Parasound Halo A 21+

POWER AMPLIFIER

- KALMAN RUBINSON

The components I needed to choose for my first system were never in doubt: a turntable or record changer, an integrated amplifier, and a speaker. One of each, please, in those mono days.

Today, even in stereo, that trinity would be regarded as rather traditional—or, if you prefer, purist. Digital has exploded the range of source options and loudspeaker options. Yet amplifiers have not changed much in how and what they do. They take an analog voltage signal from the source, increase it, and back it up with enough current so that the output can power a relatively insensitive device, the loudspeaker. Amps still do the heavy lifting, and that includes today’s popular class-A, class-AB, and class-D power amplifiers, none of which involve any digital operations. These being mature technologies, particularly for traditional-technologies amps, new power amplifiers inevitably compete with their predecessors as well as with their contemporaries. This is evident with the release of the new Parasound A 21+ stereo power amp ($3150), the successor to the A 21, which was originally launched in 2003.

Parasound was founded in 1981 by Richard Schram, and the company has been offering audio products under their own name as well as for OEM sales since then. Parasound has established close and long-term relationships, some spanning more than three decades, with contract manufacturers in Taiwan, which are responsible for the manufacturing. In 1988, Schram enlisted the services of circuit designer John Curl, and he brought along designers Carl Thompson and the late Bob Crump, forming a team whose work resulted in the development of Parasound’s flagship Halo line. Halo products have consistently been praised by Stereophile and, over the years, their circuits and technologies have migrated into other Parasound products.