Kenwood KX 800 (1979)

At 6.8kg, it sits on the shelf like a declaration: this is serious cassette engineering from the golden era of tape.

Overview

The TRIO KX-800—marketed under the Kenwood name—was released in 1979 as a high-end stereo cassette deck aimed at audiophiles who demanded precision and flexibility from their tape recordings. Priced at ¥59,800, it occupied a premium tier in the market, reflecting its advanced 3-head configuration and comprehensive feature set. Unlike many decks that compromised on head alignment or switching speed, the KX-800 used a combination 3-head system with separate recording and playback heads housed in a single ferrite assembly, allowing for dedicated record and playback functions without mechanical tape flipping. This design, paired with electronically controlled DC servo motors, delivered tight speed control and contributed to its remarkably low wow and flutter of 0.05% (WRMS) or less—

Despite its technical sophistication, the KX-800 made a few curious omissions. Notably, The absence of a monitor button suggests a streamlined, perhaps cost-conscious approach to the control layout, even as it retained high-end elements like Dolby noise reduction with three selectable levels and dual MPX filtering for clean FM recording. The mechanical logic control system, driven by the flywheel’s rotational force, gave the transport buttons a precise, tactile response with minimal effort—the switch can be pushed with a light touch.

The deck’s full-scale stabilized power supply ensured consistent voltage delivery across all circuits, a detail that mattered for maintaining headroom and minimizing crosstalk. Input isolation was also carefully considered: the line and microphone inputs operated independently, with the line signal routed directly to the recording amplifier, bypassing the mic preamp entirely. This prevented coloration and preserved source integrity, especially when dubbing from turntables or mixers. When using low-impedance (600 Ω) microphones, the ATT switch applied a -12dB pad to prevent overload—a thoughtful touch for field or live recording scenarios. LED indicators on the Record and Pause buttons helped prevent accidental operation, a small but meaningful safeguard during critical sessions.

Specifications

Key Features

Combination 3-Head System with Ferrite Assembly

The KX-800’s use of a 3-head configuration—record, playback, and erase—was a hallmark of high-fidelity cassette decks in the late 1970s. What set it apart was the integration of the record and playback heads into a single ferrite combination unit. The erase head, a ferrite double-gap type, provided thorough signal removal even at high bias levels, reducing print-through and improving recording clarity.

Mechanical Logic Control via Flywheel Drive

Instead of relying solely on solenoids or electronic logic boards, the KX-800 employed a mechanical logic control system powered by the rotational force of the motor’s flywheel. The result was a tactile, almost mechanical certainty in operation: buttons engaged with a deliberate click, and tape movement began instantly.

LED Indicators on Record and Pause Buttons

Visual feedback was integrated directly into the transport controls: both the Record and Pause buttons featured built-in LED indicators. This was not merely cosmetic—it served as a clear, immediate warning against accidental recording over valuable tapes. In dimly lit environments or during extended sessions, the glowing red LEDs made it easy to confirm the deck’s state at a glance.

Three-Level Dolby NR and Dual MPX Filtering

Noise reduction was handled by a Dolby noise reduction system with three selectable levels, allowing users to match the encoding to tape type and recording level. When engaged, Dolby boosted the signal-to-noise ratio from 52–54dB (off) to 62–64dB (on), a significant improvement for quiet passages. The inclusion of two MPX filter settings—likely broad and narrow—enabled users to suppress high-frequency FM stereo pilot tones that could interfere with tape bias and cause distortion. This dual filtering was particularly useful when recording from FM tuners, preserving high-end clarity without artifacts.

Full-Scale Stabilized Power Supply

The KX-800’s power supply was designed as a full-scale stabilized circuit, This prevented fluctuations due to line noise or load changes, ensuring consistent recording levels and frequency response. In an era when many manufacturers cut corners on power regulation, this attention to detail helped maintain the deck’s performance under varying conditions, especially during long recording sessions or in environments with unstable mains voltage.

Independent Line and Microphone Input Paths

The input architecture treated line and microphone signals separately. The line input bypassed the microphone preamp entirely, feeding directly into the recording amplifier. This preserved the tonal character of external sources—such as mixers or turntable preamps—without introducing additional gain stages that could add noise or coloration. The microphone input, rated at 0.19mV/18kΩ for 600Ω low-impedance mics, included an ATT switch that attenuated the signal by -12dB, preventing overload when capturing loud sources. This dual-path design reflected a professional-grade approach to signal routing, uncommon in consumer decks of the time.

Timer Standby Mechanism

Equipped with a timer standby function, the KX-800 could be programmed to power down after a set period of inactivity. This feature conserved energy and reduced wear on internal components during idle periods, particularly useful in home studio or broadcast environments where the deck might be left on for extended durations. While not a full auto-off recording timer, the standby mechanism demonstrated Kenwood’s attention to operational efficiency and longevity.

Single-Knob Tape Selector for Bias and EQ

One of the most user-friendly aspects of the KX-800 was its tape selector switch, which unified control over bias, playback equalization, recording equalization, and recording sensitivity into a single rotary knob. With positions for Normal, Ferrichrome, Chrome, and Metal tapes, the switch automatically adjusted all relevant parameters to match the selected tape formulation. This eliminated the need for manual bias tweaking or separate EQ switches, reducing setup errors and streamlining operation. For users cycling through different tape types, this integration was a significant usability advantage.

Collectibility & Value

No current market prices or valuation estimates are documented in available sources. However, user reports indicate that the most common failure point is degraded idler belts, consistent with many cassette decks of this era. One owner noted receiving a unit with a pre-existing belt issue, suggesting that rubber components may require replacement after decades of storage. Service and user manuals for the KX-800 are available through vintage electronics resellers, indicating ongoing interest among restorers. Given its 3-head design and robust build, the deck remains a candidate for refurbishment, though the lack of a monitor function may limit appeal

eBay Listings

2 PCS BELT LOT OF TWO BELTS FIT KENWOOD KX 800 KX-800 (2 BEL

$11.00

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