Much has been written about the divide in high-end audio between subjectivists, who trust their ears, and objectivists, who believe that anything not scientifically proven is fake news. I respect both sides and am skeptical of both extremes, and I like to think that's how most audiophiles feel. High-end audio is about experiencing music—that's the whole point—but scientific and technological rigor lie behind every real advance, past and future. I regret the cynical snake-oil salesmanship, bad thinking, and clumsy engineering that pervade certain parts of our hobby.

Every day in my bunker, I use one of a few high-quality headphone amplifiers to double as a line-level preamplifier-controller and operate as the quality-assurance reference for my ongoing audio experiments. I must choose this component carefully, because it determines the upper limit of my system's ability to reveal any subtle differences among components under review.