|Internal view of dynamic microphone preamplifier prototype.|
This preamplifier consists with two amplifier stages and initial amplifier is design to get 36dB gain and final preamplifier is used to get 16dB of gain. Preamplifier gain controller is placed in between those two amplifiers and this separation allows reducing clipping in output waveform.
In prototyping stages we test this preamplifier with few 600Ω dynamic microphones with TDA2050 power amplifier. According to our observations this unit produces excellent output with all of these microphones. To get professional results use this preamplifier with 12V battery or with regulated power supply unit and use screened wires for both input and output connections.
Schematic, wiring diagrams and PCB design of this microphone preamplifier are available to download at elect.wikispaces.com.