13 June 2026 | 5 min read
What is phantom power, and when do you actually need it?
It is a DC voltage sent up the same cable that carries your audio. Simple idea, several ways to get it wrong.
Phantom power is a direct current supply, normally 48 volts, sent from a preamp to a microphone along the same balanced cable that carries the audio signal. It is called phantom because a microphone that does not need it should not notice it is there.
Which microphones need it
- Condenser microphones: the capsule needs a polarising voltage and the internal impedance converter needs power.
- Active ribbon microphones: the built in preamp needs the supply, though the ribbon element itself does not.
- Most phantom powered lavalier and shotgun mics used on set.
Which microphones do not
Dynamic microphones generate their own signal and need nothing. A correctly wired balanced dynamic will not be harmed by phantom power, because both signal pins receive the same voltage and the difference across them stays zero.
Where it goes wrong
- Passive ribbon microphones can be damaged if phantom hits them through a miswired cable or an unbalanced patch.
- Unbalanced connections and TRS patchbays break the symmetry that makes phantom safe.
- Hot patching, plugging in while phantom is on, causes a loud transient and can stress a capsule.
The battery question
Phantom is the single largest power draw in most bags. Each channel can pull up to 10 mA at 48 V, and eight channels of that adds up quickly. Many field mixers offer 12 V phantom for mics that accept it, which is a real saving on a long day.
Plug in power is not phantom power
Small 3.5 mm microphones on cameras and recorders use plug in power, typically 3 to 5 volts on an unbalanced connection. It is a different standard. Feeding 48 V to a plug in power mic, or the reverse, gives you either silence or damage.