XLR to Microphone wiring
Originally manufactured as the Cannon X series, by 1950 a locking mechanism was added (Cannon XL)[2] and by 1955[2] a version surrounding the female contacts with a synthetic rubber polychloroprene insulation using the part number prefix XLR. Source: Wikipedia XLR connectors.


The XLR connector is now a standard for balanced microphone connection. In this configuration the microphone capsule is wired to L and R and neither is connected to screen. For an unbalanced microphone one of the mic wires needs to be connected to shield.







simulate this circuit &ndash; Schematic created using CircuitLab

Figure 1 and 2 show how to "unbalance" a balanced microphone for an unbalanced input. Figure 3 shows how to connect an unbalanced mic into a balanced input. (Connect one of the L or R pins to shield in the mic plug.)

The circuit assumes a low-Z microphone feeding into a hi-Z amplifier using a transformer for impedance coupling. The transformer is shown for simplicity but can be effected by electronic solutions.