Expired
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This is a seller’s market for vintage Proton dual-mono amps right now, and the US$300 asking price for the Proton AA-2120 is ambitious. It sits well above the median of US$185 from your two recent comparable listings and exceeds the 75th percentile of US$243, making it a hard sell unless the condition is pristine or includes meaningful extras. While eBay shows scattered listings from US$99 to US$725, the tighter dataset you anchor on paints a clearer picture: US$300 is roughly 60% above median used value, so treat it as a premium ask rather than a bargain.
The AA-2120 is well-regarded for its true dual-mono design, where each channel shares only the cabinet and power switch, delivering clean 120W per channel with minimal crosstalk. It’s a favorite among enthusiasts who value straightforward, high-current power for dynamic speakers. If this unit is serviced, cleaned, and in original-owner condition with no missing accessories, the upside justifies some negotiation room—but at US$300 unknown condition, it’s not a clear buy. Wait for a unit closer to US$185–US$220 unless you get a solid deal on condition or service history.
Independent perspective — not a price guarantee. Always verify condition, accessories and provenance before purchase.
Proton Electronic Industrial Co., Ltd. emerged from Taiwan in 1981, establishing its base in Banciao, Taipei-Hsien, as a manufacturer targeting the U.S. consumer audio market with high-quality components. Linked to Fulet Electrical, which produced notable NAD amplifiers, the brand launched around 1984 to expand into consumer electronics, including acclaimed TV monitors like the 600M and 602M models. By 2009, it remained active, building on a heritage of precision engineering from shared facilities with brands like NAD and Dynaco.
The company focused on premium hi-fi gear optimized for real-world performance, emphasizing tuners, receivers, amplifiers, and integrated systems that drove everyday loudspeakers with exceptional clarity. While not delving into headphones or cables, Proton's lineup prioritized robust playback under practical listening conditions, from radio reception to vinyl and cassette sources, earning praise for its engineering rigor in the 1980s.
Proton holds a solid reputation in vintage hi-fi circles as a mid-tier powerhouse, favored by collectors for its reliable, high-value sound that punched above its price point. Positioned as an accessible alternative to elite brands, it appeals to discerning buyers seeking durable, no-nonsense performers rather than boutique exotica, with ongoing interest in its schematics and restored units.
See all Proton listings on RADAR.
