Pioneer SX-717
¥ 78,000 (released in 1972)
Commentary
A stereo receiver that employs a pure complimentary service OCL circuit directly connected to all stages.
The power amplifier section employs a pure complimentary service OCL circuit directly connected to all stages. This circuit extends linearly to the ultra-low frequency range, which has been interrupted by the reactances of the output capacitor. The very small inductance of the capacitor does not adversely affect the characteristics of the ultra-high frequency range. Moreover, there are no unstable elements such as oscillation caused by the coupling capacitor, so NF is sufficiently applied.
As a result, the low-frequency and high-frequency characteristics are improved and a low distortion factor is achieved over the entire band.
Pioneer uses its own protection circuit that combines 8-transistor, 10-diode, and relay.
In the event of a trouble such as a loss of DC balance at the output stage or an overload such as short-circuiting of the speaker terminals, the electronic circuit detection section immediately catches the trouble and activates the relay to protect the speakers and power transistors.
This protection circuit also functions as a power muting to suppress the noise caused by the rush current when the power is turned on.
Since it is an automatic recovery type protection circuit, it automatically returns to the operating state when the trouble is solved.
It employs a front end of a high-frequency two stage amplifier circuit that combines a four link varicon and FET.
The IF section combines an IC and a ceramic filter to obtain sharp selectivity characteristics.
It is designed with an emphasis on the Hi-fi reception of the AM tuner. It employs a forward AGC circuit to suppress distortion at strong input, and a ceramic filter is used for the IF section.
A wide dial scale is mounted on the panel surface, and a two meter system of signal strength meter and center tuning is adopted.
FET is used in the FM muting circuit to eliminate unpleasant inter-station noise during FM channel selection.
The FET gate is controlled by a narrow pulse near the tuning point center by stiffening the muting voltage from the S-curve and IF stage.
The tone control amplifier uses a 3-stage direct-coupled NF type circuit that uses FET at the first stage. Since the input impedance is high, the S/N ratio does not decrease depending on the volume level and stable characteristics are obtained.
The knob is a double type and both Bass and Treble can be controlled independently on the left and right.
In addition, since it is a Klix/Klukš top type, it is possible to reproduce characteristics according to the listening room.
It is equipped with an audio muting switch that attenuates the volume by 20 dB with the switch ON.
The preamp and power amp sections can be separated by plugging the rear panel.
You can configure a multi-amplifier system simply by adding an electronic crossover network and a power amplifier.
Equipped with a low filter and a high filter that effectively cut out noise such as motor ground noise and scratch noise.
Model Rating
Type | FM/AM stereo receiver | ||||||
FM Tuner Section | |||||||
Practical sensitivity (IHF) | 1.8 μ V | ||||||
Capture Ratio (IHF) | 2.0dB | ||||||
Effective selectivity (IHF) | 70 dB or more | ||||||
S/N | 70dB | ||||||
Image Interference Ratio (82 MHz) | 90 dB or more | ||||||
IF Interference Ratio (78 MHz) | 100 dB or more | ||||||
Spurious interference ratio (82 MHz) | 90 dB or more | ||||||
AM suppression ratio | 50dB | ||||||
Harmonic distortion factor (100% modulation) | Mono : 0.3% or less Stereo : not more than 0.5% |
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Stereo separation (1kHz) |
40 dB or more | ||||||
Residual carrier level | 50 dB or more | ||||||
Antenna | 300 ohm balanced 75 Ω Unbalanced Type |
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Muting | ON-OFF enabled | ||||||
<AM Tuner Section> | |||||||
Practical sensitivity (IHF) | 10 μ V | ||||||
Selectivity (1 MHz) | 35 dB or more | ||||||
S/N (30% modulation) | 50 dB or more | ||||||
Image Interference Ratio (1 MHz) | 80 dB or more | ||||||
IF interference ratio | 75 dB or more | ||||||
Antenna | Ferrite bar antenna | ||||||
Power Amplifier Unit | |||||||
Music Power (IHF) | 195W (4 Ω) 122W (8 Ω) |
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Effective power |
|
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Harmonic distortion factor | 0.5% or Less (Effective Output) | ||||||
Cross modulation distortion factor | 0.5% or Less (Effective Output) | ||||||
Output Bandwidth (IHF) | 10 Hz to 60000 Hz | ||||||
Frequency characteristic | 7 Hz to 80000 Hz ± 1 dB | ||||||
Input Sensitivity / Impedance (1 kHz at effective output) |
500mV/50k Ω | ||||||
Load impedance | 4 Ω ~ 16 Ω | ||||||
Damping factor | 40 or More (8 Ω, 1 kHz) | ||||||
Preamplifier Section | |||||||
Output level | Effective output : 500 mv Maximum : 4 v |
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Harmonic distortion factor | Not more than 0.1% | ||||||
Frequency characteristic | 10 Hz to 20000 Hz ± 1 dB | ||||||
Input Sensitivity / Impedance (1 kHz at effective output) |
Phono1, 2 : 3mV/50k Ω MIC : 2.7mV/50k Ω AUX, Tape Mon1, 2 : 200mV/100k Ω |
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Recorded output | Tape Rec1, 2 (pin jack) : 200 mv DIN connector : 35 mv |
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Tone control | Bass and Treble | ||||||
Low Filter | -8dB at 50 Hz, 6dB/oct. | ||||||
High Filter | -9dB at 10 kHz, 9dB/oct. | ||||||
Equalizer | RIAA S.T.D | ||||||
Loudness (at volume -40dB) |
100Hz:+10dB 10kHz:+6dB |
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Muting | -20dB | ||||||
Hum and noise (IHF) | Phono : 85 dB or more AUX : 95 dB or more |
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<General> | |||||||
Rated power consumption | 100W | ||||||
Maximum Power Consumption | 270W | ||||||
External dimensions | Width 485x Height 150x Depth 390 mm | ||||||
Weight | 14kg |