Microphones are sensitive, they don’t always produce powerful signals. Preamplifiers can take any microphone signals and boost them. One of the first things to think about when looking for a microphone preamp is what kind of mic will be used. For example, condenser microphones usually require a source of phantom power. On the other hand, dynamic microphones produce a weaker signal than condensers. So, for dynamic mics, a preamp with high gain and low noise is essential. That’s just one example. Look for dual channel, multi-channel amplifiers online at Delhi Sound Store.