Lectrosonics 21750 XLR Barrel Adapter For Polarity Reverse

The Lectrosonics 21750 is a polarity-reversing XLR barrel adapter designed for audio engineers and wireless system operators who encounter phantom power startup failures when pairing certain condenser microphones with Lectrosonics UH400-series or HM transmitters. The adapter swaps pin 2 and pin 3, correcting for the asymmetrical current draw that some P48-powered condensers require to initialize properly.

This adapter is particularly relevant when integrating older Neumann 100 Series microphones, Rode NTG3 shotgun mics, or similar condensers into a Lectrosonics wireless chain. Rather than replacing equipment or modifying the transmitter, the 21750 inserts inline between the transmitter and microphone, providing an immediate hardware fix without any signal processing overhead. It is also noted as compatible with the Earthworks M30 when used with HM or UH400a/TM configurations.

For production teams and engineers maintaining diverse mic inventories across theatrical, broadcast, or location sound applications, the 21750 eliminates guesswork when a microphone fails to power on correctly through a Lectrosonics transmitter. Its compact barrel form factor adds no bulk to the signal chain and requires no tools or configuration.