Mic's usually don't add noise, but the circuit you use to amplify the mic's signal will for sure! Microphones work with a small amount of electrical current, and usually need to be amplified at the mixer to give a usable signal. Try looking at some dedicated microphone pre-amps. All they do is boost a mic's signal with as little extra electrical noise as possible (some also offer EQ'ing and a few effects). Any clicking may be a connection issue. Make sure all your wires and jacks are healthy, and replace as necessary. Hope this helps...