5687W

Premium ruggedized miniature 9-pin high-perveance twin triode featuring massive cathode emission surface areas, engineered to deliver massive peak currents safely in digital computer pulse circuits or ultra-low impedance audio driver stages. Equivalents: 5687, 5687WA, 7119 (similar variant). Real-Life Examples: IBM 704 early mainframe computers, vintage military radar computer sub-grids, high-end custom audiophile preamplifiers and headphone amplifiers.