Kenwood KX 800 (1979)

The KX-800 weighs 6.8kg. It 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 for audiophiles who wanted precision and flexibility from their tape recordings. It was priced at ¥59,800, a premium tier that matched its 3-head configuration and long feature list. Many decks 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. That gave it dedicated record and playback functions without mechanical tape flipping. Electronically controlled DC servo motors held the speed tight, and wow and flutter was 0.05% (WRMS) or less.

The KX-800 left out a few things. There is no monitor button, which suggests a streamlined, perhaps cost-conscious control layout. It still kept high-end items like Dolby noise reduction with three selectable levels and dual MPX filtering for clean FM recording. The mechanical logic control system runs off the rotational force of the flywheel. The transport buttons respond precisely with very little effort, and the switch can be pushed with a light touch.

The deck has a full-scale stabilized power supply that keeps voltage consistent across all circuits. That helps with headroom and crosstalk. The line and microphone inputs work independently, and the line signal goes straight to the recording amplifier, bypassing the mic preamp entirely. This keeps coloration out and preserves the source, especially when dubbing from turntables or mixers. With low-impedance (600 Ω) microphones, the ATT switch applies a -12dB pad to prevent overload. LED indicators on the Record and Pause buttons help prevent accidental operation.

Specifications

Manufacturer	TRIO (brand name used by Kenwood)
Product type	Stereo cassette deck
Production years	Released in 1979
Original price	¥ 59,800
Track format	4-track 2-channel stereo
Motor	Electronically controlled DC servo motor
Heads	3 Head Recording / Playback : ferrite combination Erase : ferrite double-gap
Tape speed	4.76cm/s
Wow and flutter	0.05% (WRMS) or less
Fast forward and rewind speed	85 seconds or less (C-60 tape)
Frequency characteristic	Normal Tape : 30 Hz ~ 16 kHz (35 Hz ~ 14 kHz ± 3 dB) Ferrichrome Tape : 30 Hz to 18 kHz (35 Hz to 16 kHz ± 3 dB) Chrome Tape : 30 Hz ~ 18 kHz (35 Hz ~ 16 kHz ± 3 dB) Metal Tape : 30 Hz ~ 18 kHz (35 Hz ~ 16 kHz ± 3 dB)
Signal-to-noise ratio (Dolby NR OFF/ON)	Normal Tape : 52dB/62dB Ferrichrome Tape : 54dB/64dB Chrome Tape : 54dB/64dB Metal Tape : 54dB/64dB
Overall strain rate	1.2% or less (1 kHz, 0 VU, normal tape)
Recording bias	AC system, 105 kHz
Erasing method	AC erase
Input Sensitivity / Impedance	MIC : 0.19mV/18k Ω For Low Impedance (600 Ω) Microphone Line : 77.5mV/50k Ω
Output Level / Impedance	Line : 775mV/100k Ω load Head Phone : 8 ~ 16 Ω headphone
Power	100 VAC, 50Hz/60Hz
Power consumption	16W
External dimensions	Width 440x Height 133x Depth 355 mm
Weight	6.8kg

Key Features

Combination 3-Head System with Ferrite Assembly

The KX-800 uses a 3-head configuration - record, playback, and erase - which was common on high-fidelity cassette decks in the late 1970s. What set it apart was the record and playback heads combined into a single ferrite unit. The erase head is a ferrite double-gap type. It removes the signal thoroughly even at high bias levels, which reduces print-through and improves recording clarity.

Mechanical Logic Control via Flywheel Drive

The KX-800 does not rely only on solenoids or electronic logic boards. It uses a mechanical logic control system powered by the rotational force of the motor’s flywheel. Buttons engage with a deliberate click, and tape movement begins instantly.

LED Indicators on Record and Pause Buttons

Both the Record and Pause buttons have built-in LED indicators. They give a clear, immediate warning against accidentally recording over valuable tapes. The glowing red LEDs also make the deck’s state easy to confirm at a glance in dim rooms or during long sessions.

Three-Level Dolby NR and Dual MPX Filtering

Noise reduction is a Dolby system with three selectable levels, so the encoding can be matched to tape type and recording level. With Dolby engaged, the signal-to-noise ratio goes from 52-54dB (off) to 62-64dB (on), a big gain for quiet passages. There are two MPX filter settings, likely broad and narrow. They suppress the high-frequency FM stereo pilot tones that can interfere with tape bias and cause distortion. This makes them useful when recording from FM tuners.

Full-Scale Stabilized Power Supply

The KX-800’s power supply is a full-scale stabilized circuit. It prevents fluctuations from line noise or load changes, which keeps recording levels and frequency response consistent. Many manufacturers cut corners on power regulation in this era. Here the regulation helps the deck hold up during long recording sessions or where the mains voltage is unstable.

Independent Line and Microphone Input Paths

The input design treats line and microphone signals separately. The line input bypasses the microphone preamp entirely and feeds the recording amplifier directly. External sources such as mixers or turntable preamps therefore skip the extra gain stages that could add noise or coloration. The microphone input is rated at 0.19mV/18kΩ for 600Ω low-impedance mics. It has an ATT switch that attenuates the signal by -12dB to prevent overload on loud sources. This dual-path routing was uncommon in consumer decks of the time.

Timer Standby Mechanism

The KX-800 has a timer standby function, so it can be programmed to power down after a set period of inactivity. This saves energy and reduces wear on internal parts while the deck sits idle, which suits home studio or broadcast use where it might be left on for long stretches. It is not a full auto-off recording timer.

Single-Knob Tape Selector for Bias and EQ

The tape selector switch is a single rotary knob that controls bias, playback equalization, recording equalization, and recording sensitivity together. Its positions are Normal, Ferrichrome, Chrome, and Metal. Each one automatically adjusts all the relevant parameters to match the selected tape formulation. There is no manual bias tweaking and no separate EQ switches, so there are fewer setup errors.

Collectibility & Value

No current market prices or valuation estimates are documented in available sources. User reports say the most common failure point is degraded idler belts, as with many cassette decks of this era. One owner noted receiving a unit with a pre-existing belt issue, which suggests the rubber parts may need replacing after decades of storage. Service and user manuals for the KX-800 are available through vintage electronics resellers, which points to ongoing interest among restorers. Given its 3-head design, the deck remains a candidate for refurbishment, though the lack of a monitor function may limit appeal.