Kenwood Corporation
	Public TYO: 6765
Founded	1946
Headquarters	Hachiōji, Tokyo, Japan
Key people	Haruo Kawahara CEO
Industry	Consumer electronics, electronics
Products	Consumers electronics
Revenue	$1.68 billion USD (2006)[1]
Operating income	n/a
Net income	n/a
Employees	4,424 (2006)
Website	http://www.kenwood.com

Kenwood Corporation (株式会社ケンウッド, Kabushiki-kaisha Kenuddo) (TYO: 6765 ) is a Japanese manufacturer of amateur radio as well as Hi-Fi and portable audio equipment.

History

The company first started in 1946 as the Kasuga Radio Co. Ltd. In Komagane City, Nagano Prefecture, Japan. In 1960 the firm was renamed "Trio Corporation". 1963 saw the foundation of Kenwood USA, the first overseas office of Trio, in Los Angeles, California, USA.

In the early 1960s, The LaFayette Radio Company rebranded and sold Trio's products, unfortunately focusing on the doomed 23-channel CB radio.

Innovation at the company was very significant during this period. Trio built oscilloscopes, such as the popular 10 MHz CS-1562A. Kenwood introduced Japan's first FM tuner and solid state amplifier. The company introduced an amplifier with integrated audio and video signal switching in 1981. This product is seen as a precursor to today's home cinema systems.

In 1984, Kenwood designed and manufactured the first anti-theft car stereo receiver. In 1986, Trio-Kenwood became Kenwood Corporation.

Kenwood introduced its Sovereign line of components in 2001. This high-end line competes with prestige brands of other manufacturers such as Pioneer Elite, Sony ES, Onkyo Integra, and Matsushita Technics. In the car audio market, the "eXcelon" line similarly competes Pioneer Premier and Sony Mobile ES brands.

Notable products and inventions

Amateur Radio Transceivers

Kenwood has offered distinct lines of HF, VHF/UHF, and portable amateur radio models.

Among the product lines, the "TS" series of HF transceivers can be said to be among Kenwood's flagship products. These radios cover the HF ("high frequency") bands, from 1.8 to 30 MHz, and can easily let the user communicate around the world, via voice, CW (Morse), PSK31 or RTTY (digital modes of communication), with output power of around 50-100 Watts. These included:

• TS-800 series -- From the late 1970s, the TS-820 was one of the first Kenwood transceivers to gain widespread acceptance in the Amateur Radio community. The original model included a single VFO (variable frequency oscillator), although a second VFO could be purchased as a stand-alone option; a matching receiver, the R-820, was also available, which permitted split frequency operation. A digital display was another option, available to be retrofit to the original device. With the digital display installed, a TS-820 could be named a "TS-820S": all future Kenwood HF transceivers have used the "S" designation to signify presence of a digital display, though the feature has long since become standard equipment.
• TS-900 series -- From the mid-1980s, the TS-930S and, to a greater extent, the TS-940S represented a step-up in features, size, and cost from the 800-series models. Introduced around 1986, the TS-940S was considered a classic of its time which was later succeeded by the TS-950. It was Kenwood's first model to permit the HF transceiver to be fully controlled by a personal computer (via RS-232 cable and an aftermarket interface, the IF-232). In later years, this became standard equipment on almost all serious HF radios, and some radios would drop the human interface features entirely, being controlled entirely by a remote computer.
• TS-400 series -- with models including the TS-430S, TS-440S, TS-450 and TS-480, these units featured a smaller size, were operated on 12 Volts -- meaning batteries could be used -- and were suitable for use as a portable base station, such as during Amateur Radio Field Day.
• TS-600 series -- These models were mainly identical to their 400 series counterparts but offered the 6 Meters band as an addition. For example the TS-450S and the TS-690S have the same exterior and mostly the same specifications on the 1.8-30 MHz HF bands, but adding the 6 Meters band.

Other series include the 100, 500, and the new 2000 series. The TS-2000 is Kenwood's current top of the line model. It includes all-mode operation on HF, 6 meters, 2 meters, 70 centimeters (420 - 450 MHz), and in the "X" model the 23 centimeters band (1.24 - 1.30 GHz). Kenwood also offers a "B" model which is a transceiver without display or controls and is completely controlled by a remote computer or a separate control unit. This allows using it as a mobile transceiver where the main unit is placed in the trunk or an area that provides enough room to house it, possible closer to the antenna, and have a control unit in the front of the car. A setup like this allows the control unit to be placed closer to the driver and the transceiver closer to the antenna which shortens the cable, reducing possible interference.

L-series Product Line

In the late 1970s Trio Kenwood put to use their experience in DC to high-frequency amplification used in oscilloscopes and embarked on what was to become their signature High-end HiFi gear, the famous L-series (or Lab-series). Starting with the L-05, 7 & 9 pre/power amplifiers, the L-07T tuner and the L-07D direct drive turntable. In 1979 they started the New-Separate amplifier series with the L-01A integrated amplifier and matching L-01T tuner. Their biggest statement in High-End audio came in 1982 with the L-02A integrated amplifier and L-02T Tuner. Especially the L-02T is regarded as one of the best tuners ever made. In 1983/4 the L-03A and T where launched, but were aimed primarily on the Japanese market. The first L-series CD-player was the L-03DP which had a front loading mechanism much like a casettedeck. In 1989 the L-1000 series were launched. The L-1000 series consisted of a control amplifier, power amplifier, tuner and CD-player. The last line of the L-series came in 1994 with the L-A1 integrated amplifier and the L-D1 CD-player. Especially the CD-player is famous for its "analogue" sound, unfortunately this last L-series is extremely rare. After 1994 no new L-series have been launched and with the subsequent demise and near bankruptcy of Kenwood in the late 1990s no new L-series will ever be built as they were loss-leaders for Kenwood. Most of the L-series were designed by Kenwood, but manufactured by Kensonic (known today as Accuphase)

Sigma Drive

Kenwood's Sigma Drive has been widely acclaimed as an effective means of providing optimum speaker control and an extremely high damping factor right up to the speaker input terminals. In addition to the normal speaker leads, a special "Sigma" connection feeds distortion products caused in the speaker wires and in the speakers themselves back into the amplifier's NFB loop for effective compensation. The result is a total control over the speaker's behaviour, with optimum damping of unwanted speaker movement. [...] Sigma Drive is also employed between the pre-amp and power-amp stages where it compensates for any signal loss in the interconnection and permits low impedance drive throughout the frequency range.

Dynamic Linear Drive (DLD)

An analysis of the dynamic power demands made by actual music indicates that high power levels are needed usually only for very brief time spans, during short-lived transient energy bursts, and that perhaps ninety to ninety-five percent of the time a low-to-medium power level prevails. But whenever those energy bursts -drumbeats, cymbal crashes, piano attacks- happen along, lots of clean will be needed. What this means is that you actually need two power amps in one: a medium-powered "steady worker" and a high-powered "temporary" help, both of truly audiophile distinction.

This is exactly the basic concept of Kenwood's Dynamic Linear Drive. An ingeniously designed group of circuits downstream of the predriver stage monitors the signal flow and determines, instantly, whether or not the power demand exceeds that of the medium power-stage. Whenever it does, the signal is assigned to the high-power stage which gladly obliges by delivering the brief energy peak needed. This monitoring, decision-making and "assigning" is performed by circuits using transistors that operate in the gigahertz range, the most advanced of all modern semiconductors.

The DLD concept must not, however, be confused with other manufacturers' previous attempts at providing high power through various means. It is not a simple booster following the normal power stages ; it is not a series-connected high-voltage stage switched in temporarily and built with little regards to sonic quality. It is a high-powered, high-quality amp, operating in parallel to the normal power stage, built to handle all energy peaks with extremely low distortion.

D.R.I.V.E.

DRIVE stands for Dynamic Resolution Intensive Vector Enhancement. This IC invented in the early 1990s, hugely enhances soft signals in CD-players by interpreting the signal and then relaying it through various filters in order to recreate as close as possible the signal as it was recorded. Many improvements were released with new versions of the DRIVE IC's.

T.R.A.I.T.

TRAIT stands for Thermally Reactive Advanced Instantaneous Transistor. This means that the thermocouple necessary to compensate for temperature effects in power transistors is housed inside the transistor instead of the traditional place on the heatsink. This minimizes the time difference between actual temperature of the transistor and measured temperature on the heatsink. This improves the sound quality of the amplified signal. TRAIT transistors have 5 pins instead of the normal 3 (Base, Collector, Emitter or Gate, Source, Drain for MOSFET's) TRAIT transistors, manufactured by Sanken Electronics, were used in the mid 1990s for the first time in Kenwood amplifiers. TRAIT is called K-Stat in the USA.

TrueX Optical Drives

In 1998, Kenwood released the TrueX line of personal computer CD-ROM drives, first at the speed of 40x, then 52x and 72x. The TrueX CD-ROM drives use a low rotational speed (approximately 6x to 10x) with seven laser pickups functioning in parallel to read data at faster overall speeds.

References

External links

• Kenwood Global site
• Kenwood Electronics Europe
• Company Timeline
• Kenwood L-09M Exhibit at The High Fidelity Museum