Masisira ba ng Phantom Power ang aking MICROPHONES?
Phantom power or +48V DC seems like a high enough voltage to do some serious damage to microphones that don’t need it (like ribbons and dynamics). Some people shut phantom power off when plugging and unplugging condenser microphones as well. The truth of the matter is that in practice the chances of damaging a condenser microphone because it was unplugged or plugged while phantom power was on, is absolutely none. Of course if you are used to shutting it off, every time you plug a mic in, there’s nothing bad about it. For the 1 in 10 millions or so chance of it actually damaging a condenser mic keep following your routine.
When it comes to dynamic mics. I’ve yet to see one that actually requires phantom power, so if you have the choice to send phantom power to a dynamic mic, don’t do it. Again the chances of damaging a dynamic mic with phantom power are very slim or rather none unless we have wiring problems.
You don’t really need to know electronics to understand the following diagram:
Phantom power is usually 48V DC at very low current (usually micro amps up to a few mili amps), which is sent to pins 2 and 3 of the XLR plug through the resistors R1 and R2. Which means that there’s 48 volts between ground (pin1) and pin2 and also between ground (pin1) and pin3. Which automatically means there would be exactly 0 volts between pins 2 and 3. In fact the resistors R1 and R2 are always exact 1% tolerance resistors so that the difference between the potential of pins 2 and 3 is exactly 0 volts. As you would notice on the microphone side the dynamic coil or in the case of a ribbon they would be connected between pins 2 and 3. Since the voltage between pins 2 and 3 is zero the coil or the ribbon would not even “know” there’s phantom power applied to it. Since the ground in any dynamic or ribbon mic is simply connected to the body of the mic and has nothing to do with the coil or the ribbon inside of it, the coil is not affected by the 48 Volts between ground and pin 2 nor the 48 volts between the ground and pin 3.
The real danger is if you have a ribbon mic without a built in isolating transformer (most modern ribbon mics have their ribbons isolated either electrically or with a transformer) connected with a bad cable which happens to have pin 1 shorted to either pin 2 or pin 3, which brings the potential of one of those pins to 0 and in comparison to the other not shorted pin we end up with 48V between pins 2 and 3. Practically that would be the only condition where Phantom power could damage the ribbon. Theoretically, this scenario would damage a dynamic mic too, but in practice the current of the phantom power is low enough so that even if it flows through the coil it wouldn’t inflict any permanent damage to it, but either way don’t try it at home, or the studio.
enjoy!
jojo
