XLR Connectors | page 5

An XLR connector is an individual plug or socket used to assemble or repair a cable, or to fit a device or panel. An XLR cable is a finished lead with connectors at its ends, while an XLR input or output is a socket with a defined function. Shape alone is not enough when choosing: the pin count, male or female format and wiring must all match. In conventional professional audio, three-pin XLR is used mainly for balanced mono signals.

Male, female and pins 1, 2 and 3

A male connector has visible pins, while a female connector has contact sockets. In standard three-pin balanced audio wiring, pin 1 carries the shield or ground, pin 2 is signal positive and pin 3 is signal negative. Do not automatically apply this convention to multipin, power or manufacturer-specific connections. Check the device diagram and the markings on the connector before soldering.

What you are choosing	Typical use	Check before buying
Male XLR	The usual microphone-cable end feeding a preamp or mixer	Pin count and mounting orientation
Female XLR	The usual cable end connected to a microphone	Cable, panel or chassis format
Mini XLR	A compact connection on selected wireless and bodypack equipment	Pin count and exact model compatibility
JACK–XLR adapter	Mechanical connection between different connector types	An adapter does not change signal level or make an unbalanced signal balanced

Why XLR is used for balanced signals

In a balanced connection, two conductors carry the same signal with opposite polarity and the shield follows a separate path. A compatible input compares the two conductors and rejects some interference picked up along the cable. This is still one mono channel, not stereo. A stereo connection therefore normally needs two separate balanced paths, left and right.

From microphone to input

A typical signal path is microphone → XLR cable → microphone preamp, mixer or microphone input on an audio interface. A compatible input can send 48 V phantom power along the same cable to a condenser microphone or another device that requires it. Phantom power is not a feature of every XLR connection and should not be switched on automatically. Mute the channel, lower the gain and check the requirements of both microphone and equipment before connecting.

When to use XLR–XLR or XLR–JACK

XLR–XLR is the natural choice between a microphone and microphone input, or between devices with balanced XLR inputs and outputs. XLR–JACK makes sense when the other device has a compatible 6.3 mm TRS input or output. Changing the connector alone does not confirm matching level or impedance. If you are linking a microphone output to a line input, or a balanced circuit to an unbalanced one, consult the manufacturer's wiring information first; a simple adapter may not be the right solution.