4. Phantom Power

The term "phantom power" might sound a bit mysterious for beginners, but it's actually straightforward. Phantom power refers to a supply voltage that's present on both wires (a shared positive pole) of a balanced cable with continuous shielding (negative pole). Phantom power is used to supply voltage to condenser microphones or active DI boxes so that they can operate without batteries.

Since the voltage potential (usually +48 V) on the two wires doesn't differ, the voltage is "invisible" to devices that don't access it via the wires and shielding. Hence, the term "phantom power." Not all devices that don't need this voltage can be connected to a system with activated phantom power without risk of damage. For instance, ribbon microphones might get damaged. That's why fans of ribbon mics who also want to use condenser microphones powered by phantom power should ensure that their chosen analogue mixer doesn't just have a global phantom power option but also allows for channel-wise activation. If not, it's better to feed unbalanced signals via designated line inputs or through interposed DI boxes instead of using XLR connections.