Kenwood KA-907 (1979–1980)

At 25.8 kg, it stakes a claim on the shelf.

Overview

The Kenwood KA-907 was built during the last stretch of Kenwood's "monster" period. It was the brand's most ambitious high-end integrated design, and it came just before the market moved toward compact separates and digital sources. Kenwood marketed it as a High Speed DC Integrated Amplifier. It was engineered to remove compromise from the signal path, input to output. Owners report an internal build rarely seen in an integrated unit: dual mono construction, discrete all-DC circuitry, and a power delivery system that borders on overkill. It was meant to compete with the elite from Accuphase, Luxman, and Yamaha, and out-engineer them.

It's an integrated, but it works more like a preamp and power amp combo in disguise. The design isolates left and right channels completely, with independent power supplies, massive transformers, and FET-based Class A driver stages. That is brute-force precision. The front panel is all aluminum with a semi-matte "frosted" texture. It brings a change in Kenwood's look, with angular knobs and switches that feel more surgical than decorative.

Specifications

Key Features

Dual Mono Design with Independent Power Supplies

The KA-907 enforces its dual mono construction. Each channel runs off its own regulated power supply, fed by what owners describe as "two massive" transformers. Four 18,000µF capacitors provide reservoir capacity that rivals standalone power amps of the era. The point is to prevent crosstalk or channel interaction, even under dynamic load, as well as to give power headroom. The result is a soundstage with exceptional focus and separation, where instruments don't bleed into one another, even at high volumes.

All-DC FET/Class A Pre and Driver Circuitry

True DC coupling runs from input to output, so there are no coupling capacitors to color or slow the signal. The preamp and driver stages use FETs in Class A configuration, which minimizes crossover distortion and keeps linearity across the entire dynamic range. That contributes to the amplifier's famously low THD and IMD figures. It also gives a sense of immediacy - transients arrive without hesitation, and decay trails fade into true silence.

Four-Parallel-Pair Output Stage with High-Speed Transistors

The output stage uses four parallel pairs of 2SA165 and 2SC2489 transistors, high-speed devices rated at 50MHz. They are configured with cascode bootstrap, current mirror, and constant current drivers. The high damping factor of 100 ensures tight grip over speaker cones, especially with demanding loads. Bass is deep and articulate, with punch that doesn't blur into bloat. The slew rate of ±230V/µs means the amplifier can track even the fastest musical transients without smearing.

Discrete, Symmetrical MC and MM Phono Stages

The phono section is a standout, especially for an integrated amp. The MC stage uses a three-stage symmetrical complementary circuit with low-noise transistors in the first stage, followed by a common emitter and emitter follower. Negative feedback links the first and third stages, while supplementary feedback from the second stage is applied to the first, reducing distortion and output impedance. The MM stage uses a DC-coupled FET input, which gives high overload capability and excellent signal-to-noise performance. Both stages are fully discrete, with precision-matched components instead of ICs.

ALPS Conductive Plastic 4-Gang Motorized Attenuator

The volume control is a high-grade ALPS conductive plastic 4-gang potentiometer, motorized for remote operation. Two gangs sit on either side of a buffer amplifier to improve linearity and reduce distortion at low listening levels. Owners report the motorized mechanism can develop noise over time, but the potentiometer itself is sturdy. When it works properly, it gives smooth, precise attenuation with minimal channel imbalance.

Frosted Aluminum Front Panel and Industrial Aesthetic

The KA-907 marks the start of Kenwood's "frosted" design language: a thick aluminum front panel with a semi-matte texture, angular knobs, and flush-mounted switches. It's a stark departure from the brushed finishes and rounded controls of earlier models. The chassis is engineered for rigidity, which minimizes microphonics and vibration. Build quality is industrial-grade, and the heatsink mass suggests the unit was built to run hard.

Historical Context

The KA-907 arrived in 1980 as Kenwood's flagship integrated amplifier, positioned as the top of their analog engineering. It shares significant design DNA with the earlier Model 600 series, and works as a refined, updated version of that platform. The amplifier and the KT-917 tuner came right before Kenwood shifted focus. Production was brief - 1979 to 1980 - and quantities were limited. A European variant, reportedly only 100 units, had gold trims and knobs and was distributed primarily in Germany. Collectors note this was the last of Kenwood's "monster" amplifiers.

Collectibility & Value

The KA-907 is considered one of the finest integrated amplifiers of its era, and its rarity pushes up demand. Aging components, particularly electrolytic capacitors in the power supply and protection circuits, mean fully functional units in original condition are uncommon. The motorized volume control is another known failure point, often requiring cleaning or replacement. Restoration is possible but labor-intensive, given the amplifier's complexity and dense layout. Working examples still command strong prices. No original pricing data is available, but current market interest remains high, with owners noting difficulty finding units even on secondary markets.

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