SONY CDP-M54
¥ 24,800 (released in 1991)
Commentary
A mini component size CD player with a pulse 8D/A converter.
The D/A converter consists of a high-density linear converter system, a new version of the 45-bit noise-shaping digital filter (CXD 2560) and a pulse D/A converter.
The Pulse D/A converter consists of a current source and an electronic switch. It expresses music waveform by switching two values of 0 and 1 at high speed. By this, the amplitude level is always constant and changes only in the time axis direction. The PLM (Pulse Length Modulation) wave is output. By passing it through a low-pass filter, unwanted high-frequency noise outside the audio band is removed and music waveform is obtained.
To reduce quantization noise in the audible band up to 20 kHz, the pulse D/A converter is equipped with a multi-stage noise shaping operation that employs 64 times oversampling and the Sony Extended Noise Shaping method. Oversampling reduces quantization noise in the audible band by increasing the sampling frequency. Noise shaping reduces quantization noise in the audible band by feeding back the requantization error to the input side when the number of bits is reduced. These technologies ensure a high dynamic range.
The pulse D/A converter operates at 45 mega pulses per second, and it completely eliminates differential non-linear distortion, glitch, and 0 cross distortion, which were difficult with conventional methods.
The CDP-M54 uses an output-mode pulse D/A converter. The two pulse D/A converters are modulated to complement each other and differentially synthesized to cancel harmonic distortion. Moreover, the complimentary service current is doubled to increase the SN ratio.
To take advantage of the pulse D/A converter, the high-density linear converter system is equipped with a 45-bit noise-shaping digital filter in the front stage.
This circuit achieves a high dynamic range by performing a highly accurate oversampling operation and a first order noise-shaping operation on the operation result.
A direct digital sink is used to prevent degradation of sound quality due to jitter.
In this method, the master clock is formed on the same chip of the pulse D/A converter, and the jitter is removed immediately before the electronic switch, which is the final stage of the pulse D/A converter, thereby reducing sound quality degradation due to jitter.
The servo circuit uses a high-precision digital servo.
In this circuit, the signal from the optical pickup is A/D converted, filtered and controlled by digital processing, and then D/A converted again to operate the optical pickup, making it possible to adjust the servo amount according to each disc.
The high precision servo uses high sampling rate, high precision and high resolution A/D converter and D/A converter to realize ideal servocontrol and low power consumption by digitalization.
The mechanical deck is located in the center of the chassis to minimize the rotational moment applied to the chassis and improve the stability against vibration.
It has a custom edit function and eight functions : peak search, time edit, just edit, link edit, program edit, time fade, variable fade, variable fade and manual fader.
In peak search, all songs are searched at high speed, and they are repeatedly played for about 4 seconds before and after the point where the volume level is highest.
Time Edit enables efficient editing of the A-side and B-side when recording tapes.
If you want to edit to fit the length of your tape, use the TIME SET button or AMS button to set the length of the tape (you can also use the direct key to set the length in seconds). Press the Edit button. First, program from the first song for side A. When you encounter a time-over song, select the longest song that fits within the time. Then press the Edit button to edit side B.
Also, if you select and edit a half disk with the AMS button, tracks are distributed so that the A side and B side of the tape are about the same length without changing the order of the songs.
Just Edit is an evolution of Time Edit. It automatically finds and programs the combination of songs closest to the specified time.
You can set the A side and B side at the same time as in Time Edit.
Link Edit allows you to add music to the remaining tapes from Time Edit or Just Edit.
If you have programmed all songs and there is room for more songs within the editing time, the track number of the song to be entered and the LINK display will blink, and you can add a song by reselecting from the songs with the blinking track number.
Link-edit also allows you to swap disks and continue editing.
Program Edit allows you to manually edit your favorite songs in any order.
With the AMS key or direct key, you can program your favorite songs in any order while checking the accumulated time. If you turn on Auto Space at this time, you can edit each song by adding a 3-second blank to the playing time. When you press the pause button, you can program the A side and then the B side together.
Time Fade allows you to fade out at a specified time, which can be set with the TIME SET button or the AMS button.
You can set the fade-in / fade-out time for the variable fade from 2 seconds to 10 seconds in units of 1 second.
The manual fader allows you to fade in and fade out at the desired location.
It is equipped with a delete play function so that you can play continuously with only the music you want to listen to. If you delete unnecessary music in shuffle mode and then switch to continue mode to play, you can skip that music and play the next one.
In addition, it is equipped with a 99 track delete shuffle function so that you can leave only your favorite music and play it randomly.
It is equipped with Music Scan and plays only the beginning part of the song one after another.
You can choose from three performances : 10 seconds, 20 seconds and 30 seconds. Both of them come with a 2-second fade-out. You can also use the Clear button to delete songs you don't want to listen to while scanning.
Equipped with an auto-queue function, you can search automatically to the point where the sound starts in a pause state.
The AutoSpace feature allows for approximately three seconds of silence between songs, and reduces to a minimum of three seconds for discs with more than three seconds between songs.
It is equipped with functions such as program performance of up to 24 songs, 6-mode repeat of 1 song / all songs / program / delete play / shuffle / delete shuffle, AMS and music search.
The display section has a 20-track music calendar.
Equipped with two line-out terminals, fixed and variable.
It is also equipped with a headphone jack with a lineout linked volume.
Wireless remote control is included.
Model Rating
| Type | CD Player |
| Frequency characteristic | 2 Hz to 20 kHz ± 0.5 dB |
| Total harmonic distortion factor | 0.003% or less (EIAJ) |
| Signal-to-noise ratio | 105 dB or more (EIAJ) |
| Dynamic range | 98 dB or More (EIAJ) |
| Wow and flutter | Below the measurement limit (± 0.001% W. peak) (EIAJ) |
| Output level | 2Vrms(Fixed) |
| Headphone output level | 10 mW (50k Ω) |
| Power consumption | 10W |
| External dimensions | Width 355x Height 95x Depth 325 mm |
| Weight | 3.2kg |
| Attachment | Wireless Remote Control RM-D597 |