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DIY Amplifier not working, speaker makes popping sound, not sure what is wrong?

timjg

Nov 13, 2019
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This is my second attempt at making a DIY amplifier using a LM386 chip. My first attempt it worked but with lots of speaker distortion and then when I put it on a circuit board it did not work at all. I tried again with all new parts, except the speaker. I can hear the music very softly, but it has a loud popping sound that changes speed of interval between popping sound depending on how the volume or gain is set. Ive attached images of the schematic and the "colored version". The speaker is 8 ohm .5watt so I am not sure if the type of speaker is the problem or something else that I am messing up.

Please help, I am motivated to complete this project but these issues have discouraged me.
 

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davenn

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Sep 5, 2009
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I am pretty new and unexperienced with circuitry and datasheets.


Forget the circuit you posted above and just use the circuit on page 11 of the datasheet instead of your one and all will be OK :)
 

Audioguru

Sep 24, 2016
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I think your 9V battery is weak. Try a new one.
EDIT: Of course the amplifier produces distortion if the volume is turned up higher than about 0.4W of output which is about like a cheap clock radio.
 

Bluejets

Oct 5, 2014
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You may also be overdriving the input which will give output distortion.
What are you using as input source?
 

Audioguru

Sep 24, 2016
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You may also be overdriving the input which will give output distortion.
What are you using as input source?
The amplifier has a volume control and a gain control so the input signal level can easily be reduced.
 

timjg

Nov 13, 2019
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I think your 9V battery is weak. Try a new one.
EDIT: Of course the amplifier produces distortion if the volume is turned up higher than about 0.4W of output which is about like a cheap clock radio.
Would getting a higher watt rated speaker allow me to increase volume without distortion?
 

Audioguru

Sep 24, 2016
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The datasheet of the LM386 amplifier IC shows that its output power into an 8 ohm speaker when the power supply is 9V is only 0.4W at low distortion. 0.4W is not loud. Why do you think changing the speaker will increase the output power?

Oh, if the speaker is only 1" in diameter then it produces little squeaks. Then a replacement speaker that is 8" in diameter and in a proper enclosure will be louder.

An LM1875 amplifier IC will produce 4W at low distortion into an 8 ohm speaker when the power supply is 24V and will sound twice as loud as only 0.4W. The LM1875 can produce 33W into 8 ohms at low distortion when the power supply is 60V.
 
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