There are thousands of pre-amplifier circuits. These are three which have interested me and are a little different.
Intercom preamp A very convenient way of making an intercom is to use a loudspeaker as a microphone.
This is a preamp with a low input impedance suitable for this purpose. The circuit is so simple that there is little to say about it, but it gives very good results. Tr1 is operated in grounded base mode with input to its emitter to give low impedance input. The values shown give correct operation from 9v. If operating from other voltages you may wish to alter the 1K8 resistor to give symmetrical clipping at high levels.