SANSUI AU-D907F Extra

Commentary

Integrated amplifier improved as EXTRA version of AU-D907F.

SANSUI's unique Super Feed Forward System is used in the power amplifier section.
The AU-D907F EXTRA uses a MOS-FET for the error correction amplifier to further improve the quality of this circuit. The MOS-FET circuit has a switching speed five times faster than that of bipolar transistors, and is superior in broadband characteristics and temperature stability. This circuit improves the stability of the distortion cancellation signal produced by the error correction amplifier.
The pre-driver stage is equipped with a diamond differential circuit that minimizes TIM distortion to 0.

Linear step MC transformer is mounted to support MC cartridge.
This transformer is a reflection of Sansui's amplifier and transformer technologies. It uses a five layer Permalloy shield structure and 78% 0.1m/mL type Permalloy core. In addition, the thick winding is made into a balanced special winding structure. It is also equipped with microphonic shock noise prevention measures. This realizes a transformer with good dynamic characteristics, wide range and high SN ratio.
In addition, it is possible to switch between High impedance and Low impedance for all MC cartridges.

The power supply section uses a large transformer with a balanced winding made of a highly regulated C-I core. The capacitor is an original high-speed, ultra-low-power α capacitor produced by Shinkai. The 12,000 μ Fx4 creates low-frequency sound, while the 4,700 μ Fx4 α capacitor enhances medium-frequency sound. In addition, a fast recovery diode is used to increase playback speed.
In addition, a total of five power supply structures are employed to achieve independence of the left and right sides and to eliminate interference between stages.

The equalizer circuit uses a DC amplifier configuration of a diamond differential circuit.
The first stage consists of a cascode bootstrap circuit that is not affected by input impedance by using a differential circuit using dual FET of low noise and high gm with good pair characteristics. The second to third stage consists of a diamond differential circuit with excellent drive capability and current differential push-pull. The output stage has a sufficient current margin by using a SEPP circuit with Darlington connection. The low output impedance and low impedance NF circuit provide a sufficient dynamic range even when load impedance changes, and the S / N ratio is also improved.
In addition, a DC servo is employed to eliminate output capacitors while stabilizing the DC region.

Uses material and construction to eliminate magnet distortion.
In the AU-D907F EXTRA, the chassis is made non-magnetic by copper plating, and magnetic strain is removed from the frame of the amplifier. In addition, the heat loop is placed in the center, and it is a construction which can concentrate on avoiding magnetic flux by releasing from the effect of heat generation, etc..
In addition, we have taken thorough measures against magnet distortion by adopting NM (non-magnetic) elements, etc.

Equipped with a 16 hz subsonic filter and a 20 khz supersonic filter.

The tone control is equipped with a turnover frequency switching function.

Equipped with a recording selector with two independent sources and a two circuit tape monitor / copy function.

Uses real wood side panels.

Uses a gold plated phono input terminal.

Model Rating

Type	Integrated DC amplifier
Power Amplifier Unit (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, Tape 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 : 75 dB or more (Low) Tuner, Aux, Tape play1, 2 : 110 dB or higher
Phono input equivalent noise (A network, short circuit)	Phono1, 2 mm : -142dBV Phono1, 2 mc : -155dBV
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)	320W
External dimensions	Width 460x Height 160x Depth 444 mm
Weight	17.7kg