I thought this circuit was clever so I'm sharing:

electret microphone circuit with fet bootstrap

The JFET current source is bootstrapping the electret and thereby providing 20dB of linearized gain. The bootstapping network also provides for some frequency shaping and the output is buffered.

So this isn't really a question but criticism is welcome. How would you improve this circuit?

  • \$\begingroup\$ This electret has a built-in JFET, right? \$\endgroup\$ – endolith Oct 6 '15 at 17:41
  • Positive feedback from the output increases output impedance and load sensitivity. Add a voltage buffer to the output to more predictably drive a wide variety of loads or cable lengths.

  • See this awesome appnote for more than you ever wanted to know about JFET biasing.

  • See also the SRPP/mu-amp/whatever circuit for further inspiration.

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