Sansui AU-X11 ()
A master integrated DC amplifier built with discrete power supplies and advanced circuitry for high-fidelity stereo reproduction
Overview
The Sansui AU-X11 is a high-end integrated DC amplifier developed to embody the ideal form of integrated amplifier design, incorporating the company's most advanced audio technologies of the early 1980s. Built with an obsessive focus on signal purity and power isolation, it features fully independent left and right power supplies, DC amplifier configurations throughout, and discrete circuit blocks for each critical stage. This model was positioned as a flagship "Master" amplifier, reflecting Sansui’s commitment to technical excellence in analog audio reproduction.
Specifications
| Effective Output (10 Hz – 20 kHz) | 160W + 160W (8 Ω) |
| Total Harmonic Distortion | 0.004% or less (8 Ω, 10 Hz – 20 kHz) |
| Output Bandwidth (IHF) | 5 Hz – 100 kHz (8 Ω, both channels driven) |
| Frequency Response (1W) | DC – 300 kHz (+0, -3 dB) |
| Signal-to-Noise Ratio | Phono MM: 91dB, Phono MC: 77dB, Tuner: 110dB |
| Input Sensitivity / Impedance | Phono MC high: 85 μV/30 Ω, Phono MC low: 270 μV/100 Ω |
| Maximum Allowable Input | MM: 330mV, MC: 40mV |
| RIAA Deviation (MM) | 20 Hz – 20 kHz: ±0.2 dB |
| High Filter | 16 Hz (-3dB, 6dB/octave) |
| Rated Power Consumption | 400W |
| External Dimensions | 515 mm (W) × 197 mm (H) × 450 mm (D) |
| Weight | 28.0 kg |
| Original Price | ¥275,000 (circa 1982) |
Design
The power stage uses Super FF and a diamond differential circuit to minimize distortion and improve transient response. The equalizer amplifier employs low-noise, high-gm dual FETs with a diamond differential configuration and DC servo control for stable, high-fidelity phono playback. The MC head amplifier uses a DC amplifier design with a 14-stone FET single-channel push-pull input/output and separate power supplies for left and right channels. The power supply section includes a large toroidal transformer for the power amplifier stage and a large EI transformer for the voltage amplifier stage, with eight completely independent power supplies for the power stage, pre-drive stage, flat amplifier, equalizer, and MC head amplifier. The chassis is all copper-plated, using flux-free NM elements, copper-plated screws, and a wood bonnet for optimal shielding and mechanical stability.
Context
This master integrated DC amplifier was developed in pursuit of the ideal form of integrated amplifier, incorporating all of Sansui’s advanced sound technologies into a single, high-performance unit.
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