Technics ST-S5A
¥ 44,800 (released in 1982)
Commentary
A quartz synthesizer tuner that realizes faithful waveform transmission up to the DC range by using a DC circuit configuration.
Equipped with a DC peak sample-and-hold MPX circuit, and combined with the effect of DC, the stereo separation of 60 dB, which is the same as 1 kHz, is obtained even at 20 Hz.
The 19 kHz pilot signal used for stereo demodulation in the MPX circuit is canceled sharply in the electronic circuit. Moreover, an auto-level adjuster is obtained to prevent leakage due to pilot signal fluctuation. This realizes flat and wide-band frequency characteristics.
In addition, a steep LC bandpass filter is used to eliminate jitter distortion caused by the fluctuation of the 38 kHz signal for demodulation to the high-frequency audio signal.
The reference frequency is set to 25 kHz, which is outside the range of audibility range, to prevent adverse effects on the music signal and to improve the SN ratio.
A unique swirl-in counter system is adopted in the synthesizer section.
A special frequency division method in which the 1/16 and 1/17 frequency dividers are controlled by a prescaler controller prevents spurious interference from occurring in the broadcast band and makes waveform transmission more faithful.
A microcomputer automatically switches between a normal position with an effective selectivity of 55 dB at ± 400 kHz detuning and a super narrow IF with an effective selectivity of 25 dB at ± 200 kHz detuning, according to the presence / absence / strength of an interfering signal and the input signal level.
Manual operation is also available for normal / super narrow position switching.
The FM front end consists of a single-double electronic tuning circuit with a high-Q varicap and newly developed 4-pole structure MOS-FET.
The detector stage employs quadrature detection, which has excellent stability over a wide band.
Eight preset memories are available for each FM and AM.
Each of the 8 preset buttons is equipped with an indicator, and the channel selection button can be checked at a glance by lighting the LED.
Each push of the tuning button changes the frequency in 100 kHz steps for FM and 9 kHz steps for AM. You can set the tuning frequency while viewing the frequency on the digital display. If you keep pressing the tuning button, the operation shifts to high-speed up/down operation. If you release your finger, the operation automatically enters auto-scan operation, finds the nearest station, and stops scanning.
It is equipped with an auto memory function that enables you to set a preset by pressing the memory button.
If you press the signal level switch, the FM signal strength is displayed up to approximately 54 dB in 2 dB steps.
It is equipped with a memory backup with a large gold capacitor of 3.3 μ F that does not require batteries, and it compensates for power failure for about one week.
Equipped with a switchless FM wing antenna terminal, it can be directly connected to Technics FM wing antenna (SH-F100) and automatically tuned.
By connecting SH-4060 to the control input terminal, channel switching and time can be set freely.
(When SH-4060 is connected, ch1 to ch8 of SH-4060 correspond to the preset buttons of FM1ch to 8 ch of S5A, and ch9 to ch16 of SH-4060 correspond to the preset buttons of AM1ch to 8 ch of S5A.)
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Model Rating
| Type | Quartz synthesizer FM/AM tuner |
| FM Tuner Section | |
| Receiving frequency | 76.1 mhz to 89.9 mhz |
| Practical Sensitivity (75 Ω) | 10.3dBf/0.9 μ V (IHF' 58) |
| SN50dB Sensitivity (75 Ω) | Mono : 18.1dBf/2.2 μ V (IHF' 58) Stereo : 38.1dBf/22 μ V (IHF' 58) |
| Distortion factor | mono:0.04% stereo:0.06% |
| Signal-to-noise ratio | mono:80dB |
| Frequency characteristic | 5 hz to 18 khz + 0. 2-0. 5 db |
| Effective selectivity | Normal : 55 dB (± 400 kHz) Super narrow : 25 dB (± 200 kHz) |
| Capture ratio | 1.0dB |
| Image interference ratio | 90dB(83MHz) |
| IF interference ratio | 100dB(83MHz) |
| Spurious interference ratio | 105dB(83MHz) |
| AM suppression ratio | 55dB |
| Stereo separation | 50dB(20Hz) 60dB(1kHz) 45dB(10kHz) |
| Leak Carrier (19 khz) | -70dB |
| <AM Tuner Section> | |
| Receiving frequency | 522 kHz to 1611 kHz |
| Practical sensitivity (S/N = 20 dB) | 290 μ V/m, 20 μ V |
| Selectivity | 55dB |
| Image interference ratio | 40dB |
| IF interference ratio | 60dB |
| <General> | |
| Power failure compensation | Approximately 1 week, charging system |
| Pwer | 100 VAC, 50Hz/60Hz |
| Power consumption | 9W |
| External dimensions | Width 430x Height 53x Depth 300 mm |
| Weight | 3.3kg |