Electret Microphone Amplifier MAX4466 with Adjustable Gain Add an ear to your project with this welldesigned electret microphone amplifier. This fully assembled and tested board comes with a 2020KHz electret microphone soldered on. For the amplification we use the Maxim MAX4466 an opamp specifically designed for this delicate task! The amplifier has excellent power supply noise rejection so this amplifier sounds really good and isn't nearly as noisy or scratchy as other mic amp breakouts we've tried! This breakout is best used for projects such as voice changers audio recording/sampling and audioreactive projects that use FFT. On the back we include a small trimmer pot to adjust the gain. You can set the gain from 25x to 125x. That's down to be about 200mVpp (for normal speaking volume about 6 away) which is good for attaching to something that expects 'line level' input without clipping or up to about 1Vpp ideal for reading from a microcontroller ADC. The output is railtorail so if the sounds get loud the output can go up to 5Vpp! Using it is simple: connect GND to ground VCC to 2.45VDC. For the best performance use the quietest supply available (on an Arduino this would be the 3.3V supply). The audio waveform will come out of the OUT pin. The output will have a DC bias of VCC/2 so when it's perfectly quiet the voltage will be a steady VCC/2 volt (it is DC coupled). If the audio equipment you're using requires AC coupled audio place a 100uF capacitor between the output pin and the input of your device. If you're connecting to an audio amplifier that has differential inputs or includes decoupling capacitors the 100uF cap is not required.
