Technics ST-8600
¥ 72,800 (released in 1975)
Commentary
FM/AM tuner developed based on ST 9600 with the theme of faithful waveform transmission.
It is equipped with a 19 kHz pilot signal cancellation circuit unique to Technics.
As a result, we have succeeded in extending the frequency response to 18 kHz while suppressing the leak carrier.
In the FM IF circuit, four group delay flat ceramic filters composed of two elements with excellent waveform transmission characteristics are used for the signal system filter to improve the selectivity characteristics and the amplitude characteristics are improved by constructing a 6-stage differential amplification IF amplification system with excellent limiter characteristics.
The IF circuit of the control system uses two narrow-band ceramic filters and a 5-stage amplification factor with AGC, and has obtained excellent characteristics for an electrolytic strength meter which changes into a straight line by input.
A muting circuit is formed by an AND circuit together with a bandwidth control circuit using an independent L / C back-tuned circuit, and input level control is performed in two stages.
A newly developed frequency number line type FM5 series AM3 series variable capacitor is used for the front end part.
In addition to electrical accuracy, it uses a varicon that is resistant to changes in temperature and aging. In addition, by sandwiching an RF amplification stage using a 4-pole MOS FET and installing a multiple tuning circuit, excellent interference rejection capability is obtained.
VHF low-noise -noise transistor is used for the local oscillator circuit, and it is combined with an oscillation coil with aluminum core and steatite to constitute a high-performance local oscillator circuit.
The signal generated by the local oscillator circuit is supplied to a balanced mixer using a dual gate 4-pole MOS FET through a buffer circuit using an emitter follower, and a narrow-band AGC is applied from the IF stage to the RF amplifier stage.
As a result, excellent reception performance is obtained.
It is equipped with a servo tuning system that detects frequency deviation and tuning deviation by a wide circuit including an IF circuit as well as a front end, and draws it to a characteristic tuning point.
As a result, even if the transmission frequency is shifted, it follows and adjusts to the personality.
An auto high blend switch is mounted. When mpx hi-blend is set to auto, the high blend circuit is automatically turned on / off depending on the strength of the input radio wave.
When a low-frequency broadcast is received, a high-blend circuit operates to mix the left and right channels in the high-frequency range, where noise becomes a nuisance, to reduce high-frequency noise.
In the manual position, the high blend circuit always operates regardless of the radio wave condition.
The AF circuit is equipped with a complete complimentary service SEPP circuit with ± 2 power supplies and ICs.
It is equipped with an FM low-noise recording system that uses pre-emphasis (raising the high-frequency band to reduce noise), which is used when broadcasting stations send out signals. This enables recording and playback with less tape hissing.
It has a built-in pink noise generator that can be used to set recording levels.
The setting is completed when the selector knob is set to Pinknoise and the recording level is adjusted to around -6dB.
There was a wood case sold separately.
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Model Rating
| Type | FM/AM Tuner |
| FM Tuner Section | |
| Receiving frequency | 76 MHz to 90 MHz |
| Sensitivity | 0.9 μ V (75 Ω) |
| Harmonic distortion factor (at 100% modulation) | mono:0.15% stereo:0.25% |
| SN ratio (400 Hz, 100% modulation) | 80dB |
| Frequency characteristic | 20 Hz to 18 kHz + 0.2 -0.8 dB |
| Selectivity (IHF) | 85dB |
| Capture ratio | 1.0dB |
| Image interference ratio | 105dB |
| IF interference ratio | 105dB |
| Spurious interference ratio | 100dB |
| AM suppression ratio | 55dB |
| Stereo separation | 45dB(1kHz) 35dB(10kHz) |
| Leak Carrier (19 khz) | -65dB |
| Antenna terminal | Unbalanced : 75 Ω |
| <AM Tuner Section> | |
| Receiving frequency | 525 kHz to 1605 kHz |
| Sensitivity (S/N ratio 20 dB) | 30 μ V |
| Selectivity | 25dB |
| Image interference ratio (1000 kHz) | 80dB |
| IF Disturbance Ratio (1000 kHz) | 85dB |
| <General> | |
| Output voltage | Output : 0.077 v ~ 1.55 v Rec Out:0.6V |
| Pwer | 100 VAC, 50Hz/60Hz |
| Power consumption | 22W |
| External dimensions | Width 450x Height 173x Depth 385 mm |
| Weight | 8.6kg |
| Attachment | Feeder antenna x1 Connection code x1 |
| Sold Separately | Wood Case SH-780 (¥ 4,000) |