Stereophile and Music Hall Audio share a long mutual history. Like most relationships, it's had its ups and downs; unlike most relationships, this one is well documented—in retired writer Sam Tellig's much-loved "Audio Cheapskate" and "Sam's Space" columns, and Music Hall Audio proprietor Roy Hall's responses in "Manufacturers' Comments." I always found Sam and Roy's gentlemanly brawling to be good, clean, if occasionally uncomfortable fun—like the touchy rapport between a gregarious dog and a rascally cat forced to live under the same roof: A truce may have been called, but don't expect them to make nice.

Approximately 33¹/₃ years after AudioQuest's first phono cartridge, the company announced two new USB D/A headphone amplifiers: the DragonFly Black ($99) and the DragonFly Red ($199). Both have circuits designed by the engineer responsible for the original DragonFly—Gordon Rankin, of Wavelength Audio—and both have the novel distinction of requiring considerably less operating power than their predecessors, so much less that the new DragonFlys can be used with iPhones, iPads, and various other mobile devices.