If you’ve ever done anything on the professional side of audio, you’ve probably run into a condenser microphone. These require power to work. Sometimes, that’s a battery you put into the mic. Sometimes it’s a separate dedicated power supply with a special multi-pin cable.
But most often these microphones use phantom power. This is power delivered by a mixer or console, which uses the same cable that the audio comes back on. Hence, the idea phantom because the cable is doing two things and the power seems to be delivered by magic.
Phantom power is set up to run on shielded balanced lines, because it uses both the twisted pair and the shield as the DC power delivery. Unbalanced microphones, therefore, cannot use this system - at least not as it is described below. Read more