SONY CDP-XA55ES

Commentary

This is the last CD player in the ES series equipped with a variable digital filter and enhanced power supply.

An optical system fixing mechanism is adopted for the mechanism part.
In this system, the pickup is fixed to a solid base and the disk moves on the mechanical base, so that vibration of the pickup is sharply reduced and the current required for servo operation is relatively slow to compensate for disk distortion and eccentricity.
In addition, the CDP-XA55ES uses a zinc die-cast base for fixing the optical pickup to reduce the resonance of the base itself and improve the reading accuracy. The CDP-XA55ES also uses a BSL motor for rotating the disc, which has less rotational unevenness.

The digital filter is equipped with a 24 bit variable digital filter.
In the variable digital filter, you can select filter characteristics according to your preference by registering multiple calculation formulas with different cutoff characteristics and phase characteristics.
In CDP-MS1, 24-bit processing is realized by using the newly developed device VC24. The processing capability as a digital filter is greatly enhanced by increasing the calculation speed and expanding the coefficient simultaneously in addition to greatly expanding the calculation vocabulary. There are five positions to choose from. In addition to the standard position with sharp roll-off characteristics, you can choose No1 clear, No2 plain, No3 fine, or No4 silky with slow roll-off characteristics.

The D/A converter is equipped with a current pulse D/A converter.
In this method, a stable current source is prepared, and the current pulse is generated by switching using the output of the pulse generator. By using the current pulse, the influence of fluctuation of the power supply voltage and voltage noise of the digital arithmetic circuit is eliminated.

The power supply section uses an R-core transformer with greatly reduced magnetic flux leakage and vibration.
The CDP-XA55ES uses a triple-R core transformer for audio circuits, digital circuits, mechanism drives, and a dedicated transformer for each circuit block to completely eliminate interference from each circuit block that passes through the power supply. Furthermore, for audio circuits, a large R core transformer that far exceeds the required capacity is used to secure spare capacity. The mechanism drives, which have relatively large fluctuations in power supply, are enclosed in a shield box.
The entire transformer is mounted on a non-magnetic copper plate with a low resonance frequency to keep the chassis magnetically clean by keeping a distance from the chassis and preventing stray magnetic fields.

It uses an enhanced servo circuit.
In CD players, the reflection light from the optical pickup is read out as an RF signal from the disc. However, the reflectivity changes depending on the condition of the disc and the RF signal fluctuates. This fluctuation can be cut off by using a powerful filter. However, the CDP-XA55ES emphasizes that the music signal to be extracted also fluctuates at the same time. It is equipped with a servo circuit that gives priority to the faithful pickup of the music signal without using a strong filter. This reduces the reading error caused by the disc side and achieves high reproducibility. This circuit is a luxurious design composed of discrete components.
In addition, the servo of the spindle motor that rotates the disk is equipped with a circuit that cancels the offset value of the Hall element that detects the rotation state. This stabilizes the detection capability and further reduces torque unevenness.

A high-precision digital servo is used in the servo section, and by adjusting the servo amount of the optical pickup for each disc to be played, servocontrol reflecting disc conditions more accurately is realized.

A center mechanical mounting system has been adopted for the internal layout, and the mechanical deck, which is the only mechanical operation section of the CD player, is placed in the center of the chassis to minimize the rotational moment applied to the chassis and improve the stability against vibration.

The FB chassis is used for the chassis, and the whole chassis is firmly fixed as one box by a frame (Frame = frame) surrounding the outer circumference and beams (Beam = beam) passed in front and back. By combining members of different shapes and sizes, natural vibrations are mutually cancelled, and vibration of the chassis as a whole is greatly reduced.

An eccentric insulator is used for the legs.
This insulator has a structure in which the mounting hole of the chassis is offset from the center, and the vibration transmitted to the chassis is reduced by mutually canceling the vibration transmitted from the outside.

A fine drive circuit is adopted, and noise contamination to the earth line is prevented by configuring the disk rotation system and the drive circuit of the optical pickup with balanced push-pull capable of canceling in-phase noise.
In addition, a digital minimum board has been adopted to reduce the impact on the audio section by arranging the digital circuit board in the minimum volume, separating it from the audio circuit board and placing it on the mechanical deck.

A static lighting FL tube that does not blink is adopted for the part where there is no change in the display to reduce the noise generated in the display.

It uses a jog dial type AMS to improve operability.

Equipped with a custom edit function, you can control functions such as peak search, time edit, just edit, program edit, time fade, manual fader and variable fade.

It is equipped with the custom file function of the maximum supported number of 224 sheets, and operations such as custom index and delete bank are possible.

It is equipped with various functions such as shuffle play, delete shuffle, delete play, autospace, timer play (auto start), 8-mode repeat and index search.

Equipped with a headphone port with volume that can also be used for lineout.

Equipped with 2 digital outputs, optical and coaxial.
The digital output can be turned off to prevent interference with the analog output.

Wireless remote control is included.

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* Internal Layout
In the catalog when it was released in 1998, there is a picture of the power transformer for driving the mechanism enclosed in a shield box and description of the features, but in the catalog after 1999, there is no picture or description of the shield box.
The shield box may have been used only for the model at the time of making the catalog such as the initial release model. I will post 2 layouts just in case.

Model Rating

Type	CD Player
D/A converter	Current pulse D/A converter
Digital filter	Variable digital filter
Frequency characteristic	2 Hz to 20 kHz ± 0.3 dB
Dynamic range	100 dB or more (EIAJ)
Total harmonic distortion factor	0.0017% or less (EIAJ)
Wow and flutter	Below the measurement limit (± 0.001% W. peak) (EIAJ)
Digital output	Light : -18dBm (emission wavelength 660 nm) Coaxial : 0.5Vp-p/75 Ω
Analog output	Fixed : 2 Vrms Variable : 2 Vrms to 0 Vrms
Headphone out	28 mw (32 Ω load)
Pwer	100 VAC, 50Hz/60Hz
Power consumption	20W
External dimensions	Width 430x Height 125x Depth 375 mm
Weight	Approx. 13.2 kg
Attachment	Wireless Remote Control RM-D950

　

Position and outline of variable digital filter

Position	Cutoff characteristic	Sound impression
Sharp roll-off
Standard		It has the largest amount of information and is characterized by its wide range and spatial expression. Suitable for playing classical music.
Slow roll-off
No1 Clear		It a smooth touch and energy feeling, sound image localization is clear. Suitable for jazz band, jazz vocal, etc.
No2 Plain		It is fresh and energetic, and especially rich in expressive power of the luster of vocals. It is suitable for vocal music.
No3 Fine		It has a balanced natural sound with a sense of scale and rich reverberation. Perfect for enjoying a relaxed mood regardless of the genre of music.
No4 Silky		It combines a sense of scale and sensitivity. It is suitable for playing music that combines vocals such as opera and background music.