This is a Single-cell microphone amplifier circuit. This circuit produce a voltage gain of 60 dB at 500Ω load with bandwidth 5kHz. This circuit can provide a 60dB gain up to 10kHz if it is unloaded. This circuit has a 10 kΩ input impedance. This circuit cannot neither produce an output swing closer than 800mV or below 150mV to the supply. However this circuit still has a input noise of 40 to 50 nV/√Hz. Here is the schematic diagram of the circuit:

Single cell microphone amplifier circuit schematic

[National Semiconductor]