Audio Database

The

SANSUI TU-7700
65,000yen(around the 1975 time)

Description
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The FM/AM tuner developed aiming at reappearance of a high-definition tone quality while investigating the basic performances, such as a sensitivity and selectivity, as an FM tuner.

Low noise dual gate MOS type FET was used for RF stage at FM front end, and the high sensitivity has been obtained by having combined with the precision frequency linear-line type 4-unit variable condenser.
Moreover, in order to raise the stonewalling exclusion property used as causes, such as a radio interference, the double tuning circuitry is constituted.
Furthermore, the reception which carried the antenna attenuator switchpoint which can receive on the optimal input level according to the level of a powerful radio wave or a weak radio wave, coped with various radio-wave statuses and felt easy about them is possible.

Two steps of differential amplifications according the newly developed phase linear ceramics filter (four elements) to two pieces and a pair transistor, three customer specific ICs, etc. are used for the FM IF section.
Moreover, the linearity was good for the discriminator, the ratio detection circuitry of the wide band was adopted, and properties, such as an SN ratio, a capture ratio, and AM suppression, are improved.

The phase linear ceramics filter is adopted as the filter element which influences the selectivity of the IF section.

Secular change and a failure of the property by ambient temperature adopted little hi-reliability customer specific IC as the FM MPX section, and the high separation has been obtained.

In AM tuner part, a high-sensitivity ferrite type bar antenna is begun, and it has become the circuitry which was substantial much more by adoption of two customer specific ICs, a ceramics filter, etc. at it.

FM muting circuit serves as a discriminator detection type which adopted hi-reliability IC.
It is a circuit system out of which sound does not come apart from signal level until it detects gap with a tuning frequency and becomes below a fixed distortion.

By preparing a multipath detector other than the multipath observation termination for oscilloscopes, and changing a meter selector shows the orientation of a radio wave best in signal meter.

The noise cancellar switchpoint is carried and an SN ratio is raised at the time of FM stereo reception of a weak-electric-current community, without spoiling musicality.

The power-source part has adopted the good power transformer of a regulation. Moreover, the stabilizing supply by a voltage stabilizer is supplied to the whole-block stage.

FM antenna input terminal can use both a balance type and an unbalance type coaxial termination.

The 2m scheme of signal meter and a tuning meter is adopted.

The output-terminal has adopted two circuitries the object for amplifier, and for a sound recording.
Moreover, level adjustment is possible for the output-terminal for amplifier.

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

The side panel made from die casting is adopted.

4ch adapter corresponding to an FM4ch discrete broadcast was carried.

Rear
Internal MPX
Power-source
Phase
Fizz linear -
Ceramics filter

Rating of a mode
Form FM/AM tuner
<FM tuner part>
Sensitivity (IHF) 1.8 microvolts
THD mono: 0.2% or less
stereo: 0.3% or less
SN ratio 75dB or more
Selectivity 80dB or more
Capture ratio (IHF) 1.5dB
Image frequency rejection 75dB or more (83MHz)
IF rejection 90dB or more (83MHz)
Spurious response rejection 80dB or more (83MHz)
Stereo separation 40dB or more (1kHz)
Frequency characteristic 20Hz - 15kHz
Antenna input impedance 300ohms (balance type)
75ohms (unbalance type)
<AM tuner part>
Sensitivity (bar antenna) 50dB/m(1MHz)
Selectivity 30dB or more (1MHz}10kHz)
Image frequency rejection 80dB or more (1MHz)
IF rejection 80dB or more (1MHz)
<Synthesis>
Output voltage 0V-0.775V (FM100%mod. variable)
Sound-recording Output voltage 0.4V
Power dissipation 9W
Dimensions Width 434x height 130x depth of 243mm
Weight 6.9kg