Audio Database

The

NEC CD-810
89,800yen(around the 1987 time)

Description
 
The compact disk player which carries a 16-bit digital filter and a twin digital analog converter.

In order to eliminate a digital noise from an analog circuit, the optical-transmission scheme is adopted.
By this scheme, the signal from a digital circuit is changed into light, and it is transmitting to the analog circuit,The separation and the independency of a digital circuit and an analog circuit are realized including a L/R serial data by using the optical transmission by a photocoupler for five lines, such as an emphasis signal, a latch pulse signal, and a clock signal.

The 16-bit digital filter is adopted as a digital filter, and the burden of an analog filter is eased.

The twin digital analog converter which equipped L/R independently is carried in the D-A-conversion part, and the phase difference which was not avoided is banished by the single digital-analog-converter scheme.

Noise mixing to an analog system is prevented by adopting as a power-source part the independent 2 power-source scheme which separated the digital system and the analog system from the stage of the power transformer completely.
Moreover, a shunt-regulator power source is adopted as an analog circuit, and the stability is raised.

The fine oscillation from an internal-rotation system is absorbed because a chassis reduces a magnetic distortion by giving a copper plating and also adopts the steel plate of 2.0mm thickness as a sole plate. Moreover, the sintered alloy foot (50phi15mm) which was excellent in the vibration-proof dynamic behavior with high rigidity is stuck to a floor surface, and a long oscillation and extraneous vibration of a periodicity are supported.

The software of an opposite phase can be reversed with an absolute phase circuit changing switch.

A magnetic distortion is eliminated by surrounding an analog part with a steel plate.

The large-sized insulator is adopted as a mounting of a power transformer.

The 70-micrometer thickness OFC Copper-foil printed circuit board is adopted as the printed circuit board.

It can change into a three-position supporting by changing the mounting location of a foot.

The power source only for headphone amplifier is carried.

The index search / time search function is carried.

A 24 music random program memory functionality and three kinds of repeat functions are carried.

Wireless remote control with a ten key is attached.

Internal Attached
16-bit

Rating of a mode
Form Compact disk player
Pickup scheme GaAlAs double heterodyne semiconductor laser
Rotational frequency About 500-200rpm (CLV)
Performance velocity 1.2 m/s - 1.4 m/s (regularity)
Error-correcting system cross-interleaved-Reed-Solomon-code double error-correcting system
The number of channels Two channels
Composite-izing 16-bit linear line
Frequency characteristic 5Hz-20kHz±0.5dB
THD 0.005% or less
Dynamic range 95dB or more
SN ratio 100dB or more
Channel separation 92dB or more (1kHz)
Wow and flutter Below a limit-of-measurement value (quartz-crystal oscillation precision)
Output voltage 2.0Vrms
Supply voltage AC100V, 50Hz/60Hz
Power consumption 23W
Dimensions The width 430x height 101.5x depth of 335mm
Weight 8.8kg
Adjunct Wireless remote control AR-810