LM386 Amplifier either generating frequencies or noise

Thread Starter

John Cena_1509536050

Joined Nov 1, 2017
5
Hello fellow forum users. I built a LM386 amplifier based on a MP3 amplifier kits instructions for use in a small stereo system consisting of dead reused CD drives. ass the thread title says my amp does not do what its supposed to do. one of my suspects is the L7805 voltage regulator circuitry i put on the same board as to save space inside the CD drive. the values of the capacitors are as follows:
C1: 10V 3300uF
C2: 16V 6800uF
C3: 400nF
 

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AlbertHall

Joined Jun 4, 2014
10,417
Where does the LM386 get its power from?
If it is from the 12V, where does the 12V come from?
What components do you have connected to the LM386?
Do you have the zobel network connected across the speaker?
This is the example circuit from the LM386 datasheet:
upload_2017-11-1_13-37-12.png
 

MrChips

Joined Oct 2, 2009
21,893
You need to describe the noise you are hearing.
Audio amplifiers will emit mains hum if powered from an AC mains power supply. You need to filter the power supply heavily to remove AC ripple.
 

Thread Starter

John Cena_1509536050

Joined Nov 1, 2017
5
Where does the LM386 get its power from?
If it is from the 12V, where does the 12V come from?
What components do you have connected to the LM386?
Do you have the zobel network connected across the speaker?
This is the example circuit from the LM386 datasheet:
View attachment 138466
The LM386 gets its power from a 12V SeaSonic Power supply thats decently filtered.
Also, it seems i left out the zobel network.

You need to describe the noise you are hearing.
Audio amplifiers will emit mains hum if powered from an AC mains power supply. You need to filter the power supply heavily to remove AC ripple.
the noise is less like mains frequency and more like a strong loud hum that disappears when the switch terminals of the potentiometers are touched.
 
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