Sansui - Au-X 1 - 100v Solid state integrated amplifier

An amplifier designed to pursue the ideal that "an amplifier must be a single conductor with an amplification degree that faithfully transmits music signals" as far as possible.
It is a 2-transformer system consisting of a 600 VA large-capacity toroidal transformer and an 80 VI ・ EI transformer. Custom large-capacity electrolytic capacitor 10,000 μ Fx8 developed exclusively for audio is connected in parallel. A 1.2 mm thick copper plate is used in the ground circuit. Therefore, even if the speaker impedance changes with frequency, stable operation is achieved by the powerful power supply.
The head amplifier section is a DC amplifier configuration that further advances symmetrical push-pull input / output using newly developed low-noise, high-gmP-ch and N-ch FET. The first stage is a direct-coupled push-pull input in which a large number of low-noise, high-gmP-ch and N-ch FETs are connected in parallel, realizing ideal input impedance and high S/N ratio.
The second stage is an MC amplifier circuit with excellent linearity and excellent open-loop characteristics due to a push-pull drive double-stage direct connection circuit using a combination of NPN-PNP transistors.
In addition, extremely stable operation is obtained by supplying power exclusively for MC and independently for the left and right.

The equalizer amplifier section consists of a direct-coupled DC amplifier with a diamond differential circuit. The first stage has good pair characteristics, low-noise, high-gm, differential input circuit using dual FET, and cascode bootstrap circuit which is not affected by input impedance.
In addition, the high-performance constant current circuit (PAT. PEND) composed of a 2-stage direct-coupled circuit composed of NPN-PNP transistor combination provides high CMRR (in-phase component suppression cost) at the summing point and excellent dynamic characteristics. The second and third stages are diamond differential circuit + current differential push-pull with excellent drive capability, and the output stage is SEPP circuit with Darlington connection, which has sufficient current margin. The low-output impedance and low-impedance NF circuit design provides sufficient dynamic range even against changes in load impedance, and S/N ratio is improved.

The flat amplifier adopts a push-pull drive DC amplifier configuration with a differential input circuit using newly developed 1 Tip (4 elements enclosed) FET in the first stage, and achieves excellent operation by independent power supply on the left and right.

Type Stereo pre-main amplifier
Power Amplifier Unit
Effective output (5 hz to 20 khz, THD 0.007%) 160W + 160W (8 Ω)
220W + 220W (4 Ω)
Effective output (1 kHz, THD 0.003%) 160W + 160W (8 Ω)
220W + 220W (4 Ω)
Total harmonic distortion factor (5 Hz to 20 kHz) 0.007% or Less (8 Ω)
0.008% or Less (4 Ω)
Intermodulation distortion factor (70 hz : 7 khz = 4 : 1) 0.007% or Less (8 Ω)
0.008% or Less (4 Ω)
Output Bandwidth (IHF, THD 0.02%) 5 Hz ~ 70 kHz (8 Ω)
Frequency Response (1W) DC ~ 500 kHz (+ 0 dB, -3dB)
Input Sensitivity / Impedance (1 kHz) 1V/33k Ω
S/N ratio (IHF, A-network) 125 dB or more


For sale: an amplifier refurbished by a professional last month.
The output stages have been repair calibrated; the power supply and preamplifier have been overhauled, with contact issues and noisy transistors replaced or repaired.
Equipped with high-quality audio-grade capacitors.
Shipped in foam packaging.
Weighs 28 kg; delivers massive power (2x160 W)8 ohm
AC 100 V!max Power 900 W !
use to converter
Sounds beautiful.
A Sansui flagship model.
Condition as shown in the photos: there are a few scratches, but overall it is in good condition.