Radial LX-3 User Guide
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Using The LX-3™

The LX-3 is a balanced line-level splitter designed to take a mono audio signal and split it to three destinations simultaneously. Premium-quality Jensen® transformers provide isolated outputs while maintaining pristine audio quality, allowing you to split your signal without buzz or hum from ground loops. For complete details on the LX-3, please click on the icon to the left to download the user guide.

Making connections

Before making connections, ensure that your sound system is turned off and all volume controls are turned down. This prevents any plug-in transients from damaging speakers or other sensitive components. The LX-3 is completely passive, so it doesn’t require any power to operate.

The LX-3 has a combination XLR/TRS input connector, which is wired with the AES standard pin-1 ground, pin-2 hot (+), pin-3 cold (-). You can connect balanced or unbalanced inputs to the LX-3; the isolated outputs will always be balanced signals, while the direct output can be balanced or unbalanced depending on the input source.

The input pad

Should you have a particularly hot input signal that you are sending to the LX-3, you can engage a -12dB pad to knock down the signal and prevent distortion. This is done using the PAD switch, and will affect the output of the direct output LX-3, as well as both isolated XLR outputs. Should you wish to reduce the level at the isolated outputs, but keep the direct output at the level of the original signal, there is an internal jumper that you can adjust to accomplish this.

To change the operation of the PAD switch, so it doesn’t affect the direct output, follow these steps:

  • Use a hex key to remove the four screws that secure the cover of the LX-3.
  • Slide the cover off the LX-3, and locate the internal jumper as indicated on the photo below.
  • Move the jumper over to connect pins 2 and 3, this will allow the THRU output to bypass the PAD.

Using the ground lift

When connecting two or more powered devices, you may encounter hum and buzz caused by ground loops. The isolated outputs on the LX-3 have a Jensen® transformer in their signal path, which blocks DC voltage and breaks the ground loop. However, the direct output is connected straight through to the input of the LX-3, and you may need to engage the ground lift on this output to disconnect the audio ground and help remove buzz and hum on this output. Ground lift switches are also present on the isolated outputs to provide further abatement of ground loop noise.

The image above shows an audio source and a destination with a common electrical ground. As the audio also has a ground, these combine to create a ground loop. The transformer and ground lift work together to eliminate the ground loop and potential noise.