Audio Database


Lo-D DAD-800
159,000yen(1983 release)

The compact disk player of No. 2 by which high-quality sound-ization was attained by the comprehensive technical capabilities of Hitachi Lo-D.

Three spot schemes laser pickup servo is adopted.
In this servo, two sublaser spots for a tracking error detection shifted a little to right and left other than the main laser spot which reads a signal are arranged. When tracking is being carried out correctly, the reflected light output of two sublaser spots is the same, but if it shifts even when it is small, a difference will appear in the quantity of the reflected light from the pit gathered at the sublaser spots 1 and 2, and an output will become imbalanced. This detects a tracking error quickly.

The laser light which passed the cylindrical lens has adopted as the focal error resulting from Hure of the upper and lower sides by the curvature of a disk the "longwise ellipse -> complete-round -> oblong ellipse" and the focal signal detector using the property of changing.
According to the form of the laser light included in a detector, if it is a complete round and is an exact Focus and an ellipse, it is judged as a focal error, and the error signal is outputted quickly.

The objective lens two-dimensional drive actuator original with a roadeo to which an objective lens is moved quickly is carried to a tracking error-correction signal and a focal error-correction signal.
It is an actuator similar to the voice coil of the loudspeaker, and the tracking Focus with an exact submicron precision is realized by carrying out the high-speed migration of the lens to a correction fraction at the 2-way of the upper and lower sides and right and left.

The Lo-D has adopted LSI and IC which carried out the exclusive design as all the circuitries, such as a data strobe circuitry which distinguishes a digital signal, and a digital disposal circuit which carries out the detection correction of the error and rearranges a signal as a format.

The brushless, the coreless, and the uni-torque motor of a slotless are carried in the disk motor.

The audio peculiar part, a quality pure Focus capacitor, the 11th low pass filter which selected every article carefully are adopted as an analog circuit.

An operation of random-memory song selection, direct song selection, and one-touch song selection, an index search, a manual search, a song selection head-search pause, etc. is possible.
Moreover, the repeat function which can choose all songs / song selection / 1 music / zone is carried.

An output sound volume can be adjusted.

There was a wired remote control unit as an option.

Wired Laser Parts, Digital-disposal-circuit

Rating of a mode
Form Compact disk player
<Audio part>
The number of channels Two channels
Frequency characteristic 5Hz-20kHz±0.5dB
Dynamic range 95dB
SN ratio 95dB
THD 0.003%(1kHz)
Separation 94dB(1kHz)
Wow and flutter Below a limit of measurement (±0.001%W.Peak)
Performance time 60 minute / single sided (possible for a maximum of 75 minutes)
Diameter 120mm
<Signal format>
Sampling frequency 44.1kHz
The number of quatizations A 16-bit linear / channel
Transmit bit rate 4.3218Mb/a second
Scheme Objective lens drive system optical pickup
Objective lens drive system Two-dimensional parallel drive
Light source Semiconductor laser
Wavelength 790nm
Output voltage 2.5Vrms
Supply voltage AC100V, 50Hz/60Hz
Power consumption 23W
Dimensions Width 435x height 110x depth of 264mm
Weight 5.9kg
Option Wired remote control unit returns-to-biases-800 (6,000yen)