Thursday, March 28, 2019

LM386 amplifier circuit schematic diagram complete 99.9% noise removal from ground loop

For those who are new to the LM386 IC may stumbled to a point facing all sort of noise related problem when using it to make an amplifier circuit just like me. It can be very challenging to avoid the sensitive noise and in fact the ground signal from our body contact also can cause significant distortion to the sound output of the circuit. You can try this just by putting your hand or touching one of the circuit component that is not grounded - the distortion noise is very obvious.

There are many videos on YouTube from some experience and experts showing how to avoid the ground loop noise from the Lm386 circuit by correctly connecting all the ground connection. Indeed this has very significant improvement that we should take note how to connect the ground to avoid noise.

However this solution is not enough to completely remove the ground noise - and when you put your ears close to the speaker you can still significant listen to the screeching / crackling noise in the output even if there is no sound to amplify. Indeed it is very annoying and frustrating for some at least to me. Especially earphone / headphone the noise is very obvious since it is placed right on the ears - the noise is not very pleasant to hear.

So after making some research i discovered the perfect solution to avoid the ground noise. And two of this component place at the input and the output would ultimately remove the noise. When there is no sound to amplify there is 100% clean no noise at all completely quiet. The two component are a mini transformer place at the input (step down mode) and a coupled inductor place at the output.

The circuit schematic is look like this. Now for the first time you can use the LM386 circuit to make a mini earphone / headphone amplifier without worrying about the distorted crackling and screeching noise. This is for real 100% working circuit as per prototype shown in the video!





Real physical schematic diagram LM386 noise cancel (remover)

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13 comments:

  1. UnknownMay 9, 2017 at 11:59 AM

    Thanks Again👌. My final question ➡ One of the side of Mini Transformes have 4 PIN & Other side have 2 PIN. So let me finish my Amp🔈🔉🔊

    ReplyDelete
    Replies
    1. NeoDIY.comMay 9, 2017 at 7:41 PM

      I am not quite understand your question...actually both transformer have 4 pins -- 2 pin on each side.

      The input transformer = 4 pins
      The output coupled inductor = 4 pins

      The only different between the two is the input transformer have high voltage - connected to the audio and the low voltage side connect to potentiometer and ground

      The coupled inductor is same ratio winding meaning the voltage on both side is the same.

      Delete
    2. NeoDIY.comMay 9, 2017 at 7:43 PM

      By the way my apology there is a mistake in the capacitor polarity on pin 1 and pin 8....it should be the other way around. Negative to facing pin 8 and positive pin 1

      Delete
  2. UnknownJune 22, 2018 at 7:13 AM

    Where can you buy these components? Mini transformer and coupled inductor thanks

    ReplyDelete
  3. NeoDIY.comJune 23, 2018 at 9:13 AM

    Sorry to say i don't know really know who sell them because the mini transformer and coupled inductor was salvaged components from printers power supply and PC power supply

    ReplyDelete
  4. UnknownOctober 8, 2018 at 4:49 AM

    hi...I truly appreciate your work for noise removal. Can you give detail specification of the input transformer and the output coupled inductor ?

    ReplyDelete
    Replies
    1. NeoDIY.comOctober 8, 2018 at 7:05 AM

      Primary with center tap...mini transformer you could harvest from power supply like printer or pc...and the coupled inductor also from power supply

      Delete
  5. RonakMarch 14, 2019 at 4:29 AM

    please send me details about Transformer and inductor?

    ReplyDelete
  6. RonakApril 5, 2019 at 9:57 PM

    Please which type of transformer use in this circuit and if remove noise using transformer so, can we remove noise using grounding ?

    ReplyDelete
  7. NeoDIY.comApril 6, 2019 at 8:28 AM

    Mini transformer step down would significantly reduce the noise and with the help of coupled inductors at the out put as shown in the circuit. There is also 1k resistors to join the output with the negative which also help it in the process of noise reduction to the LM386 amplifier.

    One more thing make sure you build a circuit with electronic components like capacitors, resistors, as close as possible to the LM386 circuit as it helps to reduce the distance travel of electric current and it help to reduce the noise to capture unwanted signal from surrounding environment.

    I hope this comment tutorial help in your Lm386 audio amplifier project. cheers..!!

    ReplyDelete
  8. Balqis BudimanJuly 22, 2019 at 7:24 PM

    Trasnformer is used for AC right ? How does it function in this DC circuit ?

    ReplyDelete
    Replies
    1. NeoDIY.comJuly 23, 2019 at 5:42 AM

      Transistor is the key...the transistor will generate repetitive current just like AC and will power up the transformer

      Delete
  9. NeoDIY.comAugust 6, 2019 at 8:38 AM

    Hi Youtuber,

    I recently came across your video in YouTube,

    how to reduce amplifier noise



    I have a similar problem and I would like to have your help.

    I am using a 4440 dual IC amplifier, with transformer, there are 2 potentiometers for bass and treble. The amplifier comes in a steel box, when the potentiometers are mounted in the steel box, there is no noise,

    During my DIY project, I extended the bass treble wires to mount it in a wooden cabinet, when I do that , I hear heavy noise.



    I observed that when the wire of the potentiometers (bass and treble) are kept near the transformer , the noise reduces. When I tried to move the wires, when I bring my hand near the wires , then the noise starts coming.

    I think you demonstrated a similar problem.

    Can you please guide me how to use a coupled inductor, in my circuit.

    varundevan@gmail.com

    01:31 (22 hours ago)

    to me

    Hi Youtuber,

    I recently came across your video in YouTube,

    https://www.youtube.com/watch?v=u9_fOnYrYQw&list=PLpVytzOrHwZ1U9OtwgD2-HHZFuKf6gEzB



    I have a similar problem and I would like to have your help.

    I am using a 4440 dual IC amplifier, with transformer, there are 2 potentiometers for bass and treble. The amplifier comes in a steel box, when the potentiometers are mounted in the steel box, there is no noise,

    During my DIY project, I extended the bass treble wires to mount it in a wooden cabinet, when I do that , I hear heavy noise.



    I observed that when the wire of the potentiometers (bass and treble) are kept near the transformer , the noise reduces. When I tried to move the wires, when I bring my hand near the wires , then the noise starts coming.

    I think you demonstrated a similar problem.

    Can you please guide me how to use a coupled inductor, in my circuit.



    My amplified circuit is like this

    Image result for 4440 ic



    I request to help me with this problem.



    Thanks in advance



    Regards,

    Fellow electronic DIY Guy.

    My amplified circuit is like this

    ReplyDelete

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