Adafruit Electret Microphone with Built-in Amplifier - Adafruit 1713, The Adafruit Electret Microphone AGC Amplifiers feature a built-in microphone and use the MAX9814 microphone amplifier. The amplifier's automatic gain control will reduce loud sounds and amplify the quiet ones to minimise volume related distortion. You can configure the maximum gain to 40, 50 or 60dB and the Attack/Release ratio to 1:4000, 1:2000 or 1:500 via jumper settings.The amplifier's output is approximately 2Vpp with a 1.25V DC bias making it suitable for sampling with a 3.3V analogue to digital converter (ADC) without the need for a blocking capacitor. However, if you want to connect one to a Line Input then use a blocking capacitor of between 1 and 100µF unless you have a differential amplifier or it already has its own blocking capacitor.Get started quickly using Adafruit's tutorial for this board showing how to wire one up to a set of headphones. Having mastered that, you can move on to connecting one to a