The FiiO LC-RC is an upgrade replacement cable for MMCX-equipped in-ear monitors, built around high-purity Furukawa monocrystalline copper wire sourced from Furukawa Denki Industrial Co., Ltd in Japan. Designed to replace the stock cable on IEMs such as those in the FiiO FH and FA series, the LC-RC addresses signal clarity from the ground up, using conductor materials and construction techniques typically reserved for considerably more expensive cables.
Furukawa Monocrystalline Copper
The inner conductors of the LC-RC are drawn from Furukawa monocrystalline copper, refined through a secondary process that minimises pores, impurities, and grain boundaries within the copper. Each of the four main strands contains 100 cores of 0.05 mm diameter monocrystalline copper wire, with an additional 20 cores of silver-plated monocrystalline copper at the centre of each strand, giving a total of 480 conductors and a combined cross-sectional area of 22 AWG. More than 70 steps of wire drawing, forging, and treatment are used to achieve the final conductor geometry, with the goal of enabling cleaner, less impeded signal transmission across the audio frequency range.
Coaxial Braiding and German TPU Sheath
The four strands are arranged in a coaxial braid rather than a simple twist, which helps reduce microphonics: the cable noise caused by friction and movement that can be particularly noticeable with IEMs worn during commuting or exercise. The outer sheath is formed from German-sourced translucent TPU material, chosen for its pliability across a wide temperature range and its resistance to yellowing over time.
Expanded MMCX Connectors
At the IEM end, the LC-RC uses expanded MMCX connectors engineered for consistent retention force and straightforward attachment and detachment. The MMCX standard is used across a wide range of IEMs, and the expanded design aims to reduce connector play whilst remaining compatible with the broad MMCX ecosystem.
Modular Plug System
The LC-RC ships with two swappable plugs: a 3.5 mm single-ended plug for use with standard headphone outputs, and a 4.4 mm Pentaconn balanced plug for sources with a balanced output stage, such as portable DAC/amplifiers and hi-res digital audio players. Switching between the two is a straightforward tool-free process, making the LC-RC a practical single cable for multiple sources rather than requiring a separate cable for each termination type.