ONKYO Integra C-901XD

Commentary

A CD player with an 18-bit super-real optical converter and optical transmission system.

It is equipped with an 18-bit optical converter that uses electrical energy generated by light energy as the constant current source of the D/A converter, which is the source of music signals. In addition, it is equipped with dual optical converters that support the left and right D/A converters, each with its own constant current source.
In the optical converter, the constant current source is separated from the power supply of other digital and analog circuits, so that high purity transmission without interference from external noise is possible.

The D/A converter is equipped with an independent 18-bit super-real D/A converter for the left and right.
The ladder type 18-bit D/A converter has sufficient quality even when used without adjustment. Normally, only the heaviest bit (1 bit) is adjusted. However, the C-901XD is adjusted by 4 bits each on the right and left sides to realize more accurate D/A conversion.

An optolink module and a photocoupler, which connect optical transmission and receiving elements with optical fibers, are selected according to the transmission speed. By transmitting light through all six signal paths, the loop is electrically disconnected and digital noise is eliminated.

The digital filter uses an 8 x oversampling digital filter to shift the sampling frequency from 44.1 frequency from kHz to 352.8 kHz, 8 times the sampling frequency, and reduces the cutoff characteristics of the low-pass filter, which can cause sound quality degradation.
In addition, this 8 x oversampling digital filter outputs 8 times as much data as the original audio signal, so you can enjoy the quality of the original sound that does not pass through the low-pass filter from the output of DAC direct (immediately after D/A conversion).

In order to suppress the effects of acoustic feedback and vibration from the floor, we have developed a box structure (double chassis) that is fully tightened to the front, back, left and right sides to increase rigidity. In addition, we have adopted a double chassis as a base, which absorbs vibration propagated from the bottom plate and chassis by two special damping materials sandwiched inside the box structure.

The main body of the mechanism is a highly rigid chassis with a resonance dispersion structure that combines a 1.6 mm chassis with an outsert compound molded product. In addition, the sub-chassis mounted on the pickup has the same structure as the main body. It is separated from the main body chassis, and vibration control in both vertical and horizontal modes is performed by special spring and silicon rubber.
In addition, the chassis of the mechanical body is attached to a high-rigidity double chassis separated by a non-resilient rubber and a double isolated system is adopted, which reduces internal vibration and speaker vibration.

The pickup is driven by a newly developed linear slide motor mechanism with less vibration.

To prevent magnetic flux from the power supply, a separator is installed between the power supply block and the electronic circuit block. The top cover is also a two piece structure to completely separate the two blocks. A separator is also installed between the digital circuit block and the analog circuit block to reduce digital noise.

The power supply section has a two transformer configuration with a transformer for digital and analog only. The audio transformer has a capacity margin of 300%.

It is equipped with two digital outputs, coaxial and optical, and analog outputs of fixed, variable and direct Route 3.
In particular, the analog direct connector allows direct output from the D/A converter without passing through an analog low-pass filter.

Equipped with a random double calendar.

It is equipped with gold plated headphone terminal and output level volume.

Wireless remote control is included.

Model Rating

Type	CD Player
Sampling frequency	352.8 kHz (8 x oversampling)
Frequency characteristic	2 Hz to 20 kHz ± 0.5 dB
Harmonic distortion factor	0.0015%(1kHz)
Dynamic range	103dB
Signal-to-noise ratio	110dB
Wow flutter	Below Measurement Limit (Crystal Accuracy)
Output level (analog)	2 vrms (fixed, variable, direct)
Pick-up	Semiconductor laser pickup (3-beam system)
Digital output terminal	2 systems (coaxial, optical)
Line output terminal	Route 3 (fixed, variable, direct)
External dimensions	Width 435x Height 131x Depth 365 mm
Weight	9kg
Attachment	Wireless Remote Control