Personal Voice Amplifier Background Hum Trouble

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In summary, the speaker is working on a personal voice amplifier for a face mask. The problem is that there is a loud buzz present while using the preamp, but not when using the amp. Putting a finger across the potentiometer pins resolves the issue. The only difference between the circuit and a linked schematic is the use of polyester caps instead of ceramic. The poster is seeking help and suggests providing schematics and pictures for better understanding. The issue could be caused by mains hum and potential issues with shielding and earthing. The suggestion is to examine the audio on an oscilloscope to determine the frequency and potentially use coax for audio leads.
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riley_cultist
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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.
 
  • #3
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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Related to Personal Voice Amplifier Background Hum Trouble

1. What is a personal voice amplifier and how does it work?

A personal voice amplifier is a portable device that is designed to amplify and enhance the volume of a person's voice. It typically consists of a microphone, amplifier, and a small speaker. The microphone picks up the user's voice, which is then amplified by the amplifier before being projected out of the speaker. This allows the user to be heard more clearly and at a greater distance.

2. Why is there background hum when using a personal voice amplifier?

The background hum in a personal voice amplifier can be caused by a few different factors. One common cause is electromagnetic interference from nearby electronic devices. This interference can create a low-frequency hum in the amplifier's output. Another cause could be a faulty or damaged amplifier or microphone, which can create an unwanted noise in the signal. Additionally, using a low-quality battery or having a weak signal can also contribute to background hum.

3. How can I troubleshoot and fix background hum in my personal voice amplifier?

To troubleshoot and fix background hum in a personal voice amplifier, there are a few steps you can take. First, try moving away from any electronic devices that may be causing interference. You can also try replacing the battery or using a higher-quality battery. If the issue persists, check for any damage or wear on the amplifier or microphone and consider replacing them. If the problem still persists, it may be necessary to consult a professional for repair or replacement.

4. Can background hum be prevented in a personal voice amplifier?

While it may not be possible to completely prevent background hum in a personal voice amplifier, there are some steps you can take to reduce it. Using high-quality equipment, such as a good microphone and amplifier, can help minimize background noise. Additionally, avoiding close proximity to other electronic devices and keeping a strong and steady signal can also help reduce background hum.

5. Are there any alternatives to using a personal voice amplifier to reduce background hum?

Yes, there are alternative options to using a personal voice amplifier to reduce background hum. For example, using a headset microphone can eliminate the need for an amplifier and reduce the chances of background hum. Additionally, using a noise-cancelling microphone or a directional microphone can also help reduce background noise and improve the clarity of your voice.

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