Teac VRDS-25x
Beschrijving / Description
A CD player that is an improved model of VRDS-25 that uses the VRDS mechanism.
VRDS (Vibration-Free Rigid Disc-Clamping System) is adopted for the turntable mechanism. The disc is clamped on a turntable having the same diameter as the disc, eliminating the natural vibration of the disc itself and unnecessary vibration of the mechanism system.
By giving a gentle slope to the crimping surface of the disk, warping and distortion of the disk are corrected. By the pickup which is finely adjusted to the same angle as the turntable, pit reading at the center of the pickup optical axis is always realized, and unnecessary servo current is minimized.
These features reduce disk read errors and prevent timing errors (jitter) in the clock circuit.
In addition, high-precision aluminum die-cast is used for the turntable, and it is rigidly supported by a bridge with thick reinforcement rib structure. The mechanical base and bridge have features such as low thermal expansion coefficient and resistance to temperature change. They are made of special polymer material with about twice the specific gravity of ABS resin. It not only has excellent electrical and mechanical properties, but also contributes to high dimensional accuracy.
The motor uses a brushless Hall motor that boasts high torque, and achieves rotational stability and high input resistance.
For digital transmission, the DSRLL (Digital Servo-Ratio-Locked Loop) circuit used in the Esotheric D-3 is used. This circuit successfully reduces jitters in the audible band above 3 Hz by 1/100 (40 dB).
The chassis structure has been revised to ensure that there is no vibration and no resonance.
The top plate has a 3-piece structure made of thick steel board. Especially, the left and right 2-pieces are integrated with L-shaped side panels, making it strong against twisting and deflection.
In addition, thick solid aluminum blocks in the form of bridges that directly connect the front panel and rear panel are installed at the top and bottom of the unit. In addition to strengthening the chassis, the inside is covered with non-magnetic aluminum as a three box structure, preventing interference with the D/A section, mechanical / servo section and power supply section.
In addition, the bottom chassis is 2 mm thick, and a pin-point foot made of sintered alloy is used for the insulator.
It uses a distortion and shaper ZDII, and D/A conversion errors are averaged by dither, realizing an ideal conversion step of 21 bits (2,097,152 steps).
The VRDS-25x operates in a double-differential mode and achieves a significant improvement in SN by operating on a 50 MHz high-bandwidth amplifier.
To further improve the ZDII averaging principle, we have adopted a 1 / 16 shift (digital offset) small-signal oriented DAC that eliminates the MSB errors that normally occur near 0 V.
By shifting the 0 v operating point of the DAC by one sixteenth of the scale, the 0 cross distortion that occurs when the input code passes through 0 v is reduced to about one eighth of the conventional one. This greatly improves the r-ty in the signal region (-18dB or less) where music signals are concentrated.
The digital filter also includes a 25-bit 8 x oversampling digital filter.
It is equipped with a digital servo that adjusts the servo amount for each disk. It controls the servo amount of focus offset, tracking balance, focus gain, and tracking gain that are optimal for each disk. The stable and efficient servo current reduces jitter.
A digital input is mounted for digital signals, and extremely pure D/A conversion is realized by passing through a DSRLL circuit.
The pattern design of the double-sided PCB has a wide ground plane, and the center bus bar is used to make the PCB resistant to external noise and high transmission efficiency.
It also uses carefully selected capacitors, diodes and transformers, and high-quality elements such as brass shavings and gold-plated RCA plugs.
Specificaties / Specifications
Type CD Player
Number of audio channelsKaraoke machines 2 Channel
Frequency characteristic RCA : 1 Hz to 20 kHz +/- 0.3 dB
XLR : 20 Hz to 20 kHz +/- 0.3 dB
Signal-to-noise ratio 110 dB or more (EIAJ)
Dynamic range 99 dB or More (EIAJ)
Total harmonic distortion factor 0.0015%(EIAJ)
Wow and flutter Measurement limit value or less (crystal oscillation accuracy)
Channel separation 108 dB or more (EIAJ)
Analog output RCA:2.2Vrms
XLR : 2.2Vrms/600 termination
Digital Output (ON/OFF Possible) Coaxial (RCA) : 0.5Vp-p/75
Optical (TOS) : -15 to -21dBm
D/A converter 1/16 shift 20-bit 4 dac
Digital filter 25-bit 8 x oversampling digital filter
Analog filter Third order Butterworth filter
Pwer 100 VAC, 50Hz/60Hz
Power consumption 18W
Outer Diameter Dimension Width 442x Height 145 (When Using Foot : Approx. 153 mm) x Depth 344 mm
Weight 16.5kg