Stereophile Review, Pass Labs XA60.8, Jim Austin, November 22, 2017
Nelson Pass said in my interview with him in the September 2017 issue. He noted how his First Watt experiments with amplifiers based on static-induction transistors (SITs) led to an insight into the subjective effects of second-harmonic distortion, particularly its phase, and in turn influenced his design of his big Pass Labs amps. "The SIT being very much like a triode, it is easy to make a single bias adjustment which affects the second harmonic distortion of the device, ranging from a relatively large amount [of] positive phase second [harmonic] through a null point with no second [harmonic], to large, negative phase second-harmonic distortion," he said. "Negative-phase second harmonic tends to expand the perception of front-to-back space in the soundstage, separating instruments a bit. Positive phase does the opposite, putting things subjectively closer and 'in your face.'"