Cd Head Unit - Alpine F#1 Status CDA 7990R User Manual

CD Head Unit

Carefully selected and fine-tuned high-precision parts to
attain "best accuracy" for distortion-less reproduction of
minute signals.
A new high precision "DP-ST", ensures precise retrieval of digital information and
high vibration resistance.
The DP-ST achieves six times greater precision than conventional CD products by incorporating
accurate skew optimization along the X, Y, and Z axes.
The DP-ST keeps the laser much more perpendicular to the CD compared to Alpine's already high
quality transports. This reduces data reading errors. Since the following circuits correct fewer errors,
they "strain" less, improving the "easiness" of the music DP/ST has the best-in-industry data readout
accuracy, which can be provided to only the flagship model.
Hand picked K-Grade "Sign-Magnitude" 24-bit DACs from Burr-Brown offer the highest
precision available.
Many types of Digital-to-Analog Converters (DACs) exist: the original multi-bit, 1-bit, bitstream,
MASH, delta-sigma, etc. But the Sign-Magnitude DAC still remains unequaled. The Sign-Magnitude
Multi-bit DAC, uses precision laser-trimmed ladder resistors to precisely decode each bit, while a
unique architecture sidesteps zero-cross distortion problems. Since even such precision manufactured
products have slight variance, each "K" grade DAC is hand picked and carefully selected for use. K-
grade products achieve a three-times lower distortion rating and higher S/N ratio compared to the
already awesome basic Sign-Magnitude. It is the highest grade DAC that can be produced at the
present time, with incredible capability to eliminate low-level noise, thus reproducing a sensitive
expression of the music performance.
Promising the highest precision: Burr-Brown matching 24-bit digital filter.
The PXA-H900 utilizes a very high grade 24-bit, 8 times oversampling digital filter. This companion
unit to the Burr-Brown "Sign-Magnitude" 24-bit DAC promises the highest accuracy and precision
available today. In fact, by cutting noise outside the audible range, high-precision reproduction with
ultra-wide dynamic range is possible. This creates a rich abundance of musical information and
harmonics.
By eliminating high-frequency noise, quietude and depth are reproduced: "GIC-type
low-pass filter"
In all CD systems, a lowpass filter keeps digital noise out of the music. Instead of a typical series
filter, Alpine has employed a GIC (Generalized Impedance Converter) filter. This type of filter
essentially short-circuits spurious noise signals while letting the music passes directly to the next
stage. Removing the series filter keeps the music purer. And, by using the special GIC filter, high-
frequency noise that cannot usually be removed by 8 times oversampling is eliminated. This high
precision low-pass filter extracts only the true musical information.
Sound quality not possible with typical "Balance" and "Fader" circuits has been
achieved: "Independent Precision Attenuators"
Analog volume control has been said to be preferable for sound. The common analog implementation
requires three circuits in series to achieve volume, balance and fader functions. The sound passes
through each of the three stages, and each stage inevitably adds some slight distortion and noise. With
the new circuit design, each channel employs its' own high precision ladder resistor electronic
volume. Based on the users' settings, a microchip calculates what each channel's output setting should
be, and orchestrates all channels together. Loss of music information due to passing through multiple
stages does not occur.
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