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The asking price of US$34 for the used Optimus SA-155 sits exactly at the 75th percentile of the typical used market, making it ambitious but not unreasonable given current listings. While the median is US$30 and the 25th percentile is US$28, this price exceeds the median by US$4, so it is fair only if the unit is in pristine, original-owner condition with all accessories included.
This compact 1990s mini amplifier is well-regarded for its non-defeatable loudness contour that delivers extended bass response despite producing only 1.8 watts RMS per channel. Its versatility shines with switchable phono inputs for both magnetic and ceramic cartridges, plus tape in/out and a front AUX jack, making it a worthwhile buy for efficient speakers or as a phono preamp feeding a modern amplifier. If the listing is clean and complete, this represents a genuine buying opportunity for a rare, well-loved vintage piece.
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.
