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Vintage solid state audiophile amplifier. Works perfectly. Like many amplifiers of this era, it has a fan to keep it cool is quiet. Fantastic sounding amplifier. Very precise with wide, even frequency range. Super clean sound. Silent noise floor. Comes with power cord and original box with factory packaging.Here are the specs:
The Audio Research SD135 stands out as a rare solid-state gem from ARC's late-2000s lineup, blending tube-like musicality with 130W/ch punch and blistering 0.4Hz-300kHz response—ideal for demanding loads like planars. At USD 1,150, this is a screaming bargain; recent used sales hover USD 1,500-7,200, with pristine examples rarely dipping below USD 2,000.
Buyers must verify the cooling fans spin quietly (they're prone to failure after 15+ years) and check for tube replacements or blown outputs, as some older units have needed costly repairs from speaker mismatches. Insist on the manual, original power cord, and a recent service history to avoid inheriting headaches.
Independent perspective — not a price guarantee. Always verify condition, accessories and provenance before purchase.
Audio Research Corporation, founded in 1970 in Minneapolis, Minnesota, by William Z. Johnson, traces its roots to his pioneering work in custom audio electronics during the 1950s and his operation of a specialty retail store through the mid-1960s. After a brief stint selling his designs to a larger firm, Johnson regained independence to establish ARC with a singular mission: advancing the state-of-the-art in music reproduction. From modest beginnings in the back of his shop, the company evolved into one of America's oldest continuously operating high-end audio manufacturers, now housed in a state-of-the-art 48,000-square-foot facility in Maple Grove, Minnesota.
ARC specializes in performance-driven electronics, renowned for vacuum-tube amplifiers, preamplifiers, and electronic crossovers that emphasize sonic purity over flashy features or aesthetics. Drawing on circuit designs rooted in the 1950s, the brand integrates tubes into modern contexts, delivering what it calls "high definition" sound through genuine technological advances. While not venturing into speakers, turntables, DACs, headphones, or cables, ARC's focused lineup prioritizes amplifiers and preamps that set benchmarks for musical realism.
Positioned at the pinnacle of high-end audio, Audio Research is hailed as a true originator of the genre, commanding respect among audiophiles for its unwavering commitment to excellence and innovation. Enduring the 1970s tube revival against solid-state dominance, ARC thrives via elite specialist retailers worldwide, standing alongside peers like Conrad-Johnson as a vintage-inspired yet forward-thinking force in the niche boutique market.
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