Audio Database

The

Pioneer PD-T07
150,000yen(1990 release)

Description
 
The turntable scheme compact disk player which carries legato linking conversion.

In compact disk, in order to reproduce the sound of 20kHz or more cut and to play a more natural music, legato linking conversion is carried.
In this circuitry, in order to improve pulse-response-characteristics nature more, between the datas of the music signal in every 22.7microsec currently recorded on compact disk is connected with the smooth function curve suitable for reappearance of the frequency component of a musical instrument etc. Thereby, wave-like reappearance near an original music signal with few unnecessary ringings (wave-like disorder) is enabled.
Moreover, by presuming the original signal before being recorded based on the signal currently recorded on such a compact disk, it became possible to the reappearance with a sound of 20kHz or more according to a 1/f damping characteristics, and a play sound very natural also on Hearing impression and smooth has been obtained.

In order to suppress an unnecessary oscillation of a disk, compact-disk turntable scheme is adopted as a mechanism.
By moving a pickup and a spindle motor to a upper portion from a disk lower, and supporting a disk all over a turntable, it is strong also on an extraneous vibration, the influence of sound pressure, and a disk with curvature, and the unnecessary oscillation of a disk is reduced.
Moreover, since it is strong also to a load variation, the stable rotation performance has been realized.

The high speed pulse flow digital analog converter of an original development is carried in the D-A-conversion part.
In this digital analog converter, by operating a noise shaper on 384fs and a very high oversampling frequency, a fine sampling is attained and the noise floor by re-quatization is reduced greatly. Furthermore, since a noise shaper can also be used by the sub- and a low degree, the influence of the tone qualities on an out-of-band noise etc. is also suppressed.
Moreover, the influence of a Jitter is suppressed by operating a master clock with a clock frequency as low as 16.93MHz.

Main circuitries have been arranged in the simple & straight along with the fluence of a signal, and the direct construction which attained shortest-ization of the signal path is adopted. The center tray design which allotted the pickup mechanism in the center was begun, digital one/servo, and the audio substrate were gained separate independence, and the cross interferencee is prevented.
Furthermore, seal dead PCB (double-sided printed circuit) is adopted as an audio substrate, it received that the noise from a digital system to an audio system flew, and the outstanding shielding effect has been acquired.
Moreover, even the output-terminal was tied with the shortest distance from the input, and the break-in of a noise and the cross interferencee of a circuitry by leading about of product-line material are eliminated by having a symmetrical stream composition.

The proprietary clean laser pickup is adopted as a pickup part.
In this pickup, optical parts, such as a collimator lens, are reduced and the power loss of optical system is decreased. Furthermore, the aberration in an optical path is reduced and reading of little clean and distorted signal is made possible.
Moreover, the engineering plastic body was adopted as the body, the pickup body was divided into about 1000 member, and highly precise precision form is realized by conducting an intensity analysis.
Furthermore, I/V head amplifier is built in the photodetector and the Accu Focus system which decrease in number a reading error of a signal, and the Jitter occurrence according to a reading error or disturbance conjointly are suppressed.

The Accu Focus system which reduces a reading error of a signal is carried.
When highly precise 4 splitting photodetector receives laser light, the phase difference arises between the signal of a lead, and the signal of the back line, and RF signal is confused. In order to improve this, high-output RF signal with little reading error of a signal has been acquired by delaying the signal of a lead by a delay circuit and making it agree with the signal of the back line.

Class-A operation FET buffer amplifier is adopted as an audio circuitry, an Output load impedance is lowered and the influence of the load intensity of the amplifier connected etc. is suppressed low. Furthermore, a variation of the power consumption at the time of an operation is reduced by considering it as a Class-A operation, and the stable waveform transmission is made possible.

The brushless hall motor with the high torque of starting torque 65 g-cm is carried in the spindle motor. With the phi4.5mm very-thick shaft, conjointly, it is strong to a load variation and the stable rotation performance has been obtained.
Moreover, it is quiet, and the operation has adopted as a pickup drive whether it is a smooth silence linear motor servo eye, and has realized the smooth access to it.

According to the structure which had adopted the lamisert Mechanism-base, piled up two steel plates, and carried out molding by the special resin, a periodic-damping property is improved and the occurrence of a magnetic distortion is suppressed.
Moreover, the Mechanism-base is mounted on the mechanism chassis through the coaxial suspension which coaxial-ized special rubber and a spring, and is intercepting the unnecessary oscillation transmitted from a chassis by using a float structure.

The multilayer structure honeycomb chassis is adopted as a chassis. This is reducing the unnecessary oscillation according to the vibration suppression effect which are the steel plate excellent in the electromagnetic shielding, and the thing which piled up cushion material, and was excellent in the Takauchi part loss based on the honeycomb chassis by BMC (Bulk Molding Compound) of a high rigidity.
Furthermore, the large-sized honeycomb insulator which also suppresses a reflection of the sound from a floor low is adopted, and by in addition installing the 5th insulator in the central part of the chassis, while improving the vibration proof of a chassis, the center mechanism is supported.

The twin power transformer which made it become independent digital one/object for servo circuitries, and for analog circuits is adopted as a power-source part.
Furthermore, the push pull power source of a discrete stream composition is adopted as an audio circuitry, a by filer volume is adopted as the transformer for audios, and the tone-quality modification is aimed at.
A power circuit is 5 part 12 regulator, and + of a servo/digital one, a servo drive, a digital analog converter, and an audio and - carried out 5 part independent rectification of it, and it has prevented the cross interferencee.

The scanning noise is stopped by adopting the clean microcomputer which operates only when the operation key is pressed.
Moreover, the display-deviceoff switchpoint is carried and the scanning noise occurrence at the time of display-device lighting is prevented (backup correspondence).

Digital one / analog out circuit changing switch is carried (backup correspondence).


Rating of a mode
Form Compact disk player
Pickup 3 beam semiconductor laser scheme
Frequency characteristic 2Hz - 20kHz
SN ratio (EIAJ) 115dB or more
Dynamic range (EIAJ) 99dB or more
Channel separation (EIAJ) 110dB or more
Wow and flutter (EIAJ) Below a limit of measurement (±0.001%W.PEAK)
THD (EIAJ) 0.0017% or less
Output voltage 2.0Vrms
The number of channels Two channels (stereo)
Digital output Coaxial output: 0.5 Vp-p/75ohms
Optical power: -15dBm--20dBm (wavelength of 660nm)
Power source AC100V, 50Hz/60Hz
Power consumption 17W
Dimensions Width 440x height 130x depth of 330mm
Weight 10.0kg
Adjunct Wireless remote control