Components listed here have been formally reviewed in Stereophile and have been found to be among the best available in each of four or five quality classes. Whether a component is listed in Class A or Class E, we highly recommend its purchase.

Each listing-in alphabetical order within classes-is followed by a brief description of the product's sonic characteristics and a code indicating the Stereophile Volume and Issue in which that product's report appeared. Thus the May 2015 issue is indicated as "Vol.38 No.5."

In the 1952 edition of the Radiotron Designer's Handbook, long recognized as the "bible" of the industry, the permissible level of IM distortion for a high-fidelity amplifier was given as 3%, with the alternate figure of 2% being cited as a "rather extreme" specification. We wonder what the author of that statement would think of today's solid-state amplifiers with their measured IM of 0.01% and less. And we wonder what he would think about the fact that these super-amplifiers still have audible distortion.