Personal Voice Amplifier Background Hum Trouble

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A user is experiencing a loud buzz in their personal voice amplifier circuit, which includes a dynamic mic, a 3v class A preamp, and a 6v LM386 amp. The buzz disappears when they touch the potentiometer, suggesting a grounding or shielding issue. The user has replaced ceramic capacitors with polyester ones, which may be affecting performance. Suggestions include checking for proper grounding, ensuring good shielding, and using coaxial cables for audio leads. An oscilloscope is recommended to analyze the frequency of the noise to determine if it aligns with mains frequency.
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Long-time lurker, first post, here goes.

So I'm working on a personal voice amplifier for a face mask. I have the dynamic mic element ("www.accusonicproducts.com/pdf/G01A009-PFK.pdf2FVVVHLD_Q" ), which feeds into a 3v class A preamp, through a 100k audio taper pot, to a 6v lm386 amp with the gain set for 200.

The problem is that there is a very loud buzz present while using the preamp, which is not present while using on the lm386 amp. However, if I put my finger across the pins for the potentiometer the sound clears and be comes noticeably louder and operates correctly.

The only difference between my circuit and the one schematic I linked to is that I substituted polyester caps in place of the ceramic, I didn't think it would make much difference, but I could be wrong.

Schematics available on demand.

I'm at my wits end, any help would be appreciated!
 
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You need to post the schematic and preferably a picture of your circuit. It is hard get what you circuit is by reading.
 
riley_cultist said:
Long-time lurker, first post, here goes.

So I'm working on a personal voice amplifier for a face mask. I have the dynamic mic element ("www.accusonicproducts.com/pdf/G01A009-PFK.pdf2FVVVHLD_Q" ), which feeds into a 3v class A preamp, through a 100k audio taper pot, to a 6v lm386 amp with the gain set for 200.

The problem is that there is a very loud buzz present while using the preamp, which is not present while using on the lm386 amp. However, if I put my finger across the pins for the potentiometer the sound clears and be comes noticeably louder and operates correctly.
Could well be mains hum. You might not have good shielding, or the Earth braid might not be connected properly, or might be earthed in the wrong place. You are using coax for all audio leads?

Examine the audio on an oscilloscope and determine its frequency, is it identical with your mains frequency? Then probably your finger is performing the earthing function.
 
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