Unplugging a condensor mic powered up at +48V is a very bad thing. The microphone itself is a capacitor. When a cap has voltage removed from it, the cap discharges. This is called "back Electro-Motive Force". The voltage discharged by the cap is reversed in polarity. In a "balanced" configuration, the Op-amp only amplifies the DIFFERENCE between the voltages present on both input pins. When you unplug the mic, if you open the circuit fast enough, and open both pins at exactly the same time, the op-amp ,most likely, will not be harmed . But, if you open one pin while the other pin is connected, even for a brief instant, the difference between the two input pins to the op-amp will be HUGE. The discharge from the condensor will follow this path amd *BAM*. Goodbye op-amp, possibly blowing the condensor element. Technically, you should turn off the phantom power and wait at least one minute for the PS and the condensor element to discharge. I wait two. Why take a chance for one to two minutes of your time?