For those who insist on the best possible playback chain for their CDs or those discriminating listeners who wish to continue enjoying their CD collections well into the 21st century, the Nº31.5 Reference CD Transport offers unparalled performance and real value.
The characteristics of an outstanding CD transport are simple to define: it must recover the correct data from the disc, and deliver it to the digital processor without any timing errors (sometimes called “jitter”). As simple as this sounds, achieving it in reality has been extremely difficult—as evidenced by the significant sonic differences between various CD transports.
Conventional CD transport design depends on the quality of the oscillator used to control the rate at which the disc itself spins. This oscillator exists in an extremely “noisy” electrical environment close to the motor that spins the disc. The electrical noise introduces timing errors in the delivery of the digital signal that have come to be known as “jitter.” Subsequent handling of the digital audio signal in traditional transport designs cannot improve upon this “jittery” signal, lacking a better reference. To the contrary, the various stages of signal processing between the laser pickup and the final output can only contribute additional jitter of their own.
The Mark Levinson Nº31.5 leaps beyond conventional digital audio technology by employing a proprietary, closed-loop jitter-reduction system in conjunction with a double speed CD-ROM drive. Using a custom-made, mechanically and electrically isolated crystal oscillator as a reference, the digital signal is reclocked immediately before the output, eliminating transport-related jitter from the digital audio signal. This same five part-per-million crystal oscillator controls the all-digital servo used to control the rate at which the disc spins.
In effect, the design of the Nº31.5 turns the accepted status quo on its head. By placing the all-important reference clock in the final stage of the transport’s output section, and slaving the mechanical subassemblies to it rather than the other way around, the signal presented to the outputs of the Nº31.5 is uncontaminated by electrically- or mechanically-induced jitter. The sonic advantages of this design are immediately apparent in the clarity, warmth and stunning dynamic contrasts exhibited by the Nº31.5