Kenwood KA-5040R (1991–1993)
The Kenwood KA-5040R is a stereo integrated amplifier from the early 1990s, produced roughly from 1991 to 1993 (some sources cite 1992) and sold new in Japan for ¥60,000. It's a big unit at 440mm wide, 147mm tall, 402.5mm deep and 11.6kg. It's finished in black and shipped with a system remote control that works with other Kenwood components bearing the Synchro mark.
The KA-5040R is rated at 80W + 80W into 8Ω (20Hz-20kHz, THD 0.03%) per audio-database.com, though some sources list 90W. Dynamic power is 105W into 8Ω and 175W into 4Ω. Kenwood specified a frequency response of 5Hz-80kHz (+0/-3dB, line to speaker) and a signal-to-noise ratio of 102dB (input shorted) for line-level sources. The phono stage handles both MM and MC cartridges with gain switching. It accepts 2.5mV/47kΩ for MM and 200µV/100Ω for MC.
Kenwood's design notes call the goal "sound beyond class." The amp has a 300VA power supply and a final transistor array rated at 80W × 8, four per channel. Six inert-gas-filled relays sit right after the signal inputs. They switch by relay instead of mechanical contacts, which keeps the signal path short and reduces crosstalk between inputs. A source direct circuit bypasses the tone, balance, and subsonic filters entirely, so the path runs from selector to volume pot to power amp. The grounding scheme puts all signal grounds at a single point at the speaker terminals. Speaker outputs accept banana plugs.
Solid information on real-world performance is thin. Owner reports are anecdotal but agree on a couple of points. Some units develop weak output or quiet/crackling channels with age, often traced to oxidation on internal contacts or prior repair work. A Polish resale listing from March 2025 asked PLN 600 (about $150) and described the amp as heavy, powerful, and clean. That listing's "2×95W" claim conflicts with Kenwood's own 80W rating, and the manufacturer's figure is the one to trust.
Known specs, in brief:
- Rated output: 80W + 80W (8Ω, 20Hz–20kHz, THD 0.03%); 90W + 90W (6Ω)
- Dynamic power: 105W + 105W (8Ω); 175W + 175W (4Ω)
- THD: 0.03% (20Hz–20kHz); 0.002% at 1kHz
- Frequency response: 5Hz–80kHz (+0/-3dB, line to speaker)
- S/N: 102dB (line, input short); 87dB (MM); 68dB (MC)
- Phono: MM 2.5mV/47kΩ; MC 200µV/100Ω
- Dimensions: 440 × 147 × 402.5 mm; 11.6kg
- Price new: ¥60,000 (circa 1991)
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