Audio Database

Image of the PD-T05
Commentary

This is the first generation CD player using the turntable system.

It uses a CD turntable system developed from a disk stabilizer.
By installing the pickup and spindle motor on the upper part of the disc, it is possible to support the disc from the bottom to the entire surface of the turntable just like an analog player.
As a result, the moment of inertia of the turntable has been improved to about three times that of the conventional one, and it is resistant to external vibration, sound pressure, warped disks, etc., so that unnecessary vibration of the disk can be suppressed.

The D/A converter is equipped with an 8 fs digital filter and a left-right independent bit stream D/A converter.
In principle, this D/A converter is free from non-linear distortion or 0 cross distortion caused by resistor error or operation timing difference like the multi-bit system. Moreover, the effect of the noise shaper is kept low by over-sampling as high as 192 fs based on the third order noise shaper.
In the 1-bit system, all operations are controlled by the system clock, and jitter in the system clock affects performance. To avoid this effect, the system clock is operated at the same low system clock (16.93 MHz) as the conventional multi-bit system.
We also pay attention to the application, and provide vibration and magnetic resistance processing such as an independent oscillation circuit.

In order to transmit music signals pure, direct construction is adopted. By laying out main circuits simply and straight along the signal flow, the shortest signal path is realized.
In addition to the center tray design with the pick-up mechanism in the center, the digital / servo and audio circuit boards are separated to prevent interference in each circuit. The analog circuit board is also connected from the input terminal to the output terminal by the shortest distance, making it symmetrical.
This eliminates interference between circuits and noise caused by the routing of wiring materials.

The pickup uses a clean laser pickup developed in-house, reducing power loss in the optical system by reducing the number of optical components such as collimator lenses, and reducing aberrations in the optical path, making it possible to pick up signals with less distortion.
In addition, an engineering plastic body is used for the body, and by dividing the pickup body into approximately 1000 elements and performing strength analysis, a high-precision and precise shape is realized.
In addition, the photodetector has a built-in I/V conversion head amplifier that amplifies the signal to the order of approximately 200 mV, enabling transmission that is resistant to disturbance noise.

The audio circuit uses a class-A FET buffer amplifier to reduce the output impedance and the influence of the load of the connected amplifier.
In addition, Class-A operation reduces fluctuations in power consumption during operation and realizes stable waveform transmission.

A high-precision four section photodetector generates a phase difference between the leading signal and the trailing Yukinobu signal when it receives laser light. To solve this problem, we have adopted an Accu-Focus system. By delaying the leading signal with a delay circuit and matching it with the trailing signal, we can obtain an RF-signal with less reading error.

The spindle motor is equipped with a brushless Hall motor with a starting torque of 65g ・ cm. In addition, combined with a thick φ 4.5 mm shaft, it demonstrates stable rotational performance that is resistant to load fluctuations.
In addition, the pickup drive employs a silent linear motor servo mechanism that enables quiet and smooth operation, enabling quick access.

Lamisert mechanical base is adopted to protect the optical mechanism from external vibration.
This is made by molding two sheets of steel plate with special resin, and copper plating is applied to improve vibration damping characteristics and suppress the occurrence of magnetic strain.
This mechanical base is mounted on a mechanical chassis via a coaxial suspension made of special rubber and springs, and the turntable base is also mounted via a coaxial suspension. Each of these mounts has a flow and structure to prevent external vibration from the chassis.

A newly developed multi-layered honeycomb chassis has been adopted.
It is based on a honeycomb chassis made of BMC (Bulk Molding Compound) with high internal loss and high rigidity. It is layered with steel plate and cushion material with excellent electromagnetic shielding. It reduces unnecessary vibration by excellent vibration control effect and reduces the reflection of sound from the floor.
The fifth insulator is installed in the center of the chassis to provide vibration resistance and weight balance, and to support the center mechanism.

The power supply is equipped with twin power transformers for digital / servo circuits and analog circuits.
In addition, a bifilar winding is used in the transformer for the audio circuit to increase the balance of output impedance and inductance so that the power supply on the + side and the power supply on the - side can be supplied under the same conditions, improving transparency and driving feeling in low frequency range.
The power supply circuit employs a 4-part 11-regulator, which independently rectifies four parts of servo / digital, servo drive and audio + and - to eliminate mutual interference.

It is equipped with a clean microcomputer that operates only when the operation key is pressed, and it cancels the scanning noise.

Equipped with a digital / analog logout selection switch.

A display off switch is installed to prevent scanning noise when the display is turned on.

Model Rating
Type CD Player
Pick-up Three beam semiconductor laser system
Frequency characteristic 2 Hz to 20 kHz
Signal-to-noise ratio (EIAJ) 115 dB or more
Dynamic Range (EIAJ) 99 dB or more
Channel Separation (EIAJ) 110 dB or more
Wow & flutter (EIAJ) Measurement limit (± 0.001% W. PEAK) or less
Harmonic distortion factor (EIAJ) Not more than 0.0017%
Output voltage 2.0Vrms
Number of channels 2 channels (stereo)
Digital output Coaxial Output : 0.5Vp-p/75 Ω
Optical output : -15dBm ~ -20dBm (wavelength 660 nm)
Pwer 100 VAC, 50Hz/60Hz
Power consumption 20W
External dimensions Width 420x Height 130x Depth 330 mm
Weight 10.0kg
Attachment Remote control