The technical explanation of Model_2

Inside photograph of Model_2

This photograph is only for the explanation. Never open the cabinet because there is a high voltage parts in the inside.

1.The advanced digital circuit which reproduces 96KHz, 24bit sampling data

The digital audio signal on the coaxial or TOS input is received with CS8414 DAIR IC. This IC can receive a digital audio signal of the sampling frequency from 32KHz to 96KHz and the data length from 16 bits to 24 bits. In addition, the stable music can be reproduce because of an excellent jitter characteristic of CS8414.

The digital filter of Model_2 possesses 8fs operation at 96KHz sampling. A lot of other DAC work on an operation of 4fs at 96KHz sampling. Model_2 is excellent.

For conversion from digital to the analogue, we chose PCM-1716 of multi bit Delta-Sigma method DAC of Burr-Brown Corporation. PCM-1716 can reproduces accurately 96KHz 24bit sampling data. It's multi bit Delta-Sigma DA conversion part is the combination of 64fs over sampling filter and 4th Noise shaper and 8 level (3bit) DAC. Because of multi bit Delta-Sigma DA conversion, Model2's accuracy and jitter characteristic are more excellent than a simple 1bit DAC. Similar multi bit Delta-Sigma DA conversion to Model2 is a fashion recently. Famous dCS952 and Elger use multi bit Delta-Sigma DA conversion for the studio and Hi-end.

Comparing Model_2 and dCS952,Elger
dCS952, Elger
Over sampling 64fs 64fs (96KHz is 32fs)
Noise shaper 4th 4th
Base DAC bits 3bitDAC 5bitDAC

Model_2 has the same composition as the studio equipment for the professional.

2.Error display and error counter

The following seven kind of reading and transmission errors are displayed.
Validity Bit Hi, When the reading error had occurred, the interpolation processing was done. The data which has reproduced is not true data.
Confidence Flag This indicates that the quality of the optical cable and the coaxial cable are poor and do not meet the digital audio interface standards.
Slipped Sample This indicates that the data was not able to be received according to the clock. (This error will be detected when the external synchronization option is installed in the future)
CRC Error There is a mistake in control information. It is a fault in the software production, This error does not influence the reproduction sound.
Parity Error There is a mistake in data. Parity does not collate. The cause is in bad condition of the player.
Bi-phase Coding Error A digital audio signal is not correctly composed( does not meet the rule of the Bi-phase Coding). The cause is in bad condition of the player.
No Lock A digital audio signal is not be reproduceable sampling frequency or the signal is not provided.

When the error occurs, the lamp lights for one second , the error which occurs sporadically can be confirmed.

Model_2 has the four digits counter which counts the number of the errors. It is convenient for the detection of the state of the reproduction system and the wound of CD, DVD.

The error counter which made by static circuit does not operate if the error does not occur. So it does not influence tone quality in normally reproducing.

3.The non negative-feedback analog circuit by vacuum tube

All analog circuits after DAC IC are composed of vacuum tubes. The analog circuit has 2 stages: low-pass filter (LPF) which removes the high frequency noise and output buffer. The LPF is CR 2nd filter, and the output buffer is simple cathode-follower-amplifier. The circuit is directly connected from the output of DAC IC to cathode-follower-amplifier. there is only one coupling capacitor, which causes the tone quality deterioration, between the output buffer and the output terminal. The high concise circuit structure and the good stability of non negative-feedback circuit make the excellent tone quality.

4.Stabilized power circuit

A good quality power supply is necessary to reflect the goodness of the vacuum tube in tone quality. Model_2 has four stabilization power circuits.

  1. 5V power supply for digital circuit
  2. Low-voltage stabilization power supply for analogue part of DAC IC
  3. 150V high-voltage stabilization power supply for vacuum tube analog circuit
  4. 6.3V stabilization power supply for filament of vacuum tube

5.Excellent parts

Hight quality parts are used for Model_2.
Latest digital IC, high quality glass-epoxy circuit board, large-power resistor, large-size film capacitor, high voltage mica capacitor, vacuum tube sokets with gold plated pin, gold plated RCA jacks.