A standard method of supplying DC voltage, typically 48 volts, through a balanced audio cable, usually XLR, to power condenser microphones and certain audio devices. For example, condenser microphones require an external power source to operate. Phantom power provides this through the same cable used for audio transmission, eliminating the need for additional batteries or external power supplies.
Voltage and Delivery: The standard phantom power voltage is 48V, though some devices may use lower voltages (12V or 24V). The power is sent through the audio cable in a way that evenly distributes the voltage across both signal conductors (pins 2 and 3 in an XLR connector), with the ground (pin 1) as the return path. This balanced delivery prevents interference and maintains the audio signal’s integrity.
Balanced Signal Transmission: Phantom power only works with balanced connections, where two signal lines carry the same signal in opposite polarities. This design inherently cancels out noise picked up along the cable’s length, ensuring a clean audio signal even with the additional power.
Compatibility: Since phantom power operates through both signal conductors, it does not affect dynamic microphones or other devices that do not need it, as they don’t use the voltage. However, phantom power can potentially damage ribbon microphones if they’re not designed to handle it, so caution is advised.
Control: Many audio interfaces, mixers, and preamps provide a dedicated “phantom power” switch, often labeled as “+48V,” allowing users to enable or disable it depending on the microphone type in use. Typically, phantom power is switched on only when using condenser microphones.
Phantom power is standard in studio recording, live sound setups, and broadcasting, where condenser microphones are frequently used for their sensitivity and accuracy in capturing detailed audio.