Electret Mic without power?

Discussion in 'CB Radio Forum' started by rabbiporkchop, Feb 28, 2017.

  1. rabbiporkchop

    rabbiporkchop Road Train Member

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    I just cracked open my AT-6666 stock mic to cannibalize parts to build a better mic without the acoustic deficiencies of the Anytone mic case, plus having the option of adding a noise cancelling electret in the future,
    and noticed pin 6 with dc voltage is unused. I also noticed no capacitor inside the mic to prevent dc voltage from feeding back into the audio chain. How does this thing work?
    1488299381305.jpg 1488301735659.jpg
     
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  3. CW Spook

    CW Spook Light Load Member

    Looks to me that the schematic is showing a dynamic mic, but that 13 volts is available on the radio connector side for power to an electret if it's equipped with a properly wired cable.
     
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  4. Ridgeline

    Ridgeline Road Train Member

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    I sort of second that, the power is also used for a mic with tone buttons (lack of a better term), the radio is a universal radio, it covers a lot of different markets and could be used in commercial applications.
     
  5. rabbiporkchop

    rabbiporkchop Road Train Member

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    It is an electret soldered to the pcb.
    That's what confused me.
     
  6. CW Spook

    CW Spook Light Load Member

    Well, if that's the case, I don't know for sure either. The wire marked RX on the schematic is actually for the up-down buttons. Maybe in TX it supplies power to the mic element.
     
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  7. rabbiporkchop

    rabbiporkchop Road Train Member

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    Looks like I got a new project.
    If I'm lucky it will sound almost as good as the Heil PR40.
    [​IMG]
    [​IMG]
     
    Last edited: Feb 28, 2017
  8. Ridgeline

    Ridgeline Road Train Member

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    It's not an electret element.
     
  9. rabbiporkchop

    rabbiporkchop Road Train Member

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    What isn't?
     
  10. Ridgeline

    Ridgeline Road Train Member

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    That isn't
     
  11. rabbiporkchop

    rabbiporkchop Road Train Member

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    It sure looks like some sort of transducer. If it isn't an electret then what is it?
     
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