Audio Database

The

SANSUI AU-7700
99,800yen(around the 1975 time)

Description
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The Integrated Amplifier which made full use of the experience and the technology in a high-class component, and was completed.

Including a Phono circuitry, the structure of the panel on the back attached input terminals upward, and has linked it directly by the substrate and the shortest distance of an equalizer amplifier.
The necessity that this uses the shielding wire constituting the cause of a failure of a high region property was lost, an SN ratio is high and the high region property has realized the good tone quality.

It has the printed circuit board of control amplifier, and rotary switches, lever switches and the unification structure where various volumes were attached directly as for picking.
This prevents a malfunction of a faulty connection etc. and the robustness is improved.

In connection with the chassis less structure, the Tip-of-the-Day grounding is carried out and the electric-current cross interferencee is suppressed.

Power amplifier consists of a three-step drive stage of a Darlington connection which had a differential-amplification circuitry in the first rank, and a power stage by a parallel push pull scheme.
A parallel push pull scheme is the power transistor to which the property was equal per channel,Combining four pieces, the linearity of a current characteristic is good, and the phase response was excellent, big negative feedback was applied over the wide band, and the whole page hardwired-connection pure complementary circuit has acquired the flat frequency characteristic.

The equalizer circuitry has adopted the equalizer circuitry of 4 stone stream compositions which have a differential-amplification circuitry in a first rank input.
The dynamic range excellent in selecting carefully and using an element is realized.

In addition to Bass and Treble, the triple tone control which can also adjust Midrange is carried.
The stream composition of tone amplifier is considered as 6 stone stream compositions which have a differential-amplification circuitry in the first rank, is selecting carefully and using the low-noise type transistor and highly precise CR element, and also has adopted the detent type volume with little error.

The tone multiple contact switch which Bass of a tone control, descent of Treble, and an elevation frequency can choose as three points is carried.

The high filter which adopted the active filter only for NF type with a sufficient property is adopted.
A damping characteristics can be chosen from two kinds, and by a defeet position, it becomes unrelated to a filter circuit and becomes a flat property.
Moreover, the low filter of two-step switching is also carried.

Since the potential of the input/output circuitry of the stage of each block is about 0v potential, it has prevented the it1 noise generated at the time of a multiple-contact-switch switchover.

At the time of a defeet, the perfect defeet scheme which bypasses a tone circuitry and a filter circuit is adopted.
At the time of this defeet, it becomes a whole page}2 power-source operation.

The heavy weight class power transformer and the large capacity power supply capacitor of 10,000 micro Fx2 are adopted as a power-source part, and }2 power source with a regulation strong to the load variations at the time of the Dainyuu power etc. and sufficient is supplied.
Moreover, the power stage and }2 power supply stabilizing circuit by the coil of another system perform a powering in an equalizer circuitry and a tone circuitry, and the influence of the power stage is suppressed.

The high-sensitivity relay was combined with the electronic circuitry, and also the protection network which uses an immediate judgment fuse is adopted.

This detection circuitry that operates a circuitry mostly is the temperature perception circuitry of a power transistor, a transistor safety area detection (ASO) circuitry, an overcurrent detection circuitry, an abnormal-voltage detection circuitry of a speaker protection, and a quadruplicate.

The loudness switchpoint of two-step switching is carried. The usual low high region boost and two-step switching of only a low-pass Booth are possible.

- A fine tune of music level is also possible at a damping of 15dB and -30dB.

Stereo Normal / reverse / monophonic mode changeover switch is carried.

Two tapes monitor circuitries are carried and the sound recording of the special-NetWare-program source and the monitor under sound recording can also be performed.
Moreover, a tape copy is also possible.

The pre-main isolation switchpoint is carried, a preamplifier part and a main-amplifier part are separated, and it can be used independently.

According to a cartridge, a load impedance is changed to the inside of a Phono input circuit by three steps, 30kohms, 50kohm, and 100kohm, Phono1.

2 sets of speaker systems, A and B, can be sounded with a switching of a switchpoint independently and simultaneous.

The large-sized grounding terminal and the standby AC plug socket are carried.

The side panel made from die casting is adopted.

the good aluminum of a feel -- the pure thing metal thumb is adopted.

Internal
A
Tone
Relay Rear

Rating of a mode
Form Integrated Amplifier
Effective output
Both channel operation 20Hz-20kHz:52W+52W (8ohm)
1kHz: 55W+55W (8ohm)
One-side-channel operation 1kHz:58W/58W (8ohm)
Music power 250W (4 ohms, 1kHz)
THD Pre Amp: 0.1% or less
Main Amp: 0.1% or less
Over All: 0.1% or less
Cross modulation distortion
(70Hz:7kHz=4:1, SMPTE)
Pre Amp: 0.1% or less
Main Amp: 0.1% or less
Over All: 0.15% or less
Power Band Width (IHF) 5Hz - 40kHz
Frequency characteristic (at the time of 1W output) 10Hz-50kHz+0.5 -1 dB
RIAA deflection (30Hz - 15kHz) }0.5dB
Dumping factor 30 (8ohm)
Input sensitivity/impedance Phono1:2.5mV/30kohm, 50kohm, 100kohm
Phono2:2.5mV/50kohm
Tuner, AUX, Tape Monitor(Pin/Din):100mV /, 50kohm
Main Amp: 800mV / 50kohm
Phono maximum permissible input (less than THD 0.2%) 300mV
Output voltage (1kHz) Tape Rec(Pin/Din):100mV/30mV
Pre Amp:800mV
channel separation (1kHz) Phono: 50dB or more
Tuner/AUX, Tape Monitor: 55dB or more
Main Amp: 60dB or more
A hum and a noise (IHF) Phono: 75dB or more
Tuner, AUX: 85dB or more
Main Amp: 100dB or more
Tone control Bass: }13dB (50Hz)
Midrange: }5dB (1kHz)
Treble: }13dB (15kHz)
Tone selector Bass:150Hz/300Hz/600Hz
Treble:2kHz/4kHz/8kHz
loudness (Volume-30dB o'clock) High & Low: +10dB (50Hz), +8dB (10kHz)
Low:+10dB(50Hz)
A low filter 20Hz=-3dB(12dB/oct)
60Hz=-3dB(12dB/oct)
A high filter 7kHz=-3dB(6dB/oct)
12kHz=-3dB(12dB/oct
Muting - 15dB-30dB
Power dissipation 120W
Dimensions Width 434x height 130x depth of 315mm
Weight 12.3kg