Electret Microphone Amplifier - MAX4466 with Adjustable Gain
Give your project excellent listening skills with this great value Electret Microphone Amplifier - MAX4466 with Adjustable Gain from PMD Way.
Audio from the onboard 20~20kHz electret microphone is amplified by a Maxim MAX4466 - an op-amp perfect for the job. It has excellent power supply noise rejection for quality scratch-free sound.
Ideal for audio sampling, voice changers, and other audio-sensitive projects that use FFT. A trimpot on the back of the board allows for gain adjustment of a value around 25x to 125x.
At maximum settings this can offer a 5V peak to peak output, however normal values should result with around 1Vp-p.
Using your board:
Connect GND to GND, Vcc to 2.5~5V DC, and the audio waveform is available from the OUT pin.
The output will have a DC bias of VCC/2 so when its perfectly quiet, the voltage will be a steady VCC/2 volts as 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.
Inline header pins are included but not soldered to the board.
For audio-reactive projects, we suggest using an FFT driver library (such as the one in this library) which can take the audio input and 'translate' it into frequencies.
- Download MAX4466 data sheet (.pdf)
- Download electret data sheet (pdf)
- Based on an open-source design by adafruit industries.