12 volt power supply

Invented in the mid-1960s and standardized shortly thereafter, phantom power is a widely-used method for supplying current to devices over signalling cables, especially audio. This is most often used for condenser microphones, and occasionally microphones of other types.

Phantom power supplies are often built into mixing desks, microphone preamplifiers and similar equipment. Many active DI boxes also use it. 12 volt power supplies,12 volt power supply catalog, AC, DC and DC/DC 12 volt power supplies, DC to DC Converters, and ATX power supplies. In addition to powering the circuitry of a microphone, in traditional (DC-polarized) condenser microphones the phantom powering directly or indirectly supplies the voltage used for polarizing the microphone's transducer element ("capsule").

Phantom powering consists of direct current applied equally through the two signal lines of a balanced audio connector (in modern equipment, usually an XLR connector). The supply voltage is referenced to the ground pin of the connector (= pin 1 of an XLR), which normally is connected to the cable shield and/or a ground wire in the cable. Thus the same type of balanced, shielded microphone cable which studios already used for dynamic microphones could also be used for condenser microphones — in contrast to vacuum-tube microphones, which had required special, multi-conductor cables of various kinds.