Two transistors high gain preamplifier
This is a high gain low signal preamplifier made by two small transistors bc549.Both transistors are direct coupled and have closed loop feedback. T2 realises the amplifiers full voltage gain, T1 merely buffers T2 and operates in emitter follower mode providing a good low output impedance.

It can be used with a small electret microphone or any other low signal.
The image in Multisim shows the amplification and the distortion level, and consumption of the circuit is less than 3mA (no load), the power source from 3v to 16v.