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This is a buyer’s market for the category, and at US$33 this is basically a fair-to-slightly-strong ask rather than a standout bargain. Against your comps, it lands just above the US$30 median and below the US$35 75th percentile, so I’d read it as priced about right if the unit is clean and ready to use.
The SA-155 has a loyal following because it’s a tiny, straightforward amplifier that punches above its size for casual vinyl, desktop, or compact vintage setups. The upside is in simplicity and value: if it’s complete, works quietly, and includes the needed leads, it’s an easy little add-on rather than a project. At this price, the main check is just condition and functionality, since even modest vintage pieces are most satisfying when they’re plug-and-play.
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.
