FR-7f

About the FR-7f

The Fidelity Research FR-7f is an improved version of the FR-7 MC cartridge, featuring a unique push-pull power generation method with a magnetic circuit consisting of two magnets and four poles. This design allows power generation at four points, producing a sufficiently large output voltage even with a low impedance coil. Unlike conventional designs that generate cancellation currents, the FR-7f's magnetic circuit outputs positive signals even in cancellation regions, improving phase and crosstalk characteristics, electrical conversion efficiency, and output power. It uses samarium-cobalt magnets, which have high coercivity and resistance to self-demagnetization, maintaining magnetic circuit characteristics over time. The power generation coil is a fully air-core coil without a winding frame, eliminating distortion from moving magnetic materials and reducing the effective mass of the vibrator to about two-thirds, lowering mechanical impedance at high frequencies. The stylus tip is a specially polished 0.15 mm square refined contact solid diamond needle. The cartridge body is mounted on a machined aluminum block base, with minimized shell flat surfaces and short, thick lead wires for durability and signal integrity. It weighs 30 grams and is designed for heavy tonearms with high effective mass. The FR-7f was originally priced at approximately 77,000 yen in 1980 and is highly regarded for its sound quality and durability, with the ability to be retipped and serviced over time.