CD Player/Transport Reviews

Engineering, as expressed by great audio designers, frequently bridges the gulf between science and art. Some audio products can be better understood as expositions of sound reproduction techniques than as clear expositions of scientific principles. But the achievement of a high artistic standard for audio equipment is gauged by sound quality, not design principles.

A component that by received standards has a weak technological base may nonetheless perform well, even outstandingly, when executed by a good designer. "This can't be done!" exclaim science-based diehards. "Look at the inferior test results!" Yet the evidence of our own ears shows that it can. Many reputable CD players have apparently humble technological origins, even remarkably low-cost platforms. On the other hand, some demonstrate nearly flawless, high-tech execution of the best science available, yet still fail to make the grade on music. (There are, of course, those few components that measure well and sound superior.)

Our knowledge base is incomplete in this area, and speculation is dangerous. Nevertheless, it's worth exploring. A CD player's output stage resembles a preamplifier's line stage. On top of the effort involved in creating the digital circuits, the designer of a CD player therefore has to provide the equivalent of a great preamp, since without that stage we will never hear how good the intrinsic digital section might be. (When you think of the wide spectrum of sound quality available from preamplifiers, remember that these often costly and elaborate designs don't have to process the ultrasonic signals emanating from a CD player's D/A converter.)

It's fair to say that many carefully engineered CD players marketed today fail to properly involve and entertain listeners because of their inadequate analog stages. You could also say that if an audio manufacturer produces a broad line of electronics that does not contain a really good preamp, that manufacturer is unlikely to produce a really good DAC or CD player.

Given our present state of knowledge, the analog section of a CD player is very likely to be more important to a player's sound quality than the digital section. This contradicts the extensive promotional hype concerning effective bit resolution, re-sampling rates, digital filter ripple, balancing in the digital domain, etc. I would not presume to say that such details don't matter; however, their subjective weight is often blown out of all proportion.

To quote examples, there are significant manufacturers who have succeeded in the CD-player field with relatively inexpensive, "low-tech," older-generation transport and digital technologies. These include Naim, Conrad-Johnson, and Audio Research—all of whom have proven track records in producing fine preamplifier analog stages—and now Exposure Electronics as well.—Martin Colloms