SANSUI AU-D907G Extra
¥ 178,000 (released in 1983)
Commentary
This integrated amplifier is based on the AU-D 907 au-D f Extra.
Newly developed ground floating circuit is mounted.
This circuit was developed after reviewing the ground circuit of the amplifier. The output amplifier, load (speaker) and power circuit are completely closed loop. In addition, the power supply section is a floating power source, and the power transformer winding is made independent by plus and minus, each of which is rectified by two bridges. This circuit eliminates the interference of the input, output and power in the ground circuit.
As a result, IHM distortion which is harmful to sound quality is minimized.
The power supply consists of five independent power sources : an equalizer / tone amplifier, Lch and Rch in the pre-drive stage of the power amplifier, and Lch and Rch in the power stage. The pure focus condenser used in the B-2301 is used as the electrolytic condenser to improve the quality of the playback sound.
A linear step MC transformer is installed to support MC cartridges.
This transformer is based on the AU-D907F Extra and refined, and uses high-grade permalloy core made by Magnetic Ink Co., Ltd. with extremely high purity. In addition, distortion is suppressed by special annealing.
In addition, the load impedance of the MM cartridge and MC cartridge is completely independent, and the optimum load is installed to enable amplification with higher purity.
The power amplifier section is equipped with a super FF and a diamond differential circuit.
The Super FF is a circuit that combines the advantages of NFB and feed-forward. It produces a signal with the opposite phase to the distortion that cannot be canceled by NFB with an error collection amplifier, and cancels the distortion with the output. In addition, the AU-D907G Extra uses a MOS-FET with a high-speed capability that is five times higher than that of a bipolar transistor in the error collection amplifier to improve the distortion removal capability.
A diamond differential circuit is adopted in the pre-drive stage, and by making the current margin extremely large, a sufficient current margin is provided even for a large transient input, and high-speed response of the drive stage is realized.
The OCL equalizer circuit of DC servo configuration with a diamond differential circuit is mounted in the equalizer amplifier section, and realizes an ultra-wide range and high precision with RIAA deviation of 20 hz to 300 khz ± 0.2 db.
In order to eliminate magnetic distortion, both materials and structures have been considered, such as adoption of copper-plated chassis and NM (non-magnetic) elements, and construction to avoid electromagnetic flux.
Input terminals for DA and PCM are mounted.
Equipped with AC power cord with polarity display.
Equipped with a subsonic filter and a supersonic filter.
Equipped with tone control with turnover frequency switching function.
Equipped with a recording selector with two independent sources and a two circuit tape monitor / copy function.
Gold plated terminal is used for phono input terminal.
There are 2 color variations of silver and black.
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Model Rating
| Type | Integrated DC amplifier |
| Power Amplifier Section (Ground Floating, Super Feedforward & DD/DC System) | |
| Effective power | 130W + 130W (8 ohm, 10 hz to 20 khz, THD 0.003%) 130W + 130W (8 ohm, 1 khz, 0.002% THD) |
| Total harmonic distortion factor (10 Hz to 20 kHz at effective output) | 0.003% or Less (8 Ω) |
| Intermodulation Distortion Factor (60 Hz : 7 kHz = 4 : 1, SMPTE) | 0.003% or Less (8 Ω) |
| Output Bandwidth (IHF, both channel operation, THD 0.02%) | 5 Hz ~ 80 kHz (8 Ω) |
| Damping factor (new IHF, 20 Hz to 20 kHz) | 100 (8 Ω) |
| Frequency Response (1W) | DC ~ 300 khz + 0 -3dB |
| Envelope distortion | Below the measurement limit |
| TIM Strain (Sawtooth method) | Below the measurement limit |
| Slew rate | ± 250 v / μ sec (8 Ω) |
| Rise time | 0.5 μ sec |
| <Equalizer amplifier (Hi-Precision DC servo equalizer)> | |
| Input Sensitivity / Input Impedance (1 kHz) | Phono1, 2 mm : 2.5mV/47k Ω Phono1, 2 mc (Low/High) : 70 μ V (3.2 Ω) / 250 μ V (40 Ω) Tuner, Aux/DA, Tape/PCM play1, 2 : 250mV/27k Ω |
| Phono maximum allowable input (1 kHz, THD 0.01%) | MM:200mV MC : 25 mV (low), transformer system |
| Output Level / Impedance (1 kHz) | Tape rec (PIN) : 250 mv (47k Ω) / 600 Ω |
| Total harmonic distortion factor (20 Hz to 20 kHz at 5 V output) | Phono1, 2 MM : not more than 0.005% Phono1, 2 mc : Transformer system |
| RIAA Deviation (MM, Rec out) | 20 Hz to 300 kHz ± 0.2 dB |
| Signal-to-noise ratio (A network, short circuit) | Phono1, 2 mm : 90 dB or more Phono1, 2 mc : 81 dB or more (70 μ V) Tuner, Aux/DA, Tape/PCM play1, 2 : 110 dB or more |
| Phono input equivalent noise (A network, short circuit) |
Phono1, 2 mm : -142dBV Phono1, 2 mc : -161dBV |
| Channel Separation (1 kHz) | Phono1, 2 mm : 60 dB or more Phono1, 2 mc : 50 dB or more Tuner, Aux/DA, Tape/PCM play : 80 dB or more |
| Tone control | Bass : ± 10 dB (50 Hz) Treble : ± 10 dB (10 kHz) |
| Tone selector | Bass : 150 Hz, 300 Hz Treble : 3 kHz, 6 kHz |
| Filter | Low : 16 Hz (-3dB, 6dB/oct.) High : 20 kHz (-3dB, 6dB/oct.) |
| Audio Muting | -20dB |
| <General> | |
| Rated power consumption (Electrical Appliance and Material Control Law) | 320W |
| External dimensions | Width 460x Height 160x Depth 444 mm |
| Weight | 18.0kg |