HP N31.5 - Manual (Page 10)

10
Special Design Features
Congratulations on your purchase of the Nº31.5 Reference CD Transport. The
Madrigal design team is confident you will enjoy the outstanding performance of
the Nº31.5 for many years. In case you are interested in technical details, what
follows is a brief outline of some of the key technologies in your new transport.
A New Generation 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 with-
out any timing errors (sometimes called “jitter”). As simple as this sounds, achiev-
ing 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 ex-
tremely “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 sig-
nal in traditional transport designs cannot improve upon this “jittery” signal, lack-
ing a better reference. To the contrary, the various stages of signal processing be-
tween 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 out-
put 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.
Digital Servo Control The laser mechanism used in the Nº31.5 uses all an digital servo control. Critical
functions such as focus and tracking are handled completely in the digital do-
main, with mathematical precision. Whereas conventional, analog servos may re-
quire periodic realignment for optimum performance (to compensate for the ag-
ing of various analog components), a digital servo remains stable over time,
never needing readjustment under normal conditions.
Output Versatility The Nº31.5 supports a wide variety of digital output configurations to ensure op-
timal performance with a wide range of digital audio processors. A new comple-
mentary driver for the balanced AES/EBU electrical output delivers outstanding
performance to the high quality XLR connector. Single-ended S/PDIF electrical
output is provided via an RCA connector, and the ST optical output uses a high-