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Item is in “like new” with no scratches, gouges or dents in the face plate and has never been rack mounted. Item works as it should and sounds fantastic. See the you tube like for video. Made in the USA.Description: High-definition vacuum tube stereo power amplifier has a silver-toned front panel with black rack handles. This unit is a Model D-115 from Audio Research and features three large black transformers and a perforated black metal cage protecting the internal tubes. The front panel has a power toggle switch, two fuse holders, and indicator lights. The chassis is black metal.The Audio Research D-115 is a classic all-tube stereo power amplifier from the early 1980s, produced by the respected American high-end audio manufacturer Audio Research Corporation (ARC). It was introduced around 1983 and produced until about 1989 (with a MkII revision in 1984). It is known for its musical, lush, and non-fatiguing sound signature typical of well-designed tube amps from that era. Key Specifications• Power Output: 100 watts per channel (both channels driven) into 16 ohms, 20 Hz–20 kHz, <1% THD. (Some reports note it can approach ~115W before clipping.)• Tube Complement: 8 × KT77 output tubes (4 matched pairs), plus smaller tubes including 1 × 6550, 1 × 12AT7, and 7 × 6DJ8/ECC88 (or equivalents). • Power Bandwidth: 10 Hz–60 kHz (–3 dB).• Input Sensitivity: ~1.2 V RMS (some sources list variations like 0.6 V depending on version).• Input Impedance: 75 kΩ.• Damping Factor: ~20 (relatively low, typical for tube amps; favors higher-impedance or more linear speaker loads).• Power Consumption: ~400W idle; full supply rated around 1000W / 280 joules storage.• Dimensions: Approx. 19” W × 7” H × 16.5” D (48 cm × 18 cm × 42 cm).• Weight: ~31 kg (68 lbs) — very heavy due to multiple large transformers. It features separate output taps for 4, 8, and 16 ohm speakers. Biasing the output tubes can be involved and requires care (high voltages present), and some owners note it’s not the easiest amp to service due to its dense internal layout. Sound CharacteristicsReviewers and owners often describe the D-115 as:• Balanced and smooth with a rich, full midrange and emphasis on vocals (lush and intimate).• Spacious soundstage with good dynamics and rhythm, though bass extension and treble may be less “etched” or extended compared to solid-state or later ARC designs.• Forgiving and non-fatiguing, excelling with conventional dynamic speakers (better with higher/linear impedance loads like many 8-ohm designs; some success reported with certain electrostatics or planars). It pairs well with ARC preamps (e.g., SP-6/SP-10 era) but works in mixed systems. It’s praised for making music engaging rather than analytical.History and ContextThe D-115 was part of ARC’s “High Definition” series and was a popular high-power tube amp option before the company shifted toward hybrids like the Classic 60. Original MSRP was around $2,995–$3,295. It remains sought-after on the used market for its build quality and sonic character.
US$2,250 is fair to slightly attractive for a D115, not a steal but comfortably in the zone for a desirable vintage Audio Research tube amp. The closest usable market anchors put the D-115 MKII around US$2,165 on Reverb, while period pricing was US$2,995 in 1994 and the original launch price was US$3,250; that puts this listing a touch above one recent ask but well below its historical pricing.
The appeal is the classic Audio Research mix of power, tonal richness, and control—the D115 is a respected stereo tube amp with enough muscle to drive real speakers, not just easy loads. If the unit is clean, stable, and recently serviced, that adds real value; with an amp of this age, the big buyer check is always the condition of tubes, bias health, and any service history, since those can swing ownership cost more than a few hundred dollars.
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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