Sansui AT-20

A Sansui model number with a manufacturer spec sheet on file and almost nothing else — no confirmed years, no period review, and one very large IHF power figure attached to it.

Overview

The AT-20 is the kind of entry that shows up sideways in this archive: a model number in a spec-sheet index, a line in a catalog, a mention in a thread that never resolves into anything. What the archive does have is a manufacturer document excerpt that explicitly names the AT-20, and that document supplies the only hard numbers on file. It lists an IHF music-power rating of 280 watts at 4 ohms, with 190 watts at 8 ohms, and a continuous output power of 60 watts × 4 at 4 ohms with each channel driven. Read that pairing carefully, because it tells you what kind of document this is. The 280-watt figure is music power — a peak, marketing-friendly number — while the continuous rating is the one that describes what the unit will actually deliver into a load over time. Four channels at 60 watts apiece into 4 ohms is the real story here, and it points toward a quadraphonic-era Sansui rather than a conventional two-channel piece. That reading is inference from the spec structure, not a confirmed product classification; the archive has no document that labels the AT-20 as a quad receiver outright.

What can be stated without hedging is the physical footprint. The same manufacturer document gives a weight of 22kg (48.5 lbs.) and dimensions of 538mm wide, 197mm high, and 362mm deep. That is a substantial chassis — heavy enough that moving it is a two-hand job, and wide enough that it will not slot into a modern rack without an overhang. The document also lists a power consumption figure of 150W rated and 470VA maximum, along with multi-voltage power requirements covering 100, 110, 117, 127, 220, 230, 240, and 250V. Multi-voltage taps on a Sansui of this description usually indicate a unit built for international distribution rather than a single domestic market, though the archive has no documentation confirming which markets the AT-20 was sold into.

The tuner and input sections in the manufacturer document are similarly detailed. FM tuning range is listed at 88 to 108 MHz with an IHF sensitivity of 1.8µV, a signal-to-noise ratio better than 65dB, and selectivity better than 70dB. AM covers 535 to 1605 kHz. Input sensitivity is given as 2.5mV at 50k ohms for Phono 1 and 2, 150mV for the two-channel AUX input, and 150mV for the discrete four-channel input. The document also describes the synthesizer/decoder as a Sansui New QS Circuit using Vario-Matrix — the company's own matrix quadraphonic decoding scheme. That is the strongest signal in the paperwork that this is a four-channel machine, and it lines up with the continuous 60 watts × 4 rating. It is worth being precise about what the archive does and does not know: the document names the Vario-Matrix decoder and the four-channel power rating, but no source on file confirms the AT-20's production years, its original retail price, or its place in Sansui's lineup.

Period coverage of the broader Sansui line is available and gives a sense of the company's engineering reputation in this era, even though none of it names the AT-20 specifically. Audio (April 1985, p.96) bench-tested a Sansui amplifier and measured 316 watts into 8 ohms and 443 watts into a 4-ohm load, with a damping factor above 267 at low frequencies — the kind of headroom that made Sansui's bigger amplifiers a byword among collectors. That measurement belongs to a different model and should not be read as a claim about the AT-20's performance. It is context for the brand, nothing more. The archive's position on this page is the same as it is for every thin entry: an accurate short page beats a padded speculative one, and the AT-20 is currently a short page with a genuinely useful spec sheet attached.

For anyone who owns one, the practical question is what the unit actually is. The Vario-Matrix decoder and the four-channel continuous rating suggest a quadraphonic receiver or integrated amplifier, but the archive has no document that states the product type outright, and it will not guess. If a rear-panel photograph, an owner's manual cover, or a catalog page turns up, this entry changes from a spec sheet with a model number attached into an actual profile. Until then, the numbers above are what the paperwork supports — a 22kg chassis, a 280-watt IHF music-power rating at 4 ohms, 60 watts × 4 continuous at the same load, and a Sansui QS Vario-Matrix decoder on board.