Marantz ST-55 (1978–1980)
The Marantz ST-55 is a solid-state FM/AM stereo tuner built in Japan from 1978 to 1980. The design is plain analog - superheterodyne circuitry with 4 FETs, 5 ICs, 16 transistors, and 17 diodes. Tuning is a traditional dial and string, not the digital synthesis that was just starting to show up in higher-end gear. The silver-and-black face has a signal strength meter. It retailed for $240.
Documentation on this model is thin. What the record shows is a competent mid-range tuner of the late 1970s. It covers FM plus MW bands, with a frequency response of 30 Hz to 15 kHz, distortion rated at less than 0.15%, and signal-to-noise of 70 dB mono and 68 dB stereo. It draws 12 watts, measures 416 × 93 × 320 mm, and weighs 5.4 kg. Rear-panel connections are minimal - two antenna inputs and a single line output.
Beyond its listing in equipment directories, almost nothing else is recorded about this model. No user reviews, no service advisories, and no collector-market pricing data have surfaced. It appears to have been a solid, unremarkable tuner from the late-70s Marantz catalog. A period survey of tuners in HiFI-Stereo (February 1996, p.74) grouped the Marantz ST-50 alongside other AM/FM tuners of the era, noting its digital-synthesis design and switchable IF bandwidth.
Known Specifications
- Type: FM/AM stereo tuner (superheterodyne)
- Years of manufacture: 1978–1980
- Made in Japan
- Tuning range: FM 88–108 MHz; MW 530–1,600 kHz
- Tuning display: Dial/string with signal strength meter
- Frequency response: 30 Hz – 15 kHz
- Distortion: less than 0.15%
- Signal-to-noise: 70 dB (mono), 68 dB (stereo)
- Semiconductors: 4 FET, 5 IC, 16 transistor, 17 diode
- Power consumption: 12 W
- Dimensions: 416 × 93 × 320 mm
- Weight: 5.4 kg
- Original price: $240
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