Want to use a small Microphone preamp with low voltage
supply? Just three “AAA” cells give you more current and lasts longer than
a 9v Batt.
This an easy-to-assemble circuit with an LM 158/358 or other better op-amp
of your choice with a wide gain adjustment for your need.Use a 9v Batt.supply. You must take
care to adjust the gain so as not to distort the output. The microphone used is
a Mini-Condenser Mike Element from Radio Shack ARCHER No 270-085.
The circuit below is a complete circuit for use as a powerful microphone amplifier with a gain of up to 4000.