Audio Database

D-107U
Commentary

A CD player with a 3-pole vacuum tube for output circuit.

Bi-triode 6CG7 is adopted as cathode follower circuit.
The 3-pole vacuum tube has linear characteristics and excellent ability to draw out music, such as less harsh odd-order harmonics. In addition, the cathode follower, in which the active element is composed of the minimum unit (1 unit), simplifies the circuit.

An output line transformer newly developed for the D-107U has been adopted.
As well as enabling advanced musical expression, the transformer coupling realizes stable transmission even under low impedance loads.

By utilizing the natural attenuation characteristics of the line transformer, we have succeeded in completely removing the analog filter, which is harmful to sound quality. This realizes a simple circuit configuration in which the analog signal enters the vacuum tube directly after the DA conversion and is output through the output transformer.

In order to prevent the CD player from outputting pulses when the power is turned on, a muting circuit is used to prevent the CD player from outputting pulses for a certain period of time.
This muting circuit uses relay contacts, making it an ideal output circuit in which the ground line and the DC line are completely disconnected when the muting is released.

Digital output is eliminated in order to thoroughly pursue the taste of analog circuits using vacuum tubes.
In addition, it is equipped with 2 systems of variable output and fixed output by electric volume, and both systems realize pure line out which is not affected by radiation.

Anti-vibration measures are provided to suppress external vibration that is harmful to sound quality.
The optical pick-up base is separated from the assembly base, and a special rubber damper and coil spring are combined between them to block vibration. It uses a unique high-rigid lock mechanism.
In addition, a center-mounted low center of gravity structure, which is placed in the center, makes the structure resistant to external vibration.

Built-in editing and fade-out functions are useful for recording.
It is also equipped with a time fade-out function that allows you to specify the time, and you can set the fade-out time up to 99 minutes in units of minutes.
When time comes, it fades out naturally and then returns automatically to the initial output level.

Equipped with a preheating switch that warms the vacuum tube heater in advance, stable operation can be obtained in a short time.

Equipped with a display adjustment function that can adjust or turn off the brightness of the FL display tube according to the brightness of the room.

Uses gold-plated terminal with low contact loss.

Model Rating
Type CD Player
Pick-up Semiconductor laser pickup
Number of quantization bits 16-bit linear formula weight threading
Sampling frequency 44.1kHz
Frequency characteristic 20 Hz to 20 kHz, ± 1 dB
Output voltage 2.0V
Dynamic range 89dB
Signal-to-noise ratio 105dB
Channel separation 86dB
Wow flutter Measurement limit value or less
Harmonic distortion factor 0.09%(1kHz)
Power supply voltage 100 VAC, 50Hz/60Hz
Power consumption 28W
External dimensions Width 470x Height 147x Depth 342 mm
Weight 10.3kg