Triad Magnetics J Series Shielded Audio Transformers feature high-nickel laminations, paper section windings, and a specially tooled shielding enclosure with mu-metal, a nickel-iron soft ferromagnetic alloy with high permeability. These classic transformers were created in the 1950s and are ideal for both new and vintage audio gear, sound processing, and analog studio recording equipment. The J Series offers a shielded audio impedance matching design for a warm signal, while the single-hole mounting enables rotation for maximum hum reduction. Triad Magnetics J Series Shielded Audio Transformers are available in a variety of overall turn ratios and feature a maximum input level of 1mW to 500mW.