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Filmmaking Dictionary: Number 4 / 48V Phantom Power (P48)
Definition
48V phantom power, often called P48, is a method of supplying DC power to compatible microphones through the same balanced connection that carries their audio. Mixers, recorders and microphone preamplifiers commonly provide it.
It is often required by condenser microphones and some active devices. It is not an audio level, a battery capacity or a general-purpose camera power supply.
How the Connection Works
In a standard balanced three-pin XLR arrangement, the nominal phantom voltage is applied equally to the two signal conductors relative to the reference conductor. It is not intended as a 48-volt difference between the two audio signal pins.
This arrangement allows compatible microphone electronics to receive power while the balanced audio path carries the wanted signal. The microphone draws the current it needs within the supply’s supported limits.
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Check the Microphone
Some microphones require P48, some can operate from other power sources, and others do not need phantom at all. Active ribbon microphones may require power, while particular passive ribbon or unbalanced arrangements need different handling. Follow the microphone and interface specifications.
A correctly wired balanced dynamic microphone normally does not require phantom power. That does not make every improvised adapter or damaged cable safe to use with power enabled.
Phantom Versus Plug-In Power
The low-voltage bias used by many small lavalier or camera microphones is not interchangeable with 48V phantom. A passive connector adapter does not necessarily convert one powering method into the other. A suitable interface may need electronics to supply the microphone correctly.
Practical Example
A boom microphone produces no signal after being connected to a recorder. Before increasing gain repeatedly, the sound recordist checks the microphone’s power requirement and the input’s power setting. The same check includes the cable, routing and whether the channel is configured for the intended input type.
Connection Checks
- Confirm the microphone’s supported power method.
- Use the correct balanced cable and approved adapters.
- Reduce monitoring levels or mute the path while changing connections as appropriate.
- Enable power according to the equipment’s connection procedure.
- Allow the microphone to settle and check the recorded signal.
- Account for powered microphones when planning recorder battery use.
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Frequently Asked Questions
Does phantom power make a microphone louder?
It powers compatible circuitry. Gain and microphone sensitivity determine signal level.
Can any XLR connector supply P48?
No. The port must be designed to provide it; connector shape alone does not establish that function.
Related Terms
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