SANSUI AU-D907X Decade

Commentary

This is an integrated amplifier based on the AU-D907X. The power supply has been reinforced to improve the reproduction capability in the low frequency range.

The basic configuration of the amplifier is a twin diamond X balanced amplifier.
In the conventional amplifier, the current to the speaker is sent from the positive side and the negative side is simply connected to the ground. Therefore, when the back electromotive force flows into the ground on the negative side, IHM distortion occurs due to mutual interference with the ripple current of the current. In addition, NFB for reducing the distortion is only on the positive side, and the negative side is not controlled at all.
The Twin Diamond X balanced amplifier has a balanced configuration for all signal circuits from input to output, power supply circuits, and NFB circuits. By driving the speakers equally from both + and - sides, the influence of ground is eliminated.
In addition, in order to make the power transistor work more effectively, the speaker drive capability has been improved by adopting a two stage configuration in which the power transistor is driven by current using a twin diamond differential circuit.

The power supply section features a 10.7 kg super-heavyweight power transformer and four high-quality capacitors.
In addition to the balanced power supply system, the pre-drive and power sections and L/R sections of the power amplifier section are independent to improve stability.

Equipped with a CD direct input terminal, pure CD playback is possible without passing through the input selector.

The main electrolytic capacitors are high-quality and high-performance type, and the small-capacity film capacitors are made of Styrofoam copper foil.
In addition, it uses resistance with excellent sound quality without resonance.

It uses a large and heavy aluminum block heat sink with excellent heat radiation effect and prevention of modulation distortion due to vibration without power transistor.

In addition to the High-MC position directly connected to the equalizer, the MC-High position and MC-Low position using an MC transformer are equipped.
The MC transformer uses two monaural types using super permalloy cores made by Magnetic INC (USA) with excellent magnetization characteristics.

The equalizer is equipped with a high-precision equalizer using a diamond differential circuit.

Equipped with Rec selector.

Model Rating

Type	Integrated DC amplifier
Power Amplifier Unit
Effective output (10 Hz to 20 kHz, both channels driven)	190W + 190W (6 Ω) 160W + 160W (8 Ω)
Total harmonic distortion rate (10 Hz to 20 kHz)	0.003% (8 Ω, Effective Output) 0.005% (6 Ω, at 1/2 effective output)
Intermodulation distortion factor (60 hz : 7 khz = 4 : 1)	0.003% (8 Ω, Effective Output)
Output Bandwidth (IHF, both channel operation, THD0.03%)	5 Hz to 80 kHz
Damping factor (new IHF, 20 Hz to 20 kHz)	100 (6 Ω)
Frequency Response (1W)	DC ~ 300 khz + 0 -3dB
Slew rate	± 300 v / μ sec (6 Ω)
Rise time	0.5 μ sec
Equalizer Amplifier Section
Input Sensitivity / Input Impedance (1 kHz)	Phono MM : 2.5mV/47k Ω Phono High MC : 2.5mV/100 Ω Phono MC Low : 100 μ V/3.2 Ω (Uses MC transformer) Phono MC High : 300 μ V/40 Ω (Uses MC transformer) CD, Tuner, Tape1, 2/PCM, CD Direct : 150mV/47k Ω
Phono maximum allowable input (1 kHz, THD 0.01%)	MM:300mV High MC:300mV MC High : 35 mV (Transformer Type)
Signal-to-noise ratio (A network, short circuit)	Phono MM:90dB Phono MC:80dB CD, Tuner, Tape : 110 dB
<General>
Rated power consumption (Electrical Appliance and Material Control Law)	370W
External dimensions	Width 466x Height 161x Depth 431 mm
Weight	26.0kg