Esoteric P-2 CD transport Page 2
Three small recessed knobs on the P-2's right side panel allow the user to adjust the front-panel display brightness and control the drawer's open and close speed.
The full-featured remote control supplied with the P-2 also controls the matching D-2 digital processor. Like the P-2's side panels, it is finished primarily in Nextel, with a champagne-colored top. The remote control's functions include open/close, track skip, index skip, search, play, stop, pause, display on/off, repeat, A-B, time search, time mode (elapsed or remaining), check (programmed playback contents), delete (programmed memory contents), direct track-access buttons, and track programming controls. When programming random play, the total programmed playback time is displayed, handy for making tapes. Other convenience features include time search, allowing the user to start the transport at any time specified within a track via the numeric keypad. The autospacing function creates a four-second pause between tracks. The P-2 is clearly a full-function machine.
Inside, the P-2's build quality mirrors the exterior's extraordinary construction. When looking at the P-2's mechanism and electronics, one sees the precision and craftsmanship of a fine Swiss watch.
The heart of the P-2 is the drive mechanism, which is radically different from conventional transports and is proprietary to Esoteric. It is called VRDS, or Vibration-Free Rigid Disc-Clamping System. Rather than holding the disc at the center hole, the P-2 firmly clamps the CD over its entire surface area to a zinc turntable slightly larger than the CD. This reportedly reduces surface vibrations, improving the precision with which the data are read. In addition, the turntable is slightly concave, correcting any warping or eccentricity of the disc. The laser is adjusted to the disc's slightly concave surface so the beam always stays perpendicular to the disc surface.
Besides reducing vibration, the turntable/disc's stability as rendered by this mechanism is said to reduce servo current demands. A slightly warped disc on a conventional transport results in the reflection of the laser beam at a deflected angle, greatly increasing radial servo activity. Indeed, disc flatness is often specified by the maximum radial tracking voltage allowable (typically 250mV RMS after filtering and processing). The Esoteric P-2 mechanism also eliminates eccentricity, an out-of-round condition analogous to a misplaced center hole in an LP. Just as the tonearm must swing back and forth to follow the eccentric LP groove, the CD mechanism's radial tracking servo must drive the laser sled back and forth to follow the eccentric track of pits. Eccentricity in a CD is introduced by a misplaced center hole, with the maximum allowable deviation 0.4mm.
One potential source of problems in many CD players is the fact that the focus and tracking servo signals, with their large fluctuating currents, are carried in a thin ribbon cable along with the HF signal, possibly corrupting it. In fact, I believe that many mechanical CD tweaks like rings improve the sound by reducing servo current demands, especially in players with poor isolation or marginal power supplies. It should be noted that the P-2's clamping mechanism precludes using additional damper discs, rings, or any other device that changes the CD's size or shape. Presumably, the P-2's mechanism obviates the need for additional stabilizing tweaks.
The zinc turntable is designed to have a low resonant frequency and high vibration-damping characteristics. Because the turntable is so heavy, a special motor was developed employing samarium-cobalt magnets instead of standard ferrite magnets. This motor is mounted on a diecast aluminum bridge assembly that straddles the turntable and drawer sled. Because of space constraints, rotational drive motors are typically mounted beneath the turntable next to the laser head rather than above the rotating mechanism. The drive system's mechanical rigidity is thus compromised in conventional designs. By positioning the motor and mount assembly above the turntable and away from the laser sled, Esoteric engineers were given the freedom to make the drive system as rigid and as large as was felt necessary. Finally, the entire motor/support system is mounted to a massive 1kg (2.2 lbs) diecast zinc base.
The attention paid to making the P-2 mechanically rigid is extraordinary. Even the chassis and front panel were designed to increase the P-2's vibration resistance. What effect this will have on the recovered HF signal and, more important, on musical reproduction, are interesting questions. There is no doubt, however, that the HF signal recovered from a disc on the P-2 has substantially lower jitter than when recovered on a standard Philips CDM1 Mk.2. During my investigation of CD tweaks on error rates and jitter mentioned earlier, I used a Kenwood jitter analyzer to measure the possible effects of different CD treatments. The Kenwood analyzer measures the period of I3 (the shortest pit or land length on a disc, which should ideally be 694ns) and displays the distribution (typically Gaussian) around this value. Although the study didn't include transports, I measured the P-2's jitter out of curiosity just before I had to return the analyzer. The difference between the P-2 and a standard transport was startling.
I had set the analyzer to display the percentage of I3 values that fell outside a >50ns window around the ideal value of 694ns. With the Philips transport in a Magnavox player, 78% of the recovered I3 periods fell outside this window. With the P-2 (and the same disc), only 28% of the I3 periods deviated more than <50ns from the ideal value. Note that this jitter is in the raw signal recovered from the disc before being reclocked out of the FIFO (First In, First Out) buffer and will be very great due to rotational speed variations in both the CD mastering machine and the player drive mechanism. This large amount of jitter (tens of nanoseconds) in the raw HF signal is contrasted with the relatively small amounts of jitter (hundreds of picoseconds) in the clock signal at the converter that still creates sidebands and noise as described in JA's Meridian 208 review in this issue (footnote 5).
The P-2's power supply is on an upside-down pcb about 7" square mounted at the top rear of the unit. It is enormous and elaborate for a CD transport. The board is populated by large (4700µF and 6800µF) electrolytic caps, many smaller electrolytics, two full-wave bridge rectifiers, high-power transistors, and five three-pin (TO-220) voltage regulators. This power supply is extraordinary for a CD transport. It is difficult to imagine any servo-system interaction through the power supply in the P-2.
Lying on the chassis bottom beneath the transport mechanism, a large pcb holds an extensive array of chips and a few discrete components. I've never seen so much circuitry associated with a CD transport. This board provides the servo systems, decoding, error correction, formatting, and control/display functions.
To sum up, the Esoteric P-2 is innovative in design and elaborate and lavish in execution. The unique disc-clamping mechanism, tank-like construction, and elaborate power supply confirm that the P-2 is a no-holds-barred attempt at a state-of-the-art transport. In addition, the P-2's beautiful styling and extraordinary fit and finish place it among the most luxurious and elegant of audio components.
But is the P-2 just a $4000 piece of audio jewelry, or does it significantly improve the musical experience from CD playback over less ambitious designs?
I began by comparing the P-2's digital output with the Rotel RCD-855's, decoded by the Stax DAC-X1t digital converter. Identical lengths of Aural Symphonics Digital Transmission Line cable connected the P-2 and Rotel to the Stax. The multiple-input Stax allows direct comparison of two digital sources by selecting a different input. In this situation, all variables are removed (playback level, impedance matching, polarity inversion, cables, etc.) except the transports under audition. Since I had become accustomed to the P-2 from six months of exclusive listening, switching transports for the first time for this review threw into sharp relief the differences between a state-of-the-art transport and a typical inexpensive mechanism found in many CD players. (Note that all references to the Rotel RCD-855 in this review are to it used as a transport only.)
Footnote 5: I found that the amount of jitter intrinsic to the disc varied much more from disc to disc than between transports. This jitter is introduced by speed instability in the CD mastering machine's rotational drive, which can be quite large. If the P-2's superior sonics are at least partially the result of reduced jitter in the HF signal, then it follows that different CD mastering machines will have varying sonic characteristics. Bits is bits?