(n.) An audio connector used for most low-impedance microphones and for balanced lines between professional signal-processing equipment. Three wires are soldered to three pins inside the barrel of the connector. The ground wire or the shield is typically connected to pin 1. Pins 2 and 3 carry the same signal in equal strength, but with a reversed phase relationship. This allows for the cancellation of unwanted noise over long cables. The microphone lines used in most recording studios are 200-ohm balanced lines with the shield grounded only at the preamp end. If the shields are grounded at more than one point, a ground loop may be created, producing a 60-cycle hum.
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