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 2014 issue is indicated as "Vol.37 No.5."

We wrote a long, rather unkind report on the HQD, pointing out that, if that was typical of the way it was supposed to sound (And why not, after Mr. Levinson had installed and tweaked it?), then it had to be the most expensive bomb ever to be made available for civilian use. Mr. Levinson responded with a phone call during which he:

1) Told us we had not heard it at its best, but refused to address himself to our specific criticisms;

2) Claimed that many practicing professional musicians felt the HQD to be "extremely realistic";

3) Informed us that, since he sold very few HQD systems and would soon be discontinuing them anyway because Quad had ceased making those speakers, the "sensible" thing to do would be to kill the report; and

4) Mentioned, just in passing of course, that he was currently writing a feature article for Time on the subject of "underground" audio magazines.