SONY ST-JX500
¥ 42,000 (sold on August 21, 1982)
Commentary
FM/AM tuner that uses Sony's original direct comparator system.
By adopting a high-speed PLL-IC developed by Sony, we have adopted a direct comparator method in which the comparison frequency of the synthesizer tuner is set to 100 kHz, which is the same as that of the receiving step. This greatly reduces noise and beat and improves the SN ratio.
A total of 10 FM/AM stations can be preset at random. This memory uses a multi-process memory that stores settings such as muting ON/OFF.
It is equipped with a program memory function that makes it possible to record messages from several stations.
By connecting an optional program timer, you can call up to four specified preset stations in order.
It is equipped with a manual tune function that makes it easy to find weak electric field stations. In addition, it is equipped with three tuning methods : a sweep tune that searches for stations in the band one after another and receives radio waves for about four seconds and moves to the next, and an auto tune that automatically finds a station.
It is equipped with a memory scan function that allows you to recall preset stations one after another and check programs.
It is equipped with a centralized display by FL display tube.
A dual-gate MOS FET is used for the front end.
Oxygen-free copper wire with polarity indication is used for the power cord.
Uses carefully selected audio-only parts.
Model Rating
| Type | FM/AM Tuner |
| Circuit system | PLL digital frequency synthesizer Quartz lock system, superheterodyne |
| FM Tuner Section | |
| Receiving frequency | 76 MHz to 90 MHz |
| Antenna terminal | 75 Ω unbalanced / 300 Ω balanced |
| Intermediate frequency | 10.7MHz |
| SN ratio 50 dB sensitivity | Mono : 3.5 μ V (IHF) / 16.1 dBf (new IHF) Stereo : 43 μ V (IHF) / 37.9 dBf (new IHF) |
| Practical sensitivity | 1.8 μ V (IHF) / 10.3 dBf (new IHF) |
| Signal-to-noise ratio | mono:90dB stereo:88dB |
| Harmonic distortion factor (1 kHz) | mono:0.06% stereo:0.09% |
| Cross modulation distortion factor | mono:0.06% stereo:0.09% |
| Stereo separation | 55dB(1kHz) |
| Frequency characteristic | 30 Hz to 15 kHz + 0. 2-0. 5 dB |
| Effective selectivity | 80dB(400kHz) 70dB(300kHz) |
| Capture ratio | 1.0dB |
| AM suppression ratio | 65dB |
| Image interference ratio | 80dB |
| IF interference ratio | 90dB |
| Spurious interference ratio | 100dB |
| RF intermodulation interference ratio | 74dB(IHF) |
| Carrier leak suppression ratio | 76dB |
| Muting level | 30dBf |
| Auto-tuning level | 30dBf |
| Output Level / Impedance | 750mV/2.2k Ω |
| <AM Tuner Section> | |
| Receiving frequency | 522 kHz to 1,602 kHz |
| Antenna | Built-in, with EXT terminal |
| Intermediate frequency | 450kHz |
| Sensitivity | 46dB/m (built-in ANT) 100 μ V (EXT ANT) |
| Signal-to-noise ratio | 55dB(50mV/m) |
| Harmonic distortion factor | 0.3% |
| Selectivity | 38dB(10kHz) 35dB(9kHz) |
| Image interference ratio | 42dB |
| <General> | |
| Power supply voltage | 100 VAC, 50Hz/60Hz |
| Power consumption | 11W |
| External dimensions | Width 430x Height 55x Depth 300 mm |
| Weight | 2.9kg |
| Attachment | FM ribbon antenna F-type antenna plug Station name display label Stereo connection code |