SANSUI AU-X1111MOS VINTAGE

Commentary

This is the last amplifier in the X series that started with AU-X1.

Earth-based amplifiers drive the speakers between the output of the amplifier and the ground, so they are susceptible to noise and distortion from the ground, which degrade sound quality.
In order to solve this problem, we have adopted a balanced circuit that is not grounded. In this circuit, the - side of the speaker is double-push-pull driven in both directions under the same conditions as the + side. This eliminates unnecessary high-frequency components such as noise and distortion, and realizes an excellent sound image at a low distortion rate.
In addition, there is no noise from the power supply and no IHM (Interface Hum Modulation) caused by back electromotive force from the speakers.
It also supports changes in the impedance and phase of speakers.

The power supply circuit that operates the balanced circuit is also a closed loop with no connection to the ground circuit.
In addition, we have achieved low impedance and high speed in the entire power supply by adopting a newly developed heavy-duty transformer that has been carefully examined from the viewpoints of sound quality and electrical performance without simply pursuing a sense of weight. We have also examined various aspects from capacity to core material and winding material. We have also selected custom-made electrolytic capacitors for audio and fast recovery diodes.

In order to prevent noise from connected digital devices, we do not insert a line filter. Instead, we use a unique balance transmission method from the signal circuit including the power stage to the power supply circuit.
In the signal path, the + side and the - side are transmitted in a balanced manner so that hum and noise components can be canceled. Moreover, the ground is separated from the - side so that it is not affected by hum and noise components.
As a result, the S / N ratio and transparency of the sound are improved.

The twin monaural construction is based on the concept of a separate power amplifier. The power supply section centered on a large power transformer is placed in the center, and the power amplifier section mounted on the heat sinker is separated symmetrically. This effectively improves crosstalk between L/R units and interference between power supply system vibration and music signal.
In addition, the master volume and the left and right volumes are completely independent.
In addition to improving the shielding characteristics between stages and eliminating mutual interference of signals, the effects of external digital electromagnetic noise and magnetic distortion are also eliminated.

The power MOS FET, power transformer and master volume are mounted on a pure copper plate. The bottom plate is shielded by copper plating. A large insulator made of pure copper muku covered with felt is also used to reduce the influence of the ground surface on sound quality. Thus, detailed measures against vibration are taken.

A total of 16 MOS FETs are used in the diamond power stage, and four double-push-pull FETs are used in four places on the left, right and + - sides of the power stage.

It is equipped with an image input terminal is compatible with switching and dubbing of images when a VTR is connected.
To cope with the problem that high-frequency components of video signals adversely affect sound quality, the video signals are processed by IC switches on the back of the pin jacks on the rear panel without any wiring inside the chassis.
In addition, the power for the IC is supplied from a transformer separate from the audio system, and a single ON/OFF switch is provided. Thus, the cross point between the audio and video signals is completely separated physically and electrically.

In order to pursue the real quality of design, wood panels made of real rosewood are used on both sides and the top. In addition, front glass panel and shower light are used.

Equipped with a presence control function that slightly raises the middle and low band energy without changing the tone even when playing back at a low volume.

Front panel can be used to separate the front and main parts. Equipped with left and right independent power amplifier input levels.

Model Rating

Type	Master integrated amplifier
Power Amplifier Unit
Effective Output (10 Hz to 20 kHz, channel operation)	150W + 150W (6 Ω) 110W + 110W (8 Ω)
Dynamic Power	320W + 320W (2 Ω) 240W + 240W (4 Ω) 190W + 190W (6 Ω)
Total harmonic distortion factor (10 Hz to 20 kHz at effective output)	0.008% (8 Ω)
Intermodulation Distortion Factor (60 Hz : 7 kHz = 4 : 1, SMPTE)	0.008% (8 Ω)
Damping factor	200 (8 Ω)
Frequency Response (1W)	DC ~ 300 kHz (+ 0 dB, -3dB)
Input Sensitivity / Input Impedance (1 kHz)	1 V (5k Ω)
Signal-to-noise ratio (A network)	115 dB or more
Envelope distortion	Measurement limit value or less
TIM (SAWTOOTH)	Measurement limit value or less
Slew rate	± 150 v / μ sec (8 Ω)
Rise time	0.5 μ sec
Headphone out	400 mW (33 Ω)
Load impedance	4 ~ 16 Ω
Preamplifier Section
Input Sensitivity / Input Impedance (1 kHz)	Phono MM : 2.0mV/47k Ω Tuner, CD, Tape Play 1, 2, 3, Line1, 2 : 150mV/47k Ω
Maximum allowable input	Phono MM:200mV(1kHz)
Output Voltage (1 kHz)	Tape Rec (PIN) : 150mV/47k Ω
Output Impedance (1 kHz)	Tape Rec (PIN) : 600 Ω or more
Signal-to-noise ratio (A network)	Phono MM : 88 dB or more Tuner, CD, Tape Play1, 2, 3, Line1, 2 : 110 dB or higher
Subsonic filter	16 Hz (-3dB, 6dB/oct.)
Presence (Volume-40dB)	+2dB(200Hz)
Audio Muting	-20dB
<Others>
Rated power consumption (Electrical Appliance and Material Control Law)	350W
External dimensions	Width 470x Height 178x Depth 486 mm
Weight	35.1kg