Marantz St-5
¥ 64,800 (released in 1979)
Commentary
FM/AM tuner that uses a quartz-lock digital synthesizer system.
The front end is equipped with a quartz-locked digital synthesizer system. In this system, the local frequency is accurately locked at 100 kHz for FM and 9 kHz for AM based on a reference signal from a crystal oscillator. This system improves stability against environmental changes such as temperature and humidity, and minimizes distortion due to misalignment of tuning. In addition, with the synthesizer system, in which the frequency is selected by changing the voltage applied to the varicap, everything is controlled electronically, so there is no mechanical operation part and no misalignment due to external shocks such as vibration.
The St-5 has a built-in preset mechanism that allows you to preset a total of 14 stations (7 FM stations and 7 AM stations). With its unique mechanism, stored stations do not disappear even after the power is turned off.
It uses a convenient auto-tuning system that allows you to select stations accurately without having to remember the frequency of each station. Manual operation is also possible by switching the tuning switch to the normal switch.
The frequency display is directly displayed on the digital display by counting down the quartz-locked local frequency. As a result, the indication error is 0. At the best tuning point, there is no distortion or degradation of separation.
The front end with improved tuning performance using a quartz-lock synthesizer system uses a low-noise dual-gate MOS-FET to achieve high frequency amplification characteristics with excellent distortion factor and S/N ratio.
The IF stage, which had been difficult to achieve both reception and sound quality, is divided into a main IF stage and a sub IF stage to improve both reception and sound quality.
In addition, a PLL pilot canceler circuit is used in the MPX stage to improve separation characteristics over a wide range.
The digitally displayed frequency is designed so that there is no deviation in tuning, but it is equipped with a signal intensity meter by LED so that the signal strength can be read directly.
In addition, this meter can be used for multi-path observation by switching the switch. It can easily check the direction without Radio noises, and can be used for antenna setting to draw out the performances.
There was a mahogany cabinet as an option sold separately.
.JPG)
Model Rating
| Type | FM/AM Tuner |
| FM Tuner Section | |
| Receiving frequency | 76.1 to 89.9 MHz |
| Practical sensitivity of IHF | 1.8 μ V (IHF) 10.3 dBf (new IHF) |
| 50 dB quadrature sensitivity | Monaural : 2.5 μ V (IHF), 13.2 dBf (new IHF) Stereo : 36 μ V (IHF), 36.4 dBf (new IHF) |
| Signal-to-noise ratio | Monaural : 78 dB Stereo : 73 dB |
| Harmonic distortion factor | Mono, 1 kHz : 0.08% (WIDE), 0.15% (NARROW) Stereo, 1 kHz : 0.15% (WIDE), 0.25% (NARROW) |
| Frequency characteristic | 30 Hz to 15 kHz (+ 0.2 dB, -1.5 dB) |
| Capture ratio | 0.9dB(WIDE) 1.5dB(NARROW) |
| Effective selectivity | 42dB(WIDE) 75dB(NARROW) |
| Image rejection ratio | 80dB |
| Intermediate frequency interference ratio | 100dB |
| AM suppression ratio | 60dB |
| Stereo Separation (1 kHz) | 50dB(WIDE) 45dB(NARROW) |
| <AM Tuner Section> | |
| Receiving frequency | 531 to 1602 kHz |
| Sensitivity | 20 μ V |
| Signal-to-noise ratio | 50dB |
| Harmonic distortion factor | 0.5% |
| <General> | |
| Rated power consumption | 10W (Electrical Appliance and Material Control Law) |
| Pwer | 100 VAC, 50/60Hz |
| External dimensions | Width 416x Height 73x Depth 300 mm Width 474x Height 100x Depth 320 mm (Mahogany Cabinet Dimensions) |
| Weight | 4.5kg |
| Sold Separately | Mahogany Cabinet WC-72N (¥ 11,000) |