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One of the good ones from back in the day has your normal scratches and scuffs, works like it should. I am the second owner of this unit, and it's been well taken care of. The Kenwood KA‑8100 is a 1977–1979 DC‑coupled integrated amplifier rated at 75W per channel into 8Ω, 90W into 4Ω, with 0.03% THD and a frequency response extending from roughly 5Hz to 50kHz depending on source. Core Power & PerformancePower output:75W + 75W (8Ω) hifi-wiki.com90W + 90W (4Ω) hifi-wiki.comDynamic power: 330W (4Ω) hifi-wiki.comTotal harmonic distortion:0.03% at nominal power (8Ω) hifi-wiki.comAs low as 0.004% in some line-level measurements vintagetechnologyarchive.comFrequency response:5Hz–100kHz (Aux, DC on) vintagetechnologyarchive.com5Hz–50kHz (HiFi Engine spec) HiFi EngineDamping factor: 50 (8Ω) vintagetechnologyarchive.comInputs & SensitivityPhono MM: 2.5mV / 47–50kΩ, S/N 80–85dB vintagetechnologyarchive.com+1Phono MC: 0.1mV / 100Ω, S/N ~68dB vintagetechnologyarchive.comLine (Tuner/Aux/Tape): 150mV / 47–50kΩ, S/N up to 110dB vintagetechnologyarchive.com+1Controls & FeaturesBass ±7.5 to ±10dB depending on version vintagetechnologyarchive.com+1Treble ±7.5 to ±10dB vintagetechnologyarchive.com+1Loudness control with multiple boost levels hifi-wiki.comHigh, low, and subsonic filters (various cutoff frequencies) hifi-wiki.comDC‑coupled amplifier with dual power supplies and separate preamp supply vintagetechnologyarchive.comPre/power amp separation via rear jumpers hifi-wiki.comPhysical SpecificationsDimensions: ~430–440 × 149–153 × 370–403 mm (varies slightly by source) vintagetechnologyarchive.com+1Weight: 14.5–16 kg depending on documentation hifi-wiki.com+1Power consumption: 150W (rated), up to 600W max in some listings hifi-wiki.comSummaryThe Kenwood KA‑8100 is regarded as a high‑performance late‑1970s integrated amplifier featuring DC‑coupled design, dual power supplies, low distortion, and excellent phono capability, making it one of Kenwood’s most respected vintage units.
The KA-8100 has a strong reputation as a late-1970s Kenwood integrated: substantial, cleanly specified, and rated around 75 watts per channel into 8 ohms, with a useful phono stage and flexible connections. At US$650, this is a strong deal, sitting below the recent comparable range’s US$725 25th percentile and well under the US$800 median.
Its appeal is genuine: dual power-supply design, robust drive, broad inputs, and a sound that suits both vintage systems and demanding modern speakers. The main qualifier is simply age—this is a 1977–79 amplifier—so confirmation of quiet controls, balanced channels, clean relay operation, and stable bias matters. If it is working properly and cosmetically respectable, US$650 looks like an excellent buying opportunity rather than merely a fair price.
Independent perspective — not a price guarantee. Always verify condition, accessories and provenance before purchase.
Kenwood traces its origins to December 21, 1946, when it was founded as Kasuga Radio Co. Ltd. in Komagane City, Nagano Prefecture, Japan, by a group of entrepreneurs led by William "Bill" Kasuga. Emerging in the postwar era, the company initially produced electronic components and amateur radio gear, renaming to Trio Corporation in 1960 before adopting the Kenwood name in 1986 to appeal to Western markets—blending "Ken," a familiar name across Japan and America, with "Wood" evoking durability and Hollywood. This rebranding fueled rapid international growth, starting with a U.S. office in Los Angeles County in 1963.
The brand built its legacy on high-quality audio and communications equipment, excelling in home hi-fi amplifiers like the acclaimed 1970 Supreme 1 multichannel model, receivers, tuners, and speakers with innovations such as polypropylene cones. Kenwood also pioneered car audio systems, including the first audio/video amplifier for home theater in 1981 and anti-theft cassette decks, alongside professional two-way radios and amateur transceivers. While maintaining roots in consumer electronics, it expanded into automotive infotainment.
Today, as part of JVCKENWOOD since the 2008 merger with JVC, Kenwood holds a solid mid-tier position in car audio and professional communications, prized by enthusiasts for reliable performance and aftermarket upgrades. Its vintage home hi-fi gear from the 1970s and 1980s commands respect among collectors for robust build and warm sound, though it no longer dominates pure hi-fi markets.
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