Kenwood Supreme 600 (1977–1979)
At 21.3 kg, it arrives like a declaration - this is not an amplifier for the timid.
Overview
The Kenwood Supreme 600 is an integrated amplifier from the late 1970s, built for people who wanted separates-level performance without the rack of components. The original Supreme models, the 700C and 700M, struggled in Japan. The integrated variants like the 600 found quiet admiration abroad, where the build quality and engineering stood out even next to high-end separates.
Owners report it can compete with separates costing much more. The Supreme 600 puts dual power transformers into a chassis that outweighs even the KA-9100. It was built to order. It shares the same January 1976 export service manual as the Model 650 and Model 500, so the late-Supreme lineup uses the same parts and the same design.
The Supreme 600 had no domestic advertising and was nearly invisible in its home market. It has since picked up a cult following. Collectors call it a "TOTL Built To Order Model." It combined high power with precision. It wasn't flashy.
Specifications
| Manufacturer | Kenwood |
| Product type | Stereo Integrated Amplifier |
| Production years | 1977–1979 |
| Power output | 2x 130W (8 Ω, 20 Hz – 20 kHz, 0.08% THD) |
| THD | < 0.08% (rated output into 8 Ω) |
| S/N ratio | 115 dB (short-circuited) |
| Frequency response | DC – 70 kHz (+0/-1 dB) |
| Damping factor | 50 at 8 Ω |
| Inputs | 2.5 mV / 30/50/100 kΩ (Phono 1), 150 mV / 50 kΩ (Tuner, Tape, Aux) |
| Low filter | 40 Hz, 12 dB/octave |
| High filter | 8 kHz, 12 dB/octave |
| Power consumption | 790W at full power |
| Dimensions | 44 x 15.4 x 38.8 cm |
| Weight | 21.3 kg |
Key Features
Dual Power Transformers for Maximum Stability
Unlike most integrated amplifiers of its era, the Supreme 600 has dual power transformers, which goes with its built-to-order status. They give clean, isolated power to the preamp and power amp stages, which minimizes crosstalk and voltage sag under load. That makes it a solid platform for difficult speakers, and owners still praise it for that decades later.
DC – 70 kHz Frequency Response with Minimal Feedback
The Supreme 600 holds a frequency response of DC to 70 kHz within ±1 dB. Kenwood didn't get there with brute-force feedback. The bare circuit characteristics were optimized first, and then shallow NFB was applied, which fits the Supreme series approach. The amplifier remains stable and detailed, and it avoids the "etched" sound of over-corrected designs.
Switchable Input Impedance for Phono 1
Phono 1 input offers selectable impedance settings—30 kΩ, 50 kΩ, and 100 kΩ—allowing users to match a wide range of moving magnet cartridges precisely. This level of flexibility was rare in integrated amplifiers and speaks to the Supreme 600’s ambition to serve as a true high-end hub for analog sources.
21.3 kg Chassis with Industrial-Grade Build
The Supreme 600 weighs 21.3 kg. The mass damps vibration and reduces microphonics. Owners note it feels heavier than the KA-9100, which was already known for its heft. The weight comes from the oversized transformers, thick steel shielding, and dense circuit layout inside.
Presence Control with 6 dB Boost at 800 Hz and 3 kHz
Beyond standard bass and treble controls, the Supreme 600 has a presence control with a 6 dB boost at either 800 Hz or 3 kHz. It allows fine-tuning of vocal and midrange clarity, a feature typically reserved for professional audio gear. It can also be used to adjust for room acoustics or speaker characteristics.
Loudness Compensation with Four-Position Boost
The loudness control has four stepped settings - +2, +4, +6, and +8 dB at 100 Hz - giving progressively stronger bass lift at lower volumes. Unlike simple on/off loudness circuits, the stepped approach gives finer control over compensation and preserves tonal balance without muddying the midrange.
Historical Context
The Supreme 600 belongs to the later Supreme series, a group of integrated amplifiers developed primarily for export. The original Supreme models like the 700C and 700M sold poorly in Japan, and the integrated variants - the 600, 650, and 500 - remained virtually unknown there. Kenwood did not advertise these models domestically, which added to their obscurity. The engineering lineage stayed intact: same service manual, same parts, same design philosophy as the earlier separates.
The Supreme 600 was never a mass-market product. It was built in limited numbers, to order, which makes it rarer.
Collectibility & Value
Today, the Kenwood Supreme 600 is recognized as a rare and significant piece of Japanese high-fidelity history. Market value ranges from $2,500 to $4,500 depending on condition and originality, with fully restored examples commanding premium prices. Collectibility is rated 9/10, reflecting its status as a "TOTL Built To Order Model" with near-mythical reputation among vintage audio enthusiasts.
Listings often mention "stratospheric asking prices" on eBay, and mint units in original packaging are exceptionally rare. Owners strongly recommend restoration, particularly capacitor replacement, to ensure long-term reliability.
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