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Lectrosonics LW and WM Wiring

Lectrosonics watertight transmitters are compatible with our microphones when ordered with the appropriate code. For example, to order a black B6 Omni Lavalier for general speaking, compatible with the WM transmitter, the model number would be: B6W4FF05BWM.

Although the MM400 and WM transmitters have the same 2.5mm input connector, they use very different internal biasing circuits for the microphone. The following table summarizes compatibility between Countryman microphone codes and Lectrosonics watertight transmitters:

Microphone Used with Transmitter Compatibility Notes:
LW code microphone
e.g. B6W4FF05BLW
LW code transmitter
e.g. MM400
Full performance
WM code microphone
e.g. B6W4FF05BWM
WM code transmitter
e.g. WM
Full performance

  • Set bias to 2V for E6/B6/H6
  • Set bias to 4V for all others including B3, EMW, and Isomax Headset
LW code microphone
i.e. B6W4FF05BLW
WM code transmitter
e.g. WM
Reduced performance. Rewire to WM code for full performance

  • Set bias to 2V for E6/B6/H6
  • Set bias to 4V for all others including B3, EMW, and Isomax Headset
WM code microphone
i.e. B6W4FF05BWM
LW code transmitter
e.g. MM400
Potential to damage microphone. Rewire to LW code.

Follow the instructions in the WM User’s Manual (pg. 9) to set microphone bias. If you have any questions or comments, please call us at 650-364-9988, or email us anytime at info@countryman.com.

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