Esoteric P-2 CD transport
The argument that CD transports absolutely cannot affect the sonic characterproposed, I might add, by engineers who reject the idea on a strictly theoretical basis without ever listeninggoes something like this:
"Bits is bits. If the ones and zeros are the same, there can be no difference in the analog output signal. Higher-precision drives and laser mechanisms make no difference because the system must distinguish between only a one and a zero. There are no intermediate values. Even if the signal recovered from the disc at the photodetector is cleaner and has less jitter (timing variations) with a better transport, it is irrelevant because that signal is squared, buffered, decoded, and clocked out of another buffer with quartz-crystal accuracy. Any timing variations are removed by the buffer, eliminating jitter from the list of the audiophile's sonic gremlins. Now, since the data are identical, and jitter is not a factor, what's left as a source of the difference? And even if there were some slight differences in the datastream, how could that affect something like soundstage depth? Those naïve audiophiles who believe such things don't realize that digital either works perfectly, or doesn't work at all: the variability associated with analog has been removed by digital's perfection. Your computer doesn't perform differently when you run a copy of a program rather than the original program disc."
This way of thinking was reflected in a recent Pro Sound News article about CD tweaks. Here are some quotes from engineers at CD manufacturing plants: "It's black magic" (Jim Boyer, American Helix). "Lasers read a straight binary code. That's zero and one every time. It doesn't matter what color the disc is, the laser still will not read one and a half. CDs are like typewriter keyboards. When you hit M, it always comes out M" (Scott Bartlett, Digital Audio Disc Corporation). "There's just no scientific credibility surrounding these activities" (Joe Robinson, Philips DuPont Optical). "It's a gimmick" (Dave Williams, Nimbus Records). However, one representative from Disctronics, Ramin Ghadimi, did go way out on a limb and speculate that "The same CD may sound different in a different player" (footnote 2).
During the past year, I've had some fascinating discussions with designers of well-respected high-end digital converters and CD players. Of particular interest to me is the question of how jitter and noise in the recovered HF signal could propagate through the buffers and decoding circuitry to affect the transport's S/PDIF output, much less the analog output signal. This interest was sparked by my experiences with the Esoteric P-2 transport. I heard a significant improvement in the musical presentation with the P-2 and, perhaps not coincidentally, measured much lower jitter in its HF signal than that measured in other transports (footnote 3).
None of the designers with whom I spoke knew the answer to how variations in the HF signal could possibly get through to affect the analog output, yet all heard differences when the HF signal was changed. The collective attitude was, "Our charter isn't to do basic research into these things. We don't have dozens of engineers to figure it out. Building good-sound products is our business, and if cleaning up the HF signal results in better sound, we're going to do it despite the lack of a theoretical basis." Many of these designers, I should add, have advanced engineering degrees (footnote 4).
This brings us to the Esoteric P-2 CD transport, a $4000 product that represents a complete rethinking of CD transport design. What are the musical effects of this radically different drive mechanism? How important is the transport to CD playback?
The Esoteric P-2 is the matching transport to the D-2 digital converter reviewed in Vol.13 No.10 (along with Esoteric's two other converters). Priced at $4000, it represents the top of the Esoteric line that includes the $2000 D-10 and $1000 D-500 CD transports. It should be noted that the $5595 Wadia WT-2000 CD transport is based on the P-2. Wadia buys the unit from Esoteric and fits it with Wadia's proprietary optical interface.
The P-2 is one of the most beautiful pieces of audio equipment I've seen, both aesthetically and in terms of build quality. It is solid, luxurious, and finely appointed. The front and top are anodized a dark champagne color, while the side panels are finished in 3M's Nextel, an unusual textured material. All exterior metal chassis parts (front and top) are made from very thick (18mm) and beautifully machined shaved aluminum. The metalwork is gorgeous and lavish, contributing to the P-2's overall elegance.
Rather than clutter the P-2's front-panel appearance, most of the transport functions are provided on the remote control. The only controls provided on the front panel are power on/off, drawer open/close, track skip, play, and pause. The panel's centerpiece is a very thin gold-plated drawer that recedes into the unit. The bulk of the drawer itself is Nextel: the gold-plated surface is on the outside edge visible when the drawer is closed. Below the drawer, an LED display panel provides the user with a variety of information, including track and index number, total or remaining time, and programmed play status.
Footnote 1: See "CD: Jitter, Errors, and Magic," Vol.13 No.5. The article also contains a description of how data are recovered from a CD, an understanding of which is helpful in the following discussion of the P-2.
Footnote 2: See John Atkinson's Jitter, Bits, & Sound Quality in this issue. His experiments in introducing jitter by computer simulation reveal a remarkably analog-like variability to the reproduced signal.
Footnote 3: The HF signal is the raw signal reflected from the CD and picked up by the photodetector. It is comprised of nine discrete-frequency sinewaves (196kHz to 720kHz) that correspond to the nine pit or land lengths encoded on the CD. Although the HF signal looks very analog, digital data are encoded in the zero crossing transitions.
Footnote 4: Designers with whom I've had discussions include Kevin Burke and Steve Taylor (Madrigal), Edmund Meitner and Gregory Soo (Museatex), Mike Moffat (Theta Digital), Don Moses (Wadia Digital), and Bob Stuart (Meridian).