What is stereo?




There are now two system of high fidelity, monophonic (monaural) and stereophonic. Monophonic is a system that starts from one microphone and is fed through a single high fidelity set. Stereophonic is a double system. Two separate microphones are placed at different sides of the orchestra and two different systems are used to keep the two signals or channels separated. Two separate speakers are used, placed on different sides of you room. Stereo is much like 3-D photography, two slightly different sound reach your ears giving you a new dimension in sound.




H.H. Scott '59





Sansui AU-9900


The AU-9900 is one of the largest and most advanced of any integrated stereo pre/power amplifiers yet introduced in the popular Sansui AU Series, instruments created to deliver the famed Sansui tonal quality al. 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 diferential amplifier and a 3-stage Darlington system designed in the parallel push-pull format. The results include a continuous power output of 80 watts, min. RMS, per channel, both channels driven into 8 ohms, over a 20 Hz to 20 kHz bandwidth with no more than 0,08% total harmonic distortion.

Stablized, Well-Regulated Power Source
The power supply section is one of the most stable and dependable ever developed, providing plus-minus symmetrical voltages to all circuits as needed. Oversized power capacitors help provide extra stability, while the use of an advanced toroidal transformer further assures better power regulation and exceptionally low induced hum.

Excellent R.I.A.A. Equalization
The phono equalizer consists of two amplifying sections each with a differential amplifier. High frequency roll-off  is made by the CR type circuit and low frequency turn-over is made by the NF type circuit, most accurately and with very low distortion.

Effective Triple Tone Control
Sansui's popular Triple Tone Control circuit is featured in the AU-9900 to provide the best, most flexible tonal adjustment control yet developed. Twelve  trans istors are used in the circuit, itself built around an initial stage using, a differential amplifier. The individual controls for Bass, Midrange and Treble are made still more convenient by the selectable turnover switches for Bass (600 Hz, 300 Hz or 150 Hz) and Treble (8 kHz, 4 kHz or 2 kHz).

Quadruple Protection Circuits
Changes in temperature, line voltage supply or shorts in speaker leads or terminals are instantly detected and can cause no damage to the power transistors or connected speakers thanks to the use of four separate protection circuits. These are: [1] a temperature sensing circuit, [2] a DC voltege detection circuit, [3] an ASO (Area of Safety Operation) circuit, and [4] an overload detection circuit.

Tone Defeat Switch
Like the AU-20000 and AU-11000, this integrated amplifier provides the convenience of being able to cancel all tone control adjustments instantly with a Tone Defeat Switch
Two-Stepped 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. cut-off at 12 kHz

Other Valuable Features
Teh AU-9900 provides every convenience needed for professional and semi-professional use, included are a hand-trimmed precision volume comtrol, input/output terminals for up to two stereo decks, with full monitoring and deck-to-deckdubbing, a quick-access Tuner Switch, Mode Switch, Level Selector (0 dB/ -10 dB/ -20 dB) and an Audio Muting Switch.

Specifications
Power Output (min. RMS, both ch. driven, 20-20,000 Hz, no more than 0,05% T.H.D.):
80 watts per channel into 4 and 8 ohms
Load Impedance: 4 and 8 ohms
Power Bandwidth:  20 - 20,000 Hz (at or below rated min. RMS power output and T.H.D.)
Total Harmonic Distortion (overall from AUX): less than 0,05% (at or below rated min. RMS power output and T.H.D.)
Intermodulation Distortion (70 Hz : 7 kHz = 4:1 SMPTE method):
Overall (from AUX) less than 0,05%
Frequency Response (at 1 watt):
Overall (AUX to power output) 10 to 50,000 Hz +0 dB, -1 dB
RIAA Curve Deviation (Phono):  +0,3 dB, -0,3 dB (30 to 15,000 Hz)
Channel Separation (at rated output 1,000 Hz):
Phono 1 and 2 :  better than 55 dB
Tuner :  better than 60 dB
Aux 1 and 2 :  better than 60 dB
Power Amplifier:  better than 70 dB
Tape Monitor :  better than 60 dB
Hum and Noise (IHF):
Phono 1 and 2 :  better than 65 dB
Tuner :  better than 80 dB
Aux 1 and 2 :  better than 80 dB
Power Amplifier:  better than 100 dB
Tape Monitor :  better than 80 dB
Input Sensitivity/Impedance:
Phono 1 :  2 mV, 4 mV, 8 mV / 30 k, 50 k, 100 k Ω
Phono 2 :  2 mV/ 50 k Ω
Max.input Capability:  more than 300 mV rms 0,1% distortion
Tuner :  130 mV /50 k Ω
Aux 1 and 2 :  130 mV / 50 k Ω
Tape Pb  1 and 2 :  130 mV (PIN)
Tape Pb 2 :  130 mV (DIN)
Recording Output:
Tape 1 :  130 mV (PIN)
Tape 2 :  130 mV (PIN); 30 mV (DIN)
Controls:
Bass :  +10 dB; -10 dB at 30 Hz
Midrange :  +5 dB, -5 dB at 1,500 Hz
Treble:  +10 dB, -10 dB at 20 kHz
Tone Selectors:
Bass :  150 Hz, 300 Hz, 600 Hz
Treble:  2 kHz, 4 kHz, 8 kHz
Filters:
Low :  -3 dB at 20 Hz (12 dB/oct); -3 dB at 60 Hz (12 dB/oct)
High :  -3 dB at 7 kHz (6 dB/oct); -3 dB at 12 kHz (12 dB/oct)
Muting:  0 dB; -20 dB
Level Set: 0 dB; -10 dB; -20 dB
Power Requirements
Voltage :  100; 120; 220; 240 V , 50/60 Hz
Consumption:  180 watts Rated
Dimensions ((W x H x D):  460 x 160 x 375 mm (18-1/8" x 6-5/16" x 14-49/64")
Weight [net/packed]:  18 kg (39,7 lbs)/ 20,3 kg (44,8 lbs)

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