KENWOOD DP-7050
¥ 59,800 (around 1993)
Commentary
A CD player developed with the aim of high-purity D/A conversion by investing various technologies.
Equipped with an advanced high-precision master clock which is a further development of the high-precision master clock.
In a conventional master clock with an inverter circuit, the inverter circuit itself has a gain of 20 to 30 dB, and when an oscillation circuit is configured, the input terminal has a high impedance, so external noise is likely to enter and the purity of the oscillation frequency is lowered.
On the other hand, in a high precision master clock with a discrete configuration, the Modificational Clapp oscillator circuit is based on a Source Follower circuit and has a gain of less than 1. Therefore, even if external noise enters the input section, it is not amplified into the output, and the purity is 10 to 30 times higher than that of a normal oscillator circuit.
The Advanced High-Precision Master Clock on the DP 7050 has been further improved to reduce the minute noise inside the junction field effect transistor (J-FET).
The D/A converter is equipped with a bit stream 1-bit D/A converter (DAC7) with excellent differential linearity.
High signal-to-noise ratio (S/N) has been obtained by adopting a PDM method in which the 1-bit pulse density is changed according to CD data. To create this PDM waveform, a switched capacitor integrator was used to generate high-density pulses.
As a vibration countermeasure, 3 mm thick aluminum material is used for the front panel, and 1.6 mm thick steel plate is used as a box-shaped base for the chassis part, and the mechanical floor is constructed with a twin beam structure.
In addition, 1.2 mm steel plate is used for the back panel, and aluminum clamper is used to suppress the effect of sound pressure on the disk surface and to make spindle operation more stable.
The upper part of the mechanism is completely shielded by an aluminum panel, and a large φ 60 mm insulator is used.
In the rectifying circuit section, a large-capacity and large-size block Chemi-Con is mounted on the + - 2 system, the servo circuit section and the analog circuit section for exclusive use as a condenser for rectification, and interference with noise sources is suppressed by the current supply with allowance.
A high-precision differential amplifier circuit with high common-mode rejection ratio (CMRR) is used in the first stage amplifier section immediately after the D/A converter.
Equipped with an AB-CLASS pickup actuator drive circuit that suppresses sudden changes in ground potential.
It is equipped with an RF phase equivalent compensation circuit to review the AM/PM noise and prevent phase shift.
It is equipped with a power backup memory, a motor drive output volume that can be controlled by a remote control, and a disk file function that can store up to 80 sheets of data.
Model Rating
| Type | CD Player |
| Reading system | Noncontact optical readout (semiconductor laser) |
| Number of revolutions | Approximately 200 rpm ~ 500 rpm (CLV) |
| Frequency characteristic | 4 Hz to 20 kHz (EIAJ) |
| Signal-to-noise ratio | 105 dB or more (EIAJ) |
| Dynamic range | 100 dB or more (EIAJ) |
| Total harmonic distortion factor | 0.001% or less (EIAJ) |
| Channel separation | 100B or More (EIAJ) |
| Wow and flutter | Below Measurement Limit (EIAJ) |
| Output Level / Impedance | Fixed Output : 2Vrms/0.4k Ω (EIAJ) Variable Output : 0 V ~ 2 V (1.1 kHz) |
| Headphone out | 20 mW (16 Ω) |
| Optical digital output | -15dBm ~ -21dBm (emission wavelength 660 nm) |
| Power supply voltage | 100 VAC, 50Hz/60Hz |
| Power consumption (Electrical Appliance and Material Control Law) | 18W |
| External dimensions | Width 440x Height 127x Depth 318 mm |
| Weight | 6.8kg |
| Attachment | Remote control |