Furutech Clear-Line NCF XLR (M)

Furutech Clear-Line NCF XLR (M): treating an unused balanced input

On a balanced-wired preamplifier or converter, an unused XLR socket remains exposed to vibrations and ambient electrical noise. Furutech addresses this with a passive device designed to fill that gap. The male model plugs into an unoccupied balanced input and combines the brand’s damping material, pure copper pins, and an audio-grade ceramic capacitor. It is sold individually.

A passive device to plug into a free socket

The principle is simple: plug the Clear-Line into an unused XLR socket. No power supply, no battery, no active circuit. The male version has pins, so it mates with a female socket, i.e. an input on the device. A preamplifier, converter, integrated amplifier, or active speaker with several balanced inputs will often have an unused socket: that is where it belongs. The female version is available for the reverse operation, on an output.

NCF material and vibration damping

NCF stands for Nano Crystal² Formula, Furutech’s proprietary damping formula. The body is molded from a liquid-crystal polymer resin combining nylon, glass fiber, carbon powder, and nanometer-sized piezoceramic particles. These particles work through the piezoelectric effect: when subjected to mechanical vibration, they convert it into a minute electrical charge dissipated as heat, reducing the resonances that travel through the connector. The retaining clips are made from the same material. On the male model, this NCF is also injected into the conductive pins.

Stainless steel, carbon, and air chamber

The housing is arranged in layers. A stainless-steel ring selected for its anti-resonance properties surrounds the assembly, combined with the NCF material. Above it are four layers of forged-texture NCF hybrid carbon fiber, protected by a transparent hard varnish. Inside, a semi-sealed air chamber is pressurized to add a damping effect. The end cap, made of heat-resistant nylon enhanced with NCF, completes the resonance treatment and influences tonal balance. Body and shell are secured by stainless-steel security screws, tightened at the factory to the optimal torque and best left untouched.

Rhodium-plated pure copper pins

What sets the male version apart is its pins. They are formed in one piece from pure α (Alpha) copper, copper cryogenically treated and then demagnetized by Furutech, and receive rhodium plating. Rhodium conducts slightly less well than gold by volume, but it resists contact wear better, keeping the connection stable over time. NCF injection into these pins extends the damping work right to the contacts themselves.

A ceramic capacitor to filter noise

Electrical filtering is added to the mechanical treatment. The Clear-Line houses a passive audio-grade ceramic capacitor, whose type and values were determined after lengthy listening sessions. Its function: to attenuate noise coming up through the device terminals. Its outer layer receives a silver-colored damping coating that limits unwanted vibrations. The first connection does not immediately deliver its full effect: a burn-in period of twenty-four hours or more is recommended before forming an opinion.

Technical Specifications

Overview

• NCF Clear Line-XLR (M / Male): reference CF-601M (R) NCF XLR-P
• Line optimizer designed for XLR connectors, sold individually

NCF Material (Nano Crystal² Formula)

• Body made of NCF liquid crystal polymer resin incorporating:
  • Nylon
  • Glass fiber
  • Nanometer-sized crystalline piezoceramic particles
  • Carbon powder
  • Exclusive Furutech NCF anti-resonance damping material
• NCF material properties:
  • Generation of negative ions that eliminate static electricity
  • Piezoelectric effect providing additional damping properties
• Damping clips made from the same NCF material
• Male version (M): NCF material also injected into the one-piece pure α (Alpha) copper rhodium-plated conductive pins

Housing Construction

• Housing ring made of special anti-resonance stainless steel combined with Furutech NCF material
• Housing composed of 4 layers of forged-texture NCF hybrid carbon fiber
• Semi-sealed air chamber: internally pressurized chamber for additional damping effect
• NCF end cap made of heat-resistant nylon combined with Furutech NCF material, for optimal resonance damping and improved tonal balance
• Main body and shell secured with custom stainless steel shock-resistant safety screws, factory-set to the optimal tightening torque

Hybrid Ceramic Capacitors

• Audio-grade ceramic capacitor (passive type) to improve the acoustic performance of equipment
• Type and specifications selected after many hours of testing for optimal sound quality
• Outer layer treated with a high-performance silver-colored damping coating, suppressing unwanted vibrations and improving sound clarity
• Advanced tuning technology eliminating noise interference induced by the equipment’s output terminals

Usage Recommendations

• A burn-in period of 24 hours or more is recommended
• Product screws are fixed: do not disassemble or modify yourself
• The shell pattern may vary from one product to another while retaining the characteristic carbon fiber texture (damping composite material); this does not affect product performance
• Furutech uses non-magnetic stainless steel for certain parts; however, these may exhibit slight magnetism due to manufacturing stresses, without affecting performance