An Excessive Amplifier, the Pass Labs Xs
Pass Labs’ engineer Wayne Colburn insisted that the name of their latest amplifier, the Xs, was not a pun. He spent over an hour detailing the 3-year design project that culminated in the company's $85,000/pair, solid-state, two-chassis-per-channel, class-A amplifier. Leaning on the 4.5-foot stack of the amplifier's stereo configuration, Wayne spoke about how the design was based on the results of an examination of transfer characteristics of a diverse set of gain devices, including tubes and SITs (silicon-carbide devices that are exclusive, we believe, to Pass Labs for use in audio). The output stage was designed to reproduce the transfer characteristics preferred by a panel of listeners, who lived with a variety of different output stages for a lengthy period of time.