,where i’m wrong

  4. Vivek verma

    Sir i’hv just made the circuit but sound is not clear and IC become very hot when it is in use. Can you help me,where i’m wrong

  5. Vivek verma

    Sir, can we use laptop stereo output for this amplifier circuit with out using preamplifier circuit…?

  6. i like to assemble this 60 watts IC audio amplifier. will you please send me the schematic and block diagram. i appreciate so much if you can. thank you.

  7. will you please post the ckt diagram with the IC leg numbers.
    reg:)

  8. i have a doubt that t/f 0v should connect to the ground of amplifier circuit or no connection?im using 24-0-24 2amp t/f.i want to know the heat sink size of LM3886.
    thanking sir.

    • seetharaman

      Hi Prakash connect 0 of trafo to common (shown as ground)of the amplifier. The heat sink should be a minimum 2mm thick 20cms by 10cms aluminum. for this size if you use an extruded alloy heat sink with fins will be the best.

  9. hi, I have a SONODYNE MODEL NO SC-3070 amplifier.but have not speaker.please send it to me how many watt @ohms speaker.

  10. Is the output of this amplifier full range? also would it be possible to separate the output into a Low/Mid and High?
    Kind Regards

  11. THIS CIRCUIT IS SO CHEEEEEP!!!!!!!!!! I CANNOT WASTE MY MONEY TO MAKE THIS LM4780 AMPLIFIER

  12. seetharaman

    Hi Devendra try TDA2050 will give you 50watts power with very low distortion. you can use two as push pull amplifier similar to TDA2030 but with lesser distortion figures.

  13. Devendra

    Sir, lm4780 op-amp is not available in allahabad. Can you tell me some simmilar i.c.s for stereo amplifier.
    Thanks

  14. seetharaman

    Hi Shubham our passive tone control unit has got all required controls for a stereo system (one for each channel that is two of each controls). kindly go through the article.

  15. Sir, as you said to place volume and tone controle before inputs a & b using preamplifier,but as this is stereo amplifier hence two preamplifiers must be used and this will cause pair of volume and tones control 1 for each channel. Which is not practical. Tell me sir what to do.
    Probabily i didn’t understand what u said in previous post.

  16. seetharaman

    Hi Shubham LM4780 is a dual channel high power operational amplifier (with inverting and non inverting inputs similar to an operational amplifier). Input A & B should be connected through volume control. A pre-amplifier has to be used before this mail amplifier. Use the passive tone control appeared earlier which has got volume, bass treble controls.
    https://www.circuitstoday.com/passive-tone-control-circuit

  17. What is name of operational amplifier used, and what is lm4780. Please explain i am confused.
    Thank u

  18. I want to know that where i can place volume controle for speaker?
    Thanks

  19. seetharaman

    Hi Rohit This willbe suited for simple stereo system with only two front full range speakers of 60 watts capacity. for side and rear speakers you require amplifiers around 10watts capacity each.

  20. Rohit Kumar

    Hello Seetharaman,

    Can we add more speakers such as front (left & right) rear (left and right) speakers to this circuit.

    thanks

  21. Pls guy i’m new is this circiut tested and confirmed pls i need reply

  22. Seetharaman

    Hi Pattrick you can use 10K potentiometer as volume conrol just before the input to IC pin no 16 and 21 of the IC input A & B.
    you can also refer to National semiconductor application data.

  23. patrick vaz

    Hi Seetharaman,
    Can you introduce a potentiometer as volume control for the above circuit.

  24. patrick vaz

    Hi Seetharaman,
    what is the budgetary cost of this project, excluding the power supply.

  25. patrick vaz

    Hi seetharaman,
    Any PCb schematics available for this wonderful circuit,
    thanks

  26. you suggest me 27 – 0 – 27 transformer @ 2.25Amps for 2 x 60watts but will it required more current on bridged configuration or the transformer ratings will remain same?

  27. seetharaman

    Hi David I am yet to try, ordered and waitng for the chip at chennai. I love STK465 that is discontinued but a great chip by sanyo, kicking for the last 17years at home.

  28. Hi seetharaman

    Did you try this amplifier

    it is working or not ?

  29. IC pin configuration Name and Diagram Pin Name r No match?
    plz Chk VoA or VoB is Speaker out and Hi Name Is not for IC?

  30. Hi, when u try this diagram?
    its really working Amplifier?

  31. seetharaman

    Hi Adnan I have o get the IC and ICL7107 0-200mV panel meter. give me few days time

  32. when you try this then tell me then i will try too

  33. oriola taiwo afeez

    please i need an isolator that can work for an uninterrupted changeover switch

  34. seetharaman

    Hi Adnan I am yet to try.
    You require a 27 – 0 – 27 transformer @ 2.25Amps rating for stereo amp.

  35. is the 32-0-32 volts 4 amp transformer is suitable for this??????
    if not then suggest the power supply???