Audio Database

AU-777D
Commentary

This is a pre-main amplifier that has been upgraded by focusing all efforts on the quality of sound itself without changing the circuit structure by adding partial improvement to the AU 777.

The main amplifier section uses a quasi complimentary service Darlington circuit.

All amplifier circuits from the first stage to the final output stage are composed of NF amplifiers to improve frequency characteristics, distortion and S/N, and all stages are composed of silicon transistors.

The preamp section and main amplifier section can be separated and used independently.

Equipped with T. T. C. (Triple Tone Control) which adds Midrange to Bass and Treble.
This allows for more accurate program and acoustic compensation.

A stereo balance check circuit is provided to make it easy to adjust the right and left balance accurately.
By turning the switch down to the test while listening to the monaural signal, you can easily and accurately adjust the balance without any sound if it is balanced properly.

SANSUI's original pure electronic PSC circuit is used to prevent damage to the power transistor even if the output terminal is accidentally short-circuited.
In addition, a power transistor is combined with a short-cut fuse to ensure safety.

It has a center channel output jack and two circuits, a flat output and a 159 Hz high-cut output, so you can enjoy 3 d stereo by connecting a mono amplifier and woofer.

The power transistor is spread over the 3 mm aluminum extrusion back panel to increase the heat radiation effect, so that it can withstand a long performance with a margin.

Equipped with low filter, high filter, loudness, tape monitor circuit, headphone jack, muting switch, etc.

Model Rating
Type Solid state / pre-main amplifier
Main Amplifier Section
Rated output Music Power (IHF) : 70W ± 1 db (8 Ω)
Effective output : 30W/30W ± 1 dB (8 Ω)
Total harmonic distortion factor Not more than 0.5%
Intermodulation distortion factor (60 hz : 7 khz = 4 : 1) Not more than 0.8%
Power Band With (IHF) 20 Hz ~ 50000 Hz (Distortion Factor 0.5%)
Frequency characteristic 20 Hz to 100,000 Hz, ± 1 db
Channel separation 20 dB or More (1000 Hz)
Hum and noise (IHF) 100 dB or more (closed circuit)
Input Sensitivity / Impedance 1V/300k Ω (Rated Output, 1 kHz)
Damping factor 15 (8 Ω)
Load impedance 4 Ω ~ 16 Ω
Center channel output voltage Flat Output : 10 V (1 kHz)
High-Cut Output (fo = 159 Hz) : 10 V (50 Hz)
Preamplifier Section
Output voltage Maximum output voltage : 4 V
Rated output voltage : 1 V
Total harmonic distortion factor 0.1% (Rated Output Voltage)
Frequency characteristic 20 Hz to 70,000 Hz, + 0.5 -1.5 dB
Hum and noise (IHF, maximum output voltage) Phono1, 2 : 80 dB or more (closed circuit)
MIC : 85 dB or more (closed circuit)
Tuner : 85 dB or higher (open circuit)
AUX : 85 dB or more (open circuit)
Input Sensitivity / Impedance
(Rated Output Voltage, 1 kHz)
Phono1 : 2 mV ± 3dB/50k Ω
Phono2 : 2 mV ± 3dB/30k Ω, 50k Ω, 100k Ω
MIC : 3.5 mv ± 3dB/50k Ω
Tuner : 140 mv ± 3dB/100k Ω
AUX : 140 mv ± 3dB/100k Ω
Tape Mon (Pin) : 140 mv ± 3dB/100k Ω
Tape Recorder (Din) : 140 mv ± 3dB/100k Ω
Recorded output Tape Rec (Pin) : 150 mv ± 3 db
Tape Recorder (Din) : 30 mv ± 3 db
Controls Bass : 20 Hz ± 15 dB (in 3 dB steps)
Midrange : 1,500 Hz ± 5 dB (in 1 dB steps)
Treble : 20,000 Hz ± 15 dB (in 3 dB steps)
Loudness (volume -30dB) : 50 Hz + 8 dB, 10,000 Hz + 2.5 dB
SWITCH High Filter : 20,000 Hz, -18dB (12dB/oct.)
Low Filter : 20 Hz, -26dB (12dB/oct.)
Muting : -20dB
<General>
Configuration 31 tr, 5 di
Power supply voltage 100 V, 50Hz/60Hz
External dimensions Width 435x Height 155x Depth 334 mm
Weight 12.5kg
Sold Separately Walnut wood case (¥ 4,150)