Audio Database
CDP-997
Commentary

A CD player with a pulse 8D/A converter and plenty of features.

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 997 employs 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. In addition, the SN ratio is increased by doubling the complimentary service current.

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.

Aluminum front panel is used for the front panel.


The Custom Edit function is equipped with ten functions : peak search, time edit, just edit, link edit, edit navi, program edit, multi-disc program, time 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.

It is equipped with edit navigation. When you edit a tape with time edit or just edit, the operation procedure is shown on the display. If you get stuck in the middle of setting up a song in each edit, the next procedure is shown in English every 5 seconds.

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.

Multidisk programs allow you to edit across multiple disks.
When you program in program mode and open the tray, the display "MULTI PGM" appears and the program automatically moves to a multi-disc program. You can program up to 6 discs (24 songs). You can also program poses in the middle of the program.

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.


Equipped with a custom file function, you can take advantage of seven functions : disk memory, custom index, program / delete bank, level file, DSP file, last-mode memory and file recall.

Disk Memo can record up to 10 characters per disk, 78 characters including alphanumeric characters, special symbols and blanks.

With a custom index, you can index the disc in your own way wherever you want in the index. You can set up to 10 points per disc and fine-tune it in steps of approximately ± 0.15 seconds.

In the Program / Delete Bank, you can record the settings of a program performance or a 99-track delete play.

The Level File feature lets you set different playback levels for different disks.
You can set the lineout / headphone volume to your desired volume by simply pressing the Level File button. When you insert the same disc, it is automatically set to the stored level.

For DSP files, select the desired mode and then press the FILE button while the DSP lamp is on to store the DSP mode.

In the last mode memory, you can store the play mode and fade time set just before removing a disc with a custom file. When the same disc is inserted, that mode is automatically recalled.

With File Recall, you can check what kind of file was stored.
This function can be function even if you don't have a disc installed, and you can delete unnecessary files on the fly.


The DSP (Digital Signal Processor) function allows you to add surround effects to your music signal through digital signal processing. You can also adjust the equalizer and reverb for each DSP mode you set.
You can choose from seven surround effects : hall, church, jazz club, stadium, disco, lybloom, and background music.

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 function of up to 24 songs, 8-mode repeat of 1 song / all songs / relay A-B (remote control only) / program / delete play / shuffle / delete shuffle / custom index, index search (remote control only), AMS and music search.

The display section has a 20-track music calendar.
The dimmer control allows you to adjust the brightness of the display to three levels, and the remote control's display mode allows you to switch between full light / partial light / off.

Equipped with an optical digital output.

Equipped with two line-out terminals, fixed and variable.
In addition, it is equipped with a headphone terminal with a lineout linked volume that flashes when the remote control is operated.

Wireless remote control is included.

Model Rating
Type CD Player
Frequency characteristic 2 Hz to 20 kHz ± 0.3 dB
Total harmonic distortion factor 0.0025% or less (EIAJ)
Signal-to-noise ratio 115 dB or more (EIAJ)
Dynamic range 100 dB or more (EIAJ)
Wow and flutter Below the measurement limit (± 0.001% W. peak) (EIAJ)
Output level 2Vrms(Fixed)
2 Vrms ~ 0 V (Variable)
Digital output Optical : -18dBm (emission wavelength 660 nm)
Headphone output level 28 mw (32 Ω)
Power consumption 15W
External dimensions Width 430x Height 110x Depth 355 mm
Weight 4.6kg
Attachment Wireless Remote Control RM-D997