Sansui AU-X1111MOS VINTAGE

Flagship integrated amplifier from Sansui's AU-X series, with twin monaural construction and a fully balanced, ground-free design

Overview

The Sansui AU-X1111MOS VINTAGE is the last model in the AU-X amplifier series and the top of Sansui's high-end analog line. It is a master integrated amplifier with fully independent preamp and power amp sections. You can separate them with front panel controls. The circuit is a balanced, ground-free "Earth-based" design. Both speaker terminals are actively driven in a double push-pull configuration, and a closed-loop, ground-free power supply backs it up.

Specifications

Year of Production	Not specified
Effective Output (8 Ω)	110W + 110W (10 Hz – 20 kHz, both channels driven)
Dynamic Power (2 Ω)	320W + 320W
Total Harmonic Distortion	0.008% (10 Hz – 20 kHz, 8 Ω, rated output)
Damping Factor	200 (8 Ω)
Frequency Response (Power Amp)	DC – 300 kHz (+0 dB, -3dB, 1W)
Slew Rate	±150 V/μsec (8 Ω)
Signal-to-Noise Ratio (A-weighted)	115 dB or more
Input Sensitivity / Impedance (Main In)	1 V / 5k Ω
Phono MM Input Sensitivity / Impedance	2.0 mV / 47k Ω
Line Input Sensitivity / Impedance	150 mV / 47k Ω
Headphone Output	400 mW (33 Ω)
Load Impedance	4 – 16 Ω
Dimensions (W × H × D)	470 × 178 × 486 mm
Weight	35.1 kg
Rated Power Consumption	350 W
Original Price	¥400,000 (around 1988)

Design

The amplifier is twin monaural, with a central heavy-duty power transformer and symmetrically separated amplifier sections on dedicated heatsinks. The output stage uses 16 MOS FETs in a diamond differential configuration - four double push-pull pairs per channel - and the signal path is DC-coupled. The power MOS FETs, the transformer and the master volume control are mounted on a pure copper plate. More copper plating and copper insulators are used throughout the chassis. The power supply is non-switching, with a large transformer, custom high-capacity audio capacitors and fast recovery diodes. Balanced transmission means no line filter is needed. A dedicated video input with internal IC switching runs from its own separate transformer. The cabinet has real rosewood side and top panels, a front glass panel and shower lights. The presence control boosts mid/low frequencies at low volumes without changing the overall tone balance. Left and right channel volume controls are independent.

Context

The AU-X1111MOS VINTAGE is the final model in the Sansui AU-X series, which began with the AU-X1. It ended the line of high-fidelity amplifiers.

Similar items on eBay

No exact Sansui AU X1111 listings are live right now — these searches show current Sansui and similar vintage audio gear on eBay:

Search Sansui AU X1111 on eBay Browse Sansui audio gear on eBay

As an eBay Partner, we earn from qualifying purchases. This helps support our independent vintage technology research.