Condenser microphones, both small and large diaphragm, require additional power to operate. Ribbon and dynamic microphones do not. This extra boost of juice is referred to as "phantom power", often notated on equipment as "48V", which represents the 48 volts of DC power that charges the microphone's diaphragm and internal amp. Without it, your microphone will not be able to pick up or put out signal.
When connecting your condenser microphone to a cable, make sure that phantom power is off. This will prevent power surges or pops, which could damage your speakers from the sudden burst of energy. Once your microphone is plugged in, then apply phantom power. From here, you can adjust the gain until you get an adequate signal for your recording purposes. Phantom power should be turned off before unplugging your microphone.
In order to connect a condenser microphone to a computer, you will need to use an interface that provides phantom power. If you are using a single condenser microphone, MXL's Mic Mate Pro converts the microphone's XLR analog output into a digital signal that's transmitted via USB, while also providing phantom power. Additionally, it gives you gain control and a headphone output with volume control for direct input monitoring. It is important to note that not all XLR to USB adapters provide phantom power, so be sure that your adapter does this.
An interface works similarly, utilizing a microphone preamp that provides phantom power, but can provide more flexibility in connections, monitoring and signal routing options. Some interfaces can have up to 8 input channels to accommodate multiple microphones at once. Most interfaces will connect to your computer with common USB or Thunderbolt connections. Don't forget to select your interface as your input and/or output device in your recording software or computer settings.
USB microphones do not need phantom power. Your computer will provide enough power through the USB connection to charge the microphone and operate correctly. An interface is not required to use USB microphones as everything is built into the mic itself.
Dynamic microphones are (usually) passive, meaning they do not have any active electronics which require additional power. Mistakenly using phantom power on a dynamic microphone will not damage it, though it should be avoided if possible. Some mixers or preamps provide phantom power to groups of channels instead of individual channels, meaning your dynamic mic might receive phantom power. This should not be cause for concern.
Ribbon microphones should not be used with phantom power. While accidentally and momentarily exposing your ribbon mic to 48V may not have a negative effect, prolonged exposure could stretch or completely blow a ribbon element. This will greatly diminish your microphones ability to operate. There are some active ribbon mics which do require phantom power, to which these rules do not apply.
Tube microphones require more than 48V to operate and typically come with their own dedicated power supplies. Phantom power is not required on the channel where you connect your tube microphone.
If your mixer or interface does not provide phantom power, you will need an external 48V power supply. This should be used with an interface or preamp that gives you gain control in order to adjust the amount of signal from your microphone once it’s powered.
NO (powered by computer)
NO (tube mic with external power supply)