SANSUI AU - α 777 dg
¥ 96,500 (around 1989)
Commentary
A pre-main amplifier with a Mash D/A converter.
The New L. D. C. S (linear & direct D/A conversion system) based on the Mash method is installed in the D to A converter section.
The Mash method is a D/A conversion method that uses the frequencies of a crystal oscillator as the conversion standard. It uses high-order oversampling and third order noise-shaping to instantaneously convert digital signals into high-precision analog signals, and has the feature that 0 cross distortion and nonlinear distortion do not occur in principle.
In order to take advantage of the high accuracy of the Mash system, the AU-alpha 777 dg has an accuracy close to that of a crystal oscillator and uses a lithium tantalate device with a wide lock range, making it a unique linear & direct D/A conversion system (L. D. C. S).
The New L. D. C. S further improves the S / N ratio by upgrading all peripheral circuits.
The power supply section is completely separated from the power supply section by installing dedicated transformers for both digital and analog circuits.
This prevents electromagnetic pulses peculiar to digital from mixing into the analog part.
The amplifier section uses an α -X balanced circuit with unique know-how, and the circuit itself cancels noise and distortion by balance operation.
A twin monaural construction with the power supply in the center and the power units symmetrically arranged ensures that the digital section to be shielded outside the left channel unit and the analog input section to be shielded outside the right channel unit so that the digital and analog sections are clearly separated.
In order to achieve both sound quality and convenience, it comes with a remote controller that uses a direct access rotary switch. It is possible to increase or decrease the volume by 6 connected volumes and switch the source.
It is equipped with functions such as source direct operation, REC selector and direct access rotary switch.
Uses gold-plated input terminal, very thick power cord with polarity display, and AC outlet.
There was a side wood sold separately.
Model Rating
Type | Α -X Balanced Integrated Amplifier |
Digital Part | |
Frequency characteristic | 4 Hz to 20 kHz ± 0.5 dB |
Signal-to-noise ratio | 108 dB or more (EIAJ) |
High frequency distortion factor | Not more than 0.003% |
Digital input level | 0.5Vp-p/75 Ω |
Optical input | 660 nm (emission wavelength) |
Power Amplifier Unit | |
Effective output (10 Hz to 20 kHz Both channel operation) |
105W + 105W (6 Ω) 90W + 90W (8 Ω) |
Dynamic Power | 230W (2 Ω) 220W (4 Ω) 155W (6 Ω) |
Total harmonic distortion factor (at effective output) | 0.003% or Less (8 Ω) |
Cross modulation distortion factor | 0.003% or Less (8 Ω) |
Damping factor | 150 (8 Ω) |
Frequency Response (1W) | DC ~ 200 khz + 0 -3dB |
TIM (SAWTOOTH) | Measurement limit value or less |
Slew rate | 180 V / μ sec |
Rise time | 0.6 μ sec |
Preamplifier Section | |
Input Sensitivity / Impedance (1kHz) |
Phono MM : 2.5mV/47k Ω Phono MC : 300 μ V/100 Ω CD, Tuner, Line, Tape/DAT1, 2, 3 : 150mV/20k Ω |
Phono maximum allowable input | MM(THD 0.01%):210mV MC(THD 0.1%):21mV |
Frequency characteristic | Phono MM : 20 Hz to 20 kHz ± 0.2 dB CD, Tuner, Line, Tape/DAT1, 2, 3 : DC ~ 200 khz + 0 -3dB |
Signal-to-noise ratio (A network) | Phono MM : 88 dB or more Phono MC : 70 dB or more CD, Tuner, Line, Tape/DAT1, 2, 3 : 110 dB or more |
Tone control | Bass : ± 6 dB (50 Hz) Treble : ± 6 dB (15 kHz) |
Subsonic filter | 16 Hz (-3dB), 6dB/oct. |
Loudness | + 6 dB (50 Hz), + 4 dB (10 kHz) |
<General> | |
Rated power consumption | 250W |
External dimensions | Width 430x Height 163x Depth 450 mm |
Weight | 18.2kg |
Attachment | Wireless Remote Control RS 1130 |
Sold Separately | Real Side Wood SW-AU1 (¥ 10,000) |