Sansui AU 101 (1971-1973)

Fifteen watts a side, a satin-black face, and a midrange that makes you stop flipping records and sit there.

Overview

The AU 101 is the smallest door into Sansui's AU series. Built from 1971 to 1973 as the entry-level integrated, it carried the same all-silicon solid-state design as the bigger AU-555A. Sansui's own owner's literature says it incorporates "state-of-the-art features of the more powerful Sansui AU-555A," with a professional control layout and a satin-black control panel. It is a control amplifier in the old sense of the term: line stage, phono stage, tone controls, and a modest but honest power section, all in one compact chassis.

The headline number is small. Continuous power is rated at 15/15 watts into 8 ohms, with 18/18 watts available into 4 ohms, and the IHF music-power figure climbs to 50 watts into a 4-ohm load on peaks. Fifteen watts is not a lot, and anybody shopping on wattage alone in 1972 would have walked past it. The rest of the spec sheet is where it gets interesting: a power bandwidth of 25 to 40,000 Hz, a frequency response of 20 to 60,000 Hz ±2 dB at normal listening levels, and total harmonic distortion under 0.8% at rated output. Those are not entry-level numbers.

Sansui's own advertising leaned hard on that positioning. A 1971 campaign in Studio-Sound (April 1971, p.42) billed the "all-new 50 watt compact AU-101" as a control amplifier that "really has everything under control. Including cost," and pointed to its low-noise all-silicon transistors and a semi-complementary Darlington ITL-OTL design in the power amplifier section, backed by a double-safeguard protection system for the output devices. The same magazine, two years later, called it "a highly successful best-seller" whose tonal quality, versatility, ease of operation, and economy made it an inexpensive compact amplifier worth recommending (Studio-Sound, September 1973, p.45). That's marketing copy, not an independent bench test.

Key Features

All-Silicon, Semi-Complementary Darlington Output Stage

Eighteen transistors and four diodes make up the AU 101's discrete signal path. No op-amps, no integrated output modules. The power amplifier section uses a semi-complementary Darlington ITL-OTL topology, which means a capacitor-coupled output with the output devices arranged in a Darlington pair on one side. It is not DC-coupled, and it is not the same circuit as the direct-coupled designs that came later in the AU line. It is stable, simple, and easy to service. Sansui also built in a double-safeguard system to protect the output transistors.

Continuous Power: 15 Watts per Channel into 8 Ohms

Fifteen watts per channel into 8 ohms is the number. Into a typical 8-ohm bookshelf speaker of the era, something in the high-80s or low-90s dB sensitivity, fifteen watts is enough to fill a living room without the amplifier straining. The AU 101 also swings 18 watts per channel into 4 ohms, so it will drive a 4-ohm load, and its rated load impedance range runs from 4 to 16 ohms. It is not a headroom monster and it will not wake up a pair of low-efficiency acoustic-suspension speakers. Paired sensibly, it is sufficient.

Phono Stage: 3mV Sensitivity, RIAA NF Equalization

The phono input is a proper one: 3mV sensitivity into a 50k-ohm load, with RIAA NF-type equalization and channel separation better than 45 dB at 1 kHz. Hum and noise on the phono input is rated better than 65 dB, which is quiet enough that surface noise from the record will be the dominant hiss in the room. There is also a mono mic input at 4mV with flat equalization. Aux and tape-monitor inputs sit at 200mV, and the tape recorder DIN connection is also 200mV in, 30mV out.

Tone Controls and Loudness Compensation

Bass control gives ±13 dB at 50 Hz; treble gives ±10 dB at 10,000 Hz. The loudness control adds +8 dB at 50 Hz and +3 dB at 10,000 Hz — a contour that is designed to compensate for the ear's reduced sensitivity at low and high frequencies when listening at low volume, and which remains one of the more useful features on a low-powered amplifier because so much of the AU 101's life is spent at moderate levels. The selector switches between mic, phono, and aux, the tape monitor toggles between source and playback, and there is a simple speaker on/off switch. Nothing here is complicated, and nothing here is missing that a 1971 buyer would have wanted.

Dual A.C. Outlets on the Rear Panel

The rear panel carries two convenience outlets - one switched by the front-panel power switch, rated at 50 VA, and one unswitched at 150 VA. That's enough to hang a turntable and a tuner off the back of the amplifier without a separate power strip, and the switched outlet means the turntable goes off with the amp. Sansui's manual is emphatic about not exceeding those ratings. The amplifier's own line fuse is a 2A glass tube on 100-117V mains and 1.5A on 220-240V, and the manual warns against substituting wire or a higher-rated fuse.

Historical Context

Collectibility & Value

Clean AU 101s trade in the $150 - $300 range depending on condition and restoration status, and the model carries a collectibility rating around 7/10. It is not a flagship and it is not going to appreciate like an AU-999 or a big receiver. It does have a devoted following, and the price of entry is low.

Any AU 101 that has not been serviced in decades needs the same attention as any other early-'70s solid-state amplifier. The electrolytic capacitors come first. They dry out and drift, and a full recap is the difference between "it works" and "it works right." Crackling volume and tone controls are typical and usually respond to a proper cleaning, though replacement is sometimes the only permanent fix. DC offset should be checked, because it drifts with age and stresses the output transistors. Any unit where one channel sounds weak or distorted should be tested for failing transistors before it's run hard. The indicator bulbs need attention too. NOS replacements turn up, but finding them is a hunt.

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