My question is about designing a microphone pre-amplifier that uses an electret microphone. I saw a video of Doug Ford on the EEVBlog, in which he shows some pre-amplifiers for microphones.

My question is: does it make sense build a FET pre-amp for for an electret microphone, considering that a FET it's already inside the microphone package?

Eventually, the microphone noise is produced from the FET inside the microphone, so is it pointless to connect a FET pre-amp outside the microphone?


1 Answer 1


You might choose to use a JFET front end for a guitar amplifier in order to preserve the higher frequency artefacts from significant attenuation when running into an amplifier with impedance somewhat less than 1 Mohm but, for an electret microphone I see no point (given that it might be powered by a 1 kohm to 10 kohm resistor).

so it's pointless connect a FET preamp out of the microphone package ?

I believe that to be a general truth but, I'm hesitant to be definite without a schematic.

  • \$\begingroup\$ Thank you, I dont have a schematic yet, I was only theorizing about that and studing the various desings. \$\endgroup\$
    – gino
    Commented Oct 23, 2020 at 15:52

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