Yaesu MH-31 Microphone modification.

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Buick Mackane
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Yaesu MH-31 Microphone modification.

Post by Buick Mackane »

This mic is supplied with a few yaesu radios and it uses a dynamic element which is probably fine for a lot of radios but it's a real struggle using it with the yaesu FT-817. You usually end up with the mic gain set high and the mic about an inch from your mouth which doesn't do the audio any favours, The mod involves swapping the dynamic element for an electret element and adding a few capacitors on the tone switch, Pretty simple but very effective mod, I now have the mic gain set at 20 and don't need to shout or eat the mic,

All details of the mod are covered in the link below, I used a 470nf capacitor not the 1uf electrolytic mentioned in the link as the original mod involves having the negative of the electrolytic tied to the electret mics positive rail and i wasn't keen on doing that.

Audio wise the two tone settings (47nf or 470nf) sound much the same according to on air reports, But i find the 470nf setting gives more audio drive.

If you attempt this mod you do so at your own risk although its pretty easy, Don't skip over the part that involves adding two caps to the tone switch, If you leave the switch as standard you'll send 5 volts to the radios audio amp when the switch is in position one, So carry out all steps as described in the link.

https://m0ukd.com/mods/yaesu-mh-31-elec ... ification/
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Re: Yaesu MH-31 Microphone modification.

Post by Tim »

An inch away from your mouth is the correct distance. When setting the gain in the radio menu the peak of your voice should not go past the top end of the ALC guide, if it does then you are over driving the audio output. Always remember that audio is in the ear of whoever is listening to you, not what you think you sound like.
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