Sony ST-S333ESXII (1987)
A high-end FM/AM tuner from Sony’s ES series, released in 1987 with advanced digital tuning and noise reduction technologies.
Overview
The Sony ST-S333ESXII is an FM/AM tuner released in 1987 as part of Sony’s high-fidelity ES (Elevated Standard) line. Designed for audiophiles seeking precise reception and low distortion, it features 20 preset memories, multiple tuning modes, and a suite of proprietary signal-processing technologies aimed at optimizing FM reception and stereo decoding. It includes an FM feeder antenna and is built with mechanical isolation techniques to reduce acoustic interference.
Specifications
| Practical sensitivity | 0.9 μV/10.3 dBf |
| Harmonic distortion factor (1 kHz, wide) | mono:0.004% stereo:0.0075% |
| Effective selectivity | wide:65dB(400kHz) narrow:65dB(300kHz) |
| Frequency response (1 kHz, stereo) | 15 Hz to 15 kHz + 0.2-0.5 dB |
| Spurious interference ratio | 120 dB or more |
| Signal-to-noise ratio | mono:100dB stereo:92dB |
| Separation (1 kHz) | 65dB |
| Power consumption | 16W |
| External dimensions | Width 470x Height 86x Depth 345 mm |
| Weight | 5.2kg |
| Attachment | FM feeder antenna |
Design
The ST-S333ESXII uses analog sense tuning via a physical dial, with manual, auto, and preset scan modes. It features 20 station presets and a program memory function for timer-based listening across four stations. A microcomputer manages operations and powers down after approximately 10 seconds of inactivity. The tuner employs a direct comparator with a PLL IC handling frequencies up to 220 MHz, with a 100 kHz comparison frequency. It includes the SST (Super Sound Tracing) circuit, which divides the 76–90 MHz range into four bands to reduce front-end distortion, and features WOIS, WODD, and WODSD systems to optimize IF waveform, detection, and digital stereo decoding. The design uses an ES substrate with selective resist material, an ES filter for transformer winding characteristics, and replaces the traditional LC filter with an active MPX filter. The transformer and chassis are mechanically floated using materials with differing acoustic impedance.
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