Sansui 551 (1974-1976)
FM/AM receiver from Sansui's early-1970s "xx1" series with 16 watts per channel and discrete main amplifier components
Overview
The Sansui 551 is an FM/AM receiver produced from 1974 to 1976, part of Sansui's "xx1" lineup that includes the 221, 331, 441, 551, 661, 771, and 881. It features a silver faceplate paired with a faux wood-metal case and a green dial scale, reflecting the early-1970s design aesthetic with knobs along the bottom and a radio dial that extends two-thirds across the top. Internally, the design is simple, relying on discrete main amplifier components and a minimal number of semiconductors to deliver 16 watts per channel. The unit includes phono, aux, and tape inputs, speaker A/B selection, tone controls, and a loudness switch.
Specifications
| Year of Production | 1974-1976 |
| Power Output (RMS) | 16 watts per channel (8 Ω) |
| Total Harmonic Distortion | 0.8% |
| Frequency Response | 15 Hz to 30 kHz |
| Input Sensitivity / Impedance (Phono) | 2.5mV / 50k Ω |
| Input Sensitivity / Impedance (Aux, Tape) | 150mV / 50k Ω |
| Speaker Load Impedance | 4Ω (minimum) |
| Semiconductors | 1 x FET, 5 x IC, 30 x transistors, 10 x diodes, 1 x zener diode, 1 x LED |
| External Dimensions | 424 x 135 x 285 mm |
| Weight | 8.6 kg |
| Power Requirements | 100 / 117 / 220 / 240 V, 50 / 60 Hz |
Design
The power stage uses a SEPP quasi-complementary circuit, and a dual gate MOS FET is used in the FM front-end section to improve reception characteristics. A high-gain IC handles the phono equalizer, and ICs are also present in the tuner section. The amplifier relies on discrete components for the main stage, contributing to its compact internal layout. The construction includes a silver faceplate coupled with a faux wood-metal case and a green dial scale, consistent with early-1970s styling.
Context
The Sansui 551 is part of Sansui's "xx1" receiver series, which includes models 221 through 881. According to Classic Receivers, it was described as the smallest receiver in the xx1 lineup, though this conflicts with the existence of lower-numbered models.
Market
A restoration kit is available for the Sansui 551, priced at $173.50 including shipping, containing high-quality electrolytic and film capacitors, diodes, a bridge rectifier, thermistor, lamps, fuses, and instructions. Common issues include aging capacitors, IC failures in the phono and tuner sections (which can be difficult to replace), a buzzing/flickering problem related to a switch, and recurring fuse blowouts indicating downstream component failure. Owners report that the unit may emit a 5-second electrical tension sound at power-on until the circuit stabilizes.
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Related Models
- Sansui PM C100 (Unknown)
- Sansui 6060 (1975-1977)
- Sansui AU 555 (1968-1971)
- Sansui CA 3000 (1974-1977)
- Sansui GX 5 (1974-1976)
- Akai AM-2850 (1975)
- Akai AP-206 (1975)
- Nakamichi BX-1 (1985)
- Acoustic Research research-ar-17 (1978)
- Acoustic Research AR-19 (1994)