This mic preamp uses the low noise IC uA739. The circuit is an example of how a good preamplifier can be designed for dynamic microphones. The IC houses two identical integrated preamp circuits. The ...

Here is an Electret Condenser Microphone – ECM preamplifier circuit based on ultra low noise BC650C transistors. Due to difficulty of finding BC650C, instead of them, as you can see in the schematic, ...