SANSUI AU - α 907L Extra
¥ 250,000 (around 1989)
Commentary
This is the top pre-main amplifier of the LExtra series that uses LAPT which is a transistor only for audio.
To improve linearity at low levels, it is equipped with LAPT (Linear Amplification Power Transistor) newly developed for audio only.
The LAPT is made of pure copper. By making the bonding wires nonmagnetic, the generation of magnetic distortion is eliminated. This greatly improves the cut-off frequency and broadens the band, while improving the linearity of current amplification factor and switching characteristics.
A -X balanced circuit is used for the circuit structure, and a NEW diamond differential circuit with cascade connection of first stage FETs provides excellent high-frequency characteristics.
The power supply section is placed in the center and the power amplifier section mounted on a large heat sinker is arranged symmetrically in a twin monaural construction. This eliminates interference from vibration sources that adversely affect sound quality, and achieves excellent sound localization.
The AU - α 907L Extra uses solid pure copper large insulators, LAPT absorbers, and pure copper parts such as transformer base in order to ensure no vibration and no resonance.
The power supply section has a balanced power supply structure, and various adverse effects are suppressed by making it a closed loop which is independent from ground.
In addition, newly developed large transformers filled with high-density fillers, power capacitors, fast recovery diodes, and other newly developed custom-made products are used to achieve low impedance and high speed.
We use carefully selected parts, including capacitors, resistors, semiconductors, coils and other parts that allow music signals to pass through directly.
The equalizer section is equipped with a full-scale discrete phono equalizer.
Equipped with a balanced input.
Equipped with functions such as power amplifier, direct, source direct, and REC selector.
The volume is equipped with 6 continuous detent volume.
Model Rating
Type | Α -X Balanced NM-LAPT / Amplifier |
Power Amplifier Unit | |
Effective output (20 Hz to 20 kHz Both channel drive) |
190W + 190W (6 Ω) 160W + 160W (8 Ω) |
Dynamic Power | 580W (2 Ω) 390W (4 Ω) 310W (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 ~ 300 khz + 0 -3dB |
Input Sensitivity / Impedance | 1V/3k Ω (1 kHz) |
Signal-to-noise ratio (A network) | 120 dB or more |
TIM (SAWTOOTH) | Measurement limit value or less |
Slew rate | 200 V / μ sec |
Rise time | 0.5 μ sec |
<Pre-part> | |
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%):250mV MC(THD 0.1%):25mV |
Frequency characteristic | Phono MM : 20 Hz to 20 kHz ± 0.2 dB CD, Tuner, Line, Tape/DAT1, 2, 3 : DC ~ 300 khz + 0 -3dB |
Signal-to-noise ratio | Phono MM : 90 dB or more Phono MC : 75 dB or more CD, Tuner, Line, Tape/DAT1, 2, 3 : 110 dB or more |
Tone control | Bass : + / - 5 dB (50 Hz) Treble : ± 5 dB (15 kHz) |
Subsonic filter | 16 Hz (-3dB), 6dB/oct. |
Loudness | + 4 dB (50 Hz), + 3 dB (10 kHz) |
<General> | |
Rated power consumption | 400W |
External dimensions | Width 472x Height 164x Depth 450 mm |
Weight | 33.0kg |