The Optonica SM-4000 is a stereo power amplifier developed by Optonica, a brand under Sharp. It was released during the late 1970s or early 1980s, a period when Sharp was marketing high-end audio equipment under the Optonica name. The SM-4000 features solid-state circuitry and is designed for high-fidelity audio performance, emphasizing accurate sound reproduction. The design typically includes a brushed aluminum faceplate and robust construction, contributing to its characteristic aesthetic and durable build.
