how much is the dynamic impedance/resistance seen from a electret microphone? I am trying to design a microphone preamp and need to know seen resistance in small signal from the signal source (microphone in this case). This is very important because I should match poles and zeros so they will disable each other.
Pretty much the normal rule is that the output impedance is the bias resistor. This is because the output is usually a jfet's drain and in normal bias configurations for a jfet it operates as a high compliance output hence output impedance is largely dictated by the external bias resistor.