Introduction

 

In the late 1970's and early 1980's, Japanese turntable development had reached new levels of engineering excellence and sound performance.  The major manufacturers competed for top honors with flagship efforts that were known as their "Statement" models.  These flagship models were the manufacturer's "statement" about their engineering philosophies and production capabilities.  Each manufacturer tried to outdo the other.  Players at the time included Denon, Kenwood, Luxman, Micro Seiki, Nakamichi, Sony and Technics.  An excellent website to learn more about the other players in this competition is the "Direct Drive Museum" website.  This website is dedicated to Kenwood's Statement player, the L-07D.

In the late 1970's, the Kenwood-Trio Corporation of Japan sought to enhance their image as a developer and manufacturer of high end audiophile gear.  The result was a line-up of high end components known as the "L-Series".   Kenwood was able to show the world that it had a superb ability to understand the audiophile's needs for affordable products with extremely accurate sonic performance.  The main issue that needed to be overcome was that production of a "no compromises" series of audiophile components would be prohibitively expensive.  The decision was made, probably for marketing reasons, to design and produce a no-compromises series of "Audio-Purist" high-end audiophile components.   These were "loss leader" items, designed to showcase the capabilities of Kenwood in many ways.  This would show the world what Kenwood could and would do.  I doubt that Kenwood ever made a dime in return on the L-series.  Some of their efforts stood the audiophile world on-end.  Nowadays, Kenwood is a hugely successful international electronics giant.  Did the L-series gain Kenwood the international respect and recognition they sought at the time?  You be the judge.

The name L-07D is derived from several individual abbreviations.  The "L-" portion of the model name signifies that this was part of the elite Laboratory Series of components.  The L-07D is the only turntable ever made that was worthy of inclusion in the L-Series.  The "07" portion of the model name signifies the design team.   The name, "L-07" came about because Kenwood had assembled a "Delta Force" of their very top engineers, the "Team of Experts".  There were seven experts, hence the name.  Their mission was to design a series of audio components with absolutely no cost constraints whatsoever - just push the envelope as hard as it could be pushed.  Thus was laid the impetus for the birth of the incredible L-07D turntable.  In the competition of the day, it was a knockout.  A lot of what the "Team of Experts" did has trickled down to their less expensive components of that era, and beyond.  Finally, the "D" portion was the letter assigned to the turntable.  "C" was assigned to the preamp models, "M" was assigned to the amplifier models, and "T" was assigned to the tuner models. 

In the U.K. at the time, another entity with the Kenwood name prevented the Kenwood-Trio Corporation from marketing their products under the Kenwood name.  Instead, they marketed their products under the brand name "Trio".  The name "Trio" is believed to be derived from Kenwood's logo symbol, which is a stick-figure tree in a circle.  (Tree + Circle = Tree + O = Tree O = Trio).  All L-07D's sold in the U.K. were badged as Trio L-07D's.  Everywhere else, they were badged as Kenwood L-07D's.

According to the L-07D brochure, the design philosophy of the L-07D was "Nothing less than 100% conversion of recorded to reproduced music signals".  In doing so, Kenwood's "Team of Experts" literally redesigned the turntable. 

According to the instruction manual, The L-07D was designed giving priority to the following:

  1. High rigidity and good anti-vibration properties.

  2. The three supporting points in the pickup loop are extremely accurate.

  3. High transient load characteristics.

  4. High fidelity electrical signal transmission.

The L-07D engineering team used the concept of extreme rigidity to attack the problem of undesirable vibrational movement affecting the point of contact between the cantilevered stylus and the record groove.  This was accomplished by laminating different materials to cancel out inherent resonant frequencies, and designing the entire signal conversion system into an ultra-rigid closed loop.  A vibration proof laminate platter was used to eliminate platter resonances. A drive system with extremely high moment of inertia was used to deal with transient load effects of varying stylus drag.  The motor is kept at either a perfect 33.33 or 45 rpm by means of a crystal-controlled frequency generator.  The crystal vibrates at a constant 5.5296 MHz.  This frequency will never vary with wall voltage or ambient conditions.  Frequency dividing circuitry in the Control Unit divides the perfectly stable crystal frequency down to a much lower, but still perfectly stable, frequency to drive the high-torque coreless/slotless/brushless DC motor.  With a standard 3150 Hz test tone record, my digital frequency meter reads exactly 3150 Hz.  There is zero tolerance for speed error in this deck.  The constant perfect speed regulation design also contributes to the neutrality of the deck's sound.  In addition, high quality Litz wiring is used throughout the signal transmission chain.

The result is that you hear all of the sonic information on the record, and not the turntable.  The sound of the L-07D is perfectly neutral.  This deck does not impart a sonic signature of its own to the music.

Every part of this deck is perfectly integrated with every other to achieve Kenwood's lofty goals, as stated in the brochure.  And achieve those goals, they did.....


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