FRT-4

About the FRT-4

The Fidelity Research FRT-4 is a highly regarded vintage step-up transformer (SUT) designed for moving coil (MC) cartridges, featuring separately encased toroidal transformers for each channel in a steel box with aluminum casing. Produced by Fidelity Research (1964-1984, Tokyo), it offers exceptional sound quality with extended treble, agile dynamics, transparency, and versatility for MC cartridges with coil impedances from 3Ω to 40Ω. It outperforms models like the FRT-3 and compares favorably to the Stevens & Billington TX103. Includes 3 switchable inputs and a bypass option. Internal resistors (18kΩ across secondary, 1MΩ partial) can be modified for sonic optimization. Recommended for pairing with phono preamps having 47kΩ input impedance, allowing optimal matching via adjustable primary load (10x-20x cartridge coil impedance).