Description

The AU-9900 is identical to the superb specifications of the AU-11000, except for a slightly reduced power output.

The characteristics included:

Stabilized and well-regulated energy source; oversized power capacitors, advanced toroidal transformer, excellent RIAA equalization.

All the controls, connections and convenience for professional and semi-professional use.

The AU-9900 is one of the largest and most advanced stereo integrated pre/power amplifiers ever introduced in Sansui's popular AU series, created to deliver Sansui's renowned tonal quality to the high power output levels demanded by today's true audiophiles.

Parallel push-pull power output section
The power amplifier section of this robust stereo component features a differential amplifier and a 3-stage Darlington system designed in a parallel push-pull format. The results include a continuous power output of 80 watts, minimum RMS, per channel, both channels driven into 8 ohms, across a bandwidth of 20 Hz to 20 kHz with no more than 0,08% total harmonic distortion.

Stabilized and well-regulated power source
The power supply is one of the most stable and reliable ever developed, providing symmetrical plus-minus voltages to all circuits as needed. Oversized power capacitors contribute to greater stability, while the use of an advanced toroidal transformer also ensures improved power regulation and exceptionally low induced hum.

Excellent RIAA Equalization
The phono equalizer consists of two amplifier sections, each with a differential amplifier. High-frequency attenuation is performed by the CR circuit, while low-frequency inversion is performed by the NF circuit, with maximum precision and very low distortion.

Effective triple tone control
Sansui's popular Triple Tone Control circuit is featured in the AU-9900 to provide the finest and most flexible tone control ever developed. Twelve transistors are used in the circuit, which is itself built around a head stage that uses a differential amplifier. The individual controlsdualThe bass, midrange and treble controls are made even more convenient by the selectable bass (600 Hz, 300 Hz or 150 Hz) and treble (8 kHz, 4 kHz or 2 kHz) turnover switches.

Quadruple protection circuits
Changes in temperature, supply voltage, or short circuits in speaker cables or terminals are detected immediately and cannot cause damage to the connected power transistors or speakers thanks to the use of four separate protection circuits. These are: [1] a temperature detection circuit, [2] a DC voltage detection circuit, [3] an ASO (Safe Operation Area) circuit, and [4] an overload detection circuit.

Tone mute switch
Like the AU-20000 and AU-11000, this integrated amplifier offers the convenience of being able to instantly cancel all tone control adjustments with a tone-off switch.
Two-level low/high filters
The low filter has positions for 12 dB/oct. attenuation at 20 Hz or 60 Hz; the high filter is selectable for 6 dB/oct. cut-off at 7 kHz or 12 dB/oct. cutout at 12 kHz

Other valuable features
The AU-9900 offers all the conveniences necessary for professional and semi-professional use, including a manually adjusted precision volume control, input/output terminals for up to two stereo decks, with full monitoring and deck-to-deck dubbing, a quick-access tuner switch, a modality, the level selector (0 dB/ -10 dB/ -20 dB) and the mute switch.

Output Power: 80 watts per channel into 8Ω (stereo)

Frequency Response: 10Hz to 50kHz

Total harmonic distortion: 0,08%

Damping factor: 80

Input sensitivity: 2 mV (MM), 130 mV (DIN), 130 mV (line)

Signal-to-noise ratio: 65 dB (MM), 80 dB (line)

Channel separation: 55 dB (MM), 60 dB (line)

Output: 130mV (line), 30mV (DIN), 0,7V (pre out)

Speaker load impedance: 4Ω to 8Ω

Size: x 460 160 373 mm x

Weight: 17,9 kg

Year: 1975

Specifications

Amplification type	transistor
RMS power per channel	80 W
Reference load	8 ohm
Stadio phono	MM
Analog inputs	Phono MM, DIN, line
Harmonic Distortion (THD)	0.08%
Frequency response	10Hz to 50kHz
Rapporto S/N	80 dB
Line input sensitivity	130 mV
Input impedance	2 kOhm
Dimensions (WxHxD)	460 x 160 x 373 mm
Weight	17.9 kg
Year of production	1975
country of origin	Japan

About the brand

Sansui is one of the most beloved names in Japanese hi-fi. The era that enthusiasts remember spans the 1960s to the 1990s, when the company designed and built amplifiers, tuners, and turntables in Japan that influenced generations of listeners.

Sansui: what brand is it?

Sansui Electric was founded in Tokyo on June 3, 1947, by Kosaku Kikuchi. Initially, it produced transformers. From 1954, it switched to tube amplifiers and preamplifiers, and in 1958, it introduced its first tube stereo preamplifiers and power amplifiers. In the 1970s, it also made a name for itself with quadraphonic audio, with the QS-1 synthesizer in 1971 and the QS Vario Matrix decoder in 1973. During that period, its product line included amplifiers, tuners, receivers, turntables, cassette decks, and reel-to-reel tape recorders.

Then the market changed. The Shin-Yokohama plant closed in 2001, and in the early 2000s, high-end amplifier production in Japan ended. The Japanese company then ceased production in 2014. Since then, the Sansui name has also appeared on products made under license by other companies, which share only the brand name with the historic models.

AU Series Integrated Amplifiers

The AU series is at the heart of Sansui's history. The matte black front panel, typical of these integrated amplifiers, dates back to the mid-1960s. Among the models that many remember is the AU-999 from 1970, a solid-state integrated amplifier without output capacitors. The most famous is perhaps the AU-9500, introduced in October 1972 as the flagship: approximately 75-80 watts per channel and weighing over 20 kg.

Diamond Differential, X-Balanced, and the arrival of digital

In the late 1970s, Sansui introduced the "Diamond Differential" circuit in the power stage, for example in the AU-D607. In 1984, the AU-D907X introduced "X-Balanced" technology, which uses a balanced drive to reduce the effects of mass on the sound. The evolution of these circuits continued in the following years up to the Alpha series models, which remained in the catalog until 2000.

At the end of the 1980s came the AU-X911DG, with a built-in D/A converter for directly connecting a CD player: a sign of how the brand was trying to accompany traditional integrated amplifiers towards new digital sources.

What makes a Sansui recognizable?

The first feature is aesthetic. The matte black front of the AU integrateds has distinguished Sansui from the often silver-plated units of other Japanese manufacturers for decades, and even today, a glance is enough to recognize them.

The second is technical. Throughout its history, Sansui has worked primarily on the power stage: from the capacitor-free output of the AU-999 to the Diamond Differential and X-Balanced circuits, the goal has always been to reduce what comes between the signal and the speakers.

The third is the completeness of the offering. In the golden years, it was possible to build an entire Sansui system, from turntable to tuner to amplification, with a coordinated aesthetic. For those new to the brand today, it's useful to distinguish between the historic models, designed by Sansui Electric, and the more recent products that bear the same name under license.

Information and advice

Audiocostruzioni It is a shop with showroom and listening room in Carpi and an online store on audiocostruzioni.com. For information on Sansui models or for a system consultation, you can email us or stop by the store: in our listening room, we'll help you choose speakers and sources that match your electronics.

Explore Sansui