This newly restored Sansui AU-9900 is a flagship integrated amplifier from Sansui’s golden era, delivering 80W per channel of pure, dynamic power. Built with a true dual-mono layout and advanced OCL circuitry, it offers exceptional clarity, detail, and musical warmth. Its precision 3-band tone controls, selectable turnover frequencies, and low/high filters give you total control over your sound.
Crafted for both versatility and sonic purity, the AU-9900’s preamp and power amp sections can be separated, making it a perfect match for various system configurations. Solidly built at 17.6kg, it embodies Sansui’s hallmark engineering and timeless design—a true collector’s piece for those seeking vintage Japanese HiFi excellence.
This vintage Sansui AU-9900 has been meticulously cleaned and fully restored inside and out by our Takumi (master craftsmen). Following a complete overhaul, it is now ready to be the masterpiece of your HiFi system.
Sansui AU-9900
The Sansui AU-9900 represents the peak of Sansui’s mid-70s integrated amplifier engineering, combining meticulous circuit design with robust mechanical construction. Every element was built with the dual goals of sonic purity and long-term reliability.
Chassis & Layout
- True Dual-Mono Construction – Left and right channels are electrically and physically separated from the transformer stage onwards. This dramatically reduces crosstalk and improves stereo imaging.
- Rigid Steel Frame – Heavy-gauge steel chassis with reinforced frame to eliminate vibration-induced noise.
- Logical Internal Layout – Signal path is kept short, with inputs and controls arranged for optimal flow and minimal interference.
- Side-Mounted Speaker Terminals – Designed for cleaner rear cable management and better separation from AC mains wiring.
Amplification & Circuitry
- OCL (Output Capacitor-Less) Design – Delivers tighter bass, greater damping factor, and more natural transient response.
- Differential Amplifier Input Stage – Improves linearity and reduces noise floor for high-resolution signal reproduction.
- Parallel Push-Pull Output Stage – Uses matched transistor pairs to provide stable high-current delivery under complex loads.
- High-Grade Components – Precision resistors, low-noise transistors, and Sansui-spec electrolytic capacitors for consistent tonal balance.
Controls & User Interface
- Three-Band Tone Controls – Separate bass, midrange, and treble adjustments with selectable turnover frequencies for precise tonal shaping without excessive phase shift.
- Filter Options – Low (subsonic) and high filters to reduce unwanted rumble and hiss from vinyl and tape sources.
- Loudness Compensation – Maintains perceived tonal balance at low listening volumes.
- Muting & Attenuation – Adjustable muting to quickly drop output levels without powering down.
- Dual Tape Loops – Independent tape monitor circuits for recording and dubbing flexibility.
Connectivity & Flexibility
- Separable Preamp & Power Amp Sections – External processors or upgraded power stages can be added via Pre-Out / Main-In jumpers.
- Multiple Speaker Outputs – Switchable A/B speaker pairs with independent impedance handling.
- Phono Stage – Precision MM phono preamp with high overload margin, designed for low-noise vinyl playback.
- Multiple Line Inputs – Supports tuner, auxiliary, and two tape decks for system versatility.
Build Quality & Serviceability
- Oversized Power Supply – Large EI-core transformer and dual filter capacitors for stable power under demanding loads.
- Robust Heat Dissipation – Large aluminium heat sinks ensure safe operation over extended sessions.
- Service-Friendly Design – Modular internal boards for easier access during maintenance and restoration.