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The asking price of US$30 is fair, sitting right at the median of the typical used market for the Optimus SA-155, which ranges from US$28 to US$33 based on 24 recent comparable listings. This is not a bargain, but it is a solid, honest price for a well-regarded unit, especially given that the listing age and generation do not introduce significant timing concerns or replacement-model risks.
This mini integrated amplifier is well-loved for its surprisingly warm sound and unique, non-defeatable loudness contour that delivers extended bass response despite its modest 1.8 watts RMS per channel. Its compact form factor, front-panel 1/8-inch input for portable devices, and ability to function as a simple phono preamp make it a versatile, low-cost addition for a secondary setup or beginner system. At US$30, with no noted condition issues, this represents a genuine buying opportunity for an enthusiast seeking a reliable, original-owner piece with included accessories.
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.
