The hoary question of tubes vs transistors, once certain and clear, is made ambiguous by recent products from a few solid-state specialists, not the least being Ayre Acoustics—the company that endures in the wake of the passing of its founder, the widely admired Charley Hansen. In their solid-state preamplifiers and amplifiers of the past decade in particular, Ayre has enshrined a number of technologies that are more than just variations on the audio-engineering status quo, and that appear to pay real sonic dividends.

I got an e-mail last summer from my colleague Tyll Hertsens, editor of our InnerFidelity website. "Recently reviewed and really liked the new MrSpeakers Æon," he wrote. "They're a little rough-sounding as sealed headphones tend to be, but the tonal balance is superb. I got three in for review to make sure they're consistent. After measurements I asked [MrSpeakers'] Dan Clark if I could forward them to you because I like them so much and thought you should hear them. . . . I really think you may enjoy them."