RADAR is a price search engine. We link to the original listing — we never sell direct. Transactions happen on the source site.
Are you looking for an inexpensive way to add a compact stereo amplifier, or expecting full-size hi-fi performance? At US$18, this is a strong deal: it sits well below the recent comparable range, with the 25th percentile at US$25, the median at US$30, and the 75th percentile at US$35.
The SA-155 is well regarded as a simple, practical mini amp for desktop systems, secondary rooms, vintage sources, or modest bookshelf speakers. Its appeal is straightforward operation and useful everyday power in a tiny chassis, rather than refinement or high-current drive. At this price, it is worth pursuing if the seller confirms both channels work cleanly, the volume control is quiet, and the power supply is included. Any included cables are a bonus, but even without extras, US$18 leaves plenty of room for a worthwhile experiment.
Independent perspective — not a price guarantee. Always verify condition, accessories and provenance before purchase.
Optimus is best known as a RadioShack private-label audio brand rather than an independent hi-fi manufacturer. The name traces back to RadioShack’s in-house branding, with “Optimus” used on some products from the late 1960s and more broadly on audio gear in the 1980s and 1990s. It does not have a clearly identifiable standalone founder in the way a dedicated hi-fi brand would; its heritage is tied to the RadioShack retail chain in the United States.
The line covered a broad range of consumer electronics, including stereo receivers, amplifiers, speakers, cassette decks, turntables, and later some home-theater and portable audio products. Depending on the era, many Optimus components were sourced from overseas OEM manufacturers, especially in Asia, and sold through RadioShack’s stores as house-brand alternatives to mainstream consumer audio lines.
In the market, Optimus sits firmly in the mass-market and mid-fi category rather than the high-end segment. Today it is mostly remembered by vintage-audio collectors and RadioShack enthusiasts, with certain receivers and speakers drawing interest for their retro appeal and occasional value. It is not generally regarded as a boutique or audiophile-first brand, but some models remain noteworthy for solid build and nostalgic charm.
See all Optimus listings on RADAR.
