Audio Analogue Rossini VT CD Rev 2.0

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)