Marantz ST-64 (1984)

The Marantz ST-64 is a digital synthesizer tuner released in 1984. It sold for ¥44,800 in its home Japanese market. It dates from the mid-1980s, when Marantz was moving from the analog tuners that built its reputation to quartz-locked digital designs. The ST-64 was built with an emphasis on sound quality, and it inherits technology from the SH-T10, a highly regarded Marantz analog tuner from a few years earlier.

It covers the Japanese FM band of 76-90 MHz plus AM from 531-1,602 kHz. A quartz PLL synthesizer handles the tuning. A FINE tuning function adjusts in 10 kHz steps depending on radio wave conditions, which helps in difficult reception areas. The front end is a pure electronic 4-stage design with a high-sensitivity MOS FET, and anti-birdie filters are fitted to eliminate beat interference. The IF stage switches between WIDE for strong signals and NARROW for weak ones. The detector section uses ultra-wide-band ratio detection. Oxygen-free copper wire runs from the power transformer to each stage.

The front panel holds 8 FM and 8 AM presets with one-touch selection. The memory also stores your FINE tuning and IF stage settings for each station. A last-station memory recalls where you were listening when you power back up. A program recording function can be set to capture up to six stations, handy for timed off-air recordings in the cassette era. The unit measures 416 × 73 × 300 mm and weighs 3.3 kg. It draws 12W from a 100V AC supply. The wooden side panels (WST-64) were sold separately for ¥4,000.

Documentation on this model is thin. Most of what's recorded comes from the Audio Database listing and a handful of classifieds. One owner of the closely related ST-64L variant noted it "receives very easily and many stations," and a seller of the ST-64 itself described it as exceptionally well-preserved with flawless technical operation and quality sound. The ST-64L appears in the same service manual as the ST-64, which suggests they are near-identical, but no source explicitly confirms the relationship. The tuner was often paired with Marantz amplifiers like the PM 64 MK II and PM-45 in period system setups.

Specifications at a glance:

Type: Digital synthesizer tuner (FM/AM)
FM range: 76–90 MHz; sensitivity 10.3 dBf / 0.9 µV (75Ω)
FM THD: 0.05% (1 kHz, stereo, wide); S/N: 80 dB (mono)
FM frequency response: 30 Hz–15 kHz, +0 / −0.5 dB; stereo separation: 60 dB (wide)
AM range: 531–1,602 kHz; sensitivity 300 µV/m; S/N 58 dB; THD 0.2%
Presets: 8 FM + 8 AM, with FINE tuning and IF mode memory
Dimensions: 416 × 73 × 300 mm; weight 3.3 kg
Power: 100V AC, 50/60 Hz, 12W