SANSUI AU-D707F Extra
¥ 113,000 (released in 1981)
Commentary
An improved integrated amplifier based on the AU-D707F.
Super FF and diamond differential circuit are adopted for the power amplifier section.
The first stage is equipped with a constant-current differential circuit using a dual FET that allows a large current to flow with low noise, and the second stage is equipped with a dual complimentary service differential circuit. This increases the current supplying power to the power stage and supplies the necessary drive current to the power stage even for complex peak inputs.
The power stage adopts Super FF with improved accuracy and uses excellent materials such as NM-LAPT to achieve low distortion and high power.
To support MC cartridges, an MC head amplifier using a symmetrical circuit with two differential stages is mounted.
In addition, it is equipped with an input gain changeover switch to be compatible with all MC cartridges, and it can be switched between High position and Low position.
A new Hi-Precision equalizer has been incorporated in the equalizer amplifier section to cover the RIAA deviation of 20 Hz to 300 kHz ± 0.2 dB and improve the frequency response.
A low-noise, high-gm dual FET is used for the first stage, and a push-pull drive pure complimentary service SEPP outputs are formed by two stage differentials and current differentials with a current mirror. In addition, a DC servo is used to stabilize the DC region and to eliminate output capacitors.
In addition, a linear servo regulator is used in the power supply section of the equalizer, enabling a clean and stable power supply.
The power supply section is independent on the left and right and consists of two windings and three power supplies.
A large power transformer with excellent regulation is used for the transformer, and a newly developed α capacitor with a total capacity of 48,000 μ F is used for the capacitor. The α capacitor was newly developed for the AU-D907F Extra. It is an ultra low magnification type and has excellent follow-up performance even in transient charge and discharge.
In addition, all rectifier diodes use fast recovery diodes with fast switching speed to improve regulation response.
In order to reduce magnetic distortion, a copper plated chassis is used.
In addition, consideration is given to various aspects such as the use of a large number of NM elements and the construction which is less affected by magnetic strain.
In order to make the signal path the shortest distance, simple and straight construction is adopted.
An orderly construction is achieved by adopting a heat radiation system using heat pipes, three dimensional three dimensional wiring, and a remote controlled speaker output with relay.
A twin relay SP switch capable of connecting two systems is adopted.
It is equipped with a 16 hz subsonic filter and a 20 khz supersonic filter.
Gold plated terminal is used for phono input terminal.
Equipped with two independent source recording selectors and a two circuit tape monitor / copy function.
There are 2 color variations of black and silver.
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Model Rating
| Type | Integrated DC amplifier |
| Power Amplifier Unit (Super Feedforward & DD/DC System) | |
| Effective power | 100W + 100W (8 Ω, 10 Hz to 20 kHz, THD 0.003%) 100W + 100W (8 Ω, 1 khz, THD 0.002%) |
| 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 | ± 200 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) : 100 μ V/300 μ V (100 Ω) Tuner, Aux, Tape play1, 2 : 250mV/27k Ω |
| Phono maximum allowable input (1 kHz, THD 0.01%) | MM:200mV MC : 25 mV (low), MC head amplifier 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 : not more than 0.006% |
| 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 : 74 dB or more Tuner, Aux, Tape play1, 2 : 110 dB or higher |
| Phono input equivalent noise (A network, short circuit) |
Phono1, 2 mm : -142dBV Phono1, 2 mc : -154dBV |
| Channel Separation (1 kHz) | Phono1, 2 mm : 60 dB or more Phono1, 2 mc : 50 dB or more Tuner, Aux, Tape 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) | 250W |
| External dimensions | Width 460x Height 160x Depth 404 mm |
| Weight | 14.7kg |