Even if
the Rossini CD Player REV2.0 has the same look of the previous revision it is
completely different inside.
With the REV2.0 we have created a unit where vacuum tube
technologies and the best digital technologies have been perfectly mixed
together. The circuits we have used are the result of a long period of
research, especially for the original vacuum tube output stage that is the
strong point of this CD player. The results we have had have been even higher
than what we were originally aiming for. In particular the listening sessions
showed that the Rossini CD Player REV2.0 has a “different” and “original” sound compared to other CD Players.
The Rossini CD Player REV2.0 represents a new starting point because
it has demonstrated that the union of vacuum tube and the most modern
technology has a promising future. We must go down new streets, try new
circuital solutions, and revise the old configurations without falling into the
mistake of “too much” a “microelectronic”
approach.
Digital Input
The S/PDIF signal is taken from the Cd Mechanism. We have used a CD
ROM mechanism specifically developed for the audio application (We even
contributed to the design for the firmware test part and for the mechanical
stability tests). In fact the maximum speed has been reduced compared to the
standard CD ROM mechanisms, and the reading procedure has been made more “Jitterless” and sturdy. To avoid any interference from ground returns we have
isolated the S/PDIF CD mechanism output from the main board by a transformer.
The SPDIF signal is then send to the DA conversion PCB.
Digital Analog Conversion Section
The circuits performing the digital to analog conversion are placed
on a board physically separated from the main board. That’s to avoid any interference on the analog signals due to the return
currents of the digital parts of the DAC and transceiver. On the board there
are: the transceiver, the DAC and all their frameworks including their power
supply voltage regulators and capacitors. The voltage for the “DAC board” is obtained by a dedicated secondary of the transformer and a
dedicated voltage regulator. The regulated voltage is then filtered by a RC
filter. Then that voltage is used to produce the voltages for the transceiver
and DAC by two voltage regulators. The components on the “DAC board “ are
predominantly SMD reducing the length of traces carrying high frequency signals
to avoid irradiation effects. From the “conversion board” the
voltage DAC output is sent to the main board.
Output Stage
The
output stage is an original circuit designed by the Audio Analogue R&D
office to emphisize the sound propertyes of the vacuum tube and to take vantage
of the solid state technology. It is an inedited DC coupled low feedback three
stage structure where the vacuum tube is the first one. The amount of feedback
has been choosen not only on the base of measurements but on the base of
listening tests too. What we have tried to do is a balance of the vacuum tube
“coloring” and DAC “cleanliness”. The output stage’s gain is such that we have
1.9Vrms output for a 0dBV track.
Anodic Power supply
The output stage used is not based on a differential input so the
noise on the anodic supply is not reduced by the circuit. That’s why we have worked on the anodic power
supply to make it as clean as possible. The voltage for the anodic power supply
is obtained by a high voltage dedicated secondary and then regulated with a
discrete components voltage regulator. The regulator output is then filtered by
a RC filter with a very low time constant (less then 1.24).
SPECIFICATIONS
D/A Section
Transceiver: AK4114
192KHz/24bit - Asahi Kasei
DAC: AK4395
192KHz/24bit - Asahi Kasei
Total
Harmonic Distortion (at 1kHz 0dBFs): less than 0,001 % (Band limits 0Hz-22KHz )
Total
Harmonic Distortion (at 1KHz, -10 dBFs): less than 0,006 %
(Band limits 0Hz-22KHz )
Noise
Level: -120 dBV (Band limits
0Hz-22KHz )
Output
Level: 2,00 (Maximum RMS
voltage output value )
Digital
Output: Coaxial
Vacuum Tube Output
Stage
Unbalanced Output
CD
Mechanism: TEAC CD-5010A
Dimensions
(H x W x D): 78 x
444 x 371 mm (3,1" x 17,5" x 14,6")
Weight: 10,6 kg (23,4 lbs)
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