FiiO LF-RB Cable: What Does It Connect

By Addicted To Audio - Home Audio Electronics & Accessories | Published: 2026-10-25

Category: How-to Guides

Learn what the FiiO LF-RB cable connects to and how to use its magnetic plug system with compatible devices. Step-by-step guide for IEM users.

Quick answer

The FiiO LF-RB cable connects portable audio sources like DAPs, DACs, and smartphones to IEMs or earphones using its swappable magnetic plug system.

Understanding the magnetic plug system

The LF-RB cable uses a patented magnetic audio plug that lets you swap between 2.5mm balanced, 3.5mm single-ended, and 4.4mm balanced plugs without changing the entire cable. This makes it compatible with most portable audio outputs, but not with full-size headphone jacks or non-detachable cables.

Compatibility considerations

The cable is designed for IEMs and earphones with standard 0.78mm 2-pin connectors. It does not work with MMCX connectors or headphones that use a fixed cable. The plug system fits standard 2.5/3.5/4.4mm jacks, but some recessed jacks on certain DAPs may require a slim adapter.

How to connect the FiiO LF-RB cable

Identify your IEM connector type: Check that your IEMs use a 0.78mm 2-pin connector. The LF-RB cable will not fit MMCX or other proprietary connectors. Common mistake: forcing the pins into a different connector can damage both the cable and the IEM. If your IEMs use MMCX, you need an adapter or a different cable.
Attach the cable to your IEMs: Align the red dot on the left channel plug with the left earpiece and insert firmly until the pins click into place. Repeat for the right channel. Common mistake: mixing left and right channels will invert the stereo image. Always match the colored markers to the correct ear.
Select and attach the correct plug: Choose the 2.5mm, 3.5mm, or 4.4mm plug based on your source device's output jack. The magnetic connector snaps into place automatically. Common mistake: using a balanced plug (2.5mm or 4.4mm) with a single-ended output can cause a short or no sound. Use the 3.5mm plug for standard headphone jacks; use 2.5mm or 4.4mm only with balanced outputs.
Connect to your audio source: Plug the attached plug into your DAP, DAC, or smartphone's headphone jack. Ensure the connection is snug but not forced. Common mistake: inserting a 4.4mm plug into a 3.5mm jack will not fit and can damage the jack. If the plug does not fit easily, double-check the jack type.
Test the audio signal: Play a test track and listen for both channels. If only one side plays, check the cable connections at both ends. Common mistake: a loose magnetic plug can cause intermittent audio dropouts. Tighten the magnetic connection if you hear crackling or one-sided audio.

Product facts

FiiO LF-RB Cable: The LF-RB features an innovative, patented magnetic audio plug design that allows you to easily swap between the included 2.5/3.5/4.4mm plugs. You can switch between balanced and single-ended sources without buying multiple cables, saving money and reducing clutter.
FiiO LF-RB Cable