Aleph 5

About the Aleph 5

The Aleph 5 is a classic stereo amplifier from Pass Labs, designed by Nelson Pass. It features a simple two-gain-stage topology with pure single-ended Class A operation, resulting in a direct signal path and minimal distortion. The amplifier uses MOSFET output devices and a patented current source topology, optimizing performance across a wide range of speaker impedances. The Aleph 5 is known for its harmonic richness, midrange bloom, and smooth yet detailed high frequencies, often compared favorably to high-end tube amplifiers. It runs very hot and requires ample ventilation. The build is robust, with a large toroidal transformer and substantial filter capacitance. The back panel includes both single-ended RCA and balanced XLR inputs, as well as gold-plated binding posts. Pass Labs offers factory support for all Aleph series amplifiers.