The Summer Consumer Electronics Show made its annual stand in Chicago June
15 to 18, and the reception afforded it by the attendees was about the same
as the weather in Chicago ... cool. Long considered the premier showcase of
the industry and a bellwether of its economic health, the mood at the SCES
was somber and subdued, a reflection of the recession which afflicts our country.
Oh, there were some brave noises from the hierarchy of the CES about "record registration," but advance registrations by mail do not necessarily mean warm bodies at the Show. There was no question whatever that traffic was light, and some industry wags said you could throw a bowling ball down the aisles at McCormick Place without hitting anyone. An exaggeration, of course, but dealer attendance was down and there were fewer representatives from the larger retail organizations. Most were playing things close to the vest and being very selective and restrictive in their buying. Ironically, in the midst of all this depressing scene, some manufacturers with interesting new products to show, exulted that this was their "best Show ever." (Editor's Note: While I do agree with friend Bert about attendance, the large majority of the makers and distributors with whom I spoke indicated that they wrote good business at the show. My feeling is the attendance level was indicative of some further belt-tightening over the previous six months to a year--that instead of six fellows from a store coming to the CES, just the chief buyer showed up.--E.P.) In an industry that has never known a deep recession until now, some organizations are obviously coping better than others with the realities of the present situation. The sad thing about this low-key SCES is that in spite of some great expenditures of energy and money, the results were generally disappointing. Believe me, the exhibits were as glittering and glamorous and as well executed as ever. To say there was a plethora of products is a gross understatement. There were unending vistas of them and, as usual, far more than even the most dedicated reporter could possibly cover. There were many comments that this SCES was heavily video oriented (see my "Video Scenes" report), but there was also a staggering array of audio equipment. As usual, the more exotic audio equipment was to be found in the Pick-Congress, McCormick Inn, and a few other hotels. As has been my practice for the past several years, I will not attempt a "shotgun" coverage, but rather a selective report on those audio products which I feel are interesting and can make a contribution towards the realistic reproduction of music.
As far as I am concerned, one of the most exciting new products at the Show was the Lux PD-555 turntable, which has a design feature I have for years been hoping would be incorporated into a consumer turntable. As I am sure you are aware, when a lacquer is cut on a recording lathe, it is held tightly in place on the lathe platter by means of a vacuum "chuck." The lathe platter has a series of concentric channels machined into its surface, with tiny holes in the channels directly connected to a vacuum pump. When the pump evacuates air from the channels, a vacuum is created and the lacquer is "sucked" tightly onto the platter. The Lux PD-555 operates on the same principle. The platter is an 18-pound aluminum die casting, with a sort of bell chamber on the underside of the platter. On the top perimeter and the "label" areas of the platter are two seal rings, with two air holes connected to the bell chamber and thence to a vacuum pump. With our present low-weight, thin-profile phonograph records, those infuriating dish and pinch warps are the rule rather than the exception. When these pesky discs are placed on the platter of this Lux turn table and the vacuum switched on, the air is evacuated between the seal rings and the warps are eliminated as the disc is sucked tightly to the platter.
I tried to remove the disc from the turntable with the vacuum on, and even using considerable force, it is al most impossible to do so. Playback of flat discs removes a number of distortions, not the least of which is warp-wow induced low frequency overload.
A considerable bonus is the virtually complete damping of vinyl resonances. Under vacuum, when the disc was sharply struck, there was a most satisfying non-resonant "thunk." The Lux PD-555 is a belt-driven unit using a brushless, slotless d.c. servo motor.
All the operating components are in a heavy, diecast aluminum frame, heavily insulated to prevent acoustic feed back. This unit is a three-speed turn table and has provisions for mounting two tonearms. The vacuum pump sup plied can provide up to 20 cm Hg pres sure, twice what is needed for operation of the vacuum chuck. A vacuum pressure meter is mounted on the turntable base, and I found the operating pump virtually inaudible. A major development, this Lux PD-555 turn table, with the only rub being the $2800.00 price, but I would speculate that this technology will ultimately be found on lower priced units. In the meanwhile, I can hardly wait for a hands-on experience with this fascinating new turntable.
--- Stylus Tip, Marovskis MIT-1
Staying with the utilization of air, the Dennesen ABLT-1 air-bearing, linear-tracking tonearm might just well be the ideal arm for the Lux PD-555 turntable. Dennesen was showing the first production models of this arm, and a beautiful sight they were, plated with 24-karat gold. As I have described previously, an air pump supplies a stream of air which impinges on an "air foil" connected to a skeletal arm structure, causing the arm to "hover" on a frictionless air bearing above the air-bearing assembly tube. The air bearing allows frictionless lateral trans it of the arm across the record and eliminates some audible resonances. A built-in micrometer permits dynamic adjustment of the vertical tracking angle, and a damped cueing system raises and lowers the arm. With the elimination of significant resonances and having zero tracking error, one can hear the result of changes in VTA much more easily than with conventional arms. A clever idea, well executed, and I hope to mate one of these arms with the Lux PD-555 in the not too distant future.
----- Luxman PD-555
Many people keep talking about how true digital disc recordings will finally make the venerable phonograph record obsolete. Quite possibly true, but that day is far distant in the future, and for a threatened technology, there is a great deal of activity in the field.
Witness the two reports above, and there are quite a few other new developments. For example, John Marovskis (of Janis sub-woofer fame) has introduced a new moving-coil cartridge with a radical new playback stylus configuration. This stylus is the patented invention of A. J. van den Hull of Holland, and with its constant contact radius looks frighteningly like a typical cutting stylus! Rest assured it doesn't cut your precious recordings, but with the same critical dimensions and pro file of a cutting stylus, it compensates for errors in the geometry of the cutting system and the resilience of the recording and playback media. Be cause of this, John has named his cartridge the Mirror Image Transducer MIT-1. The cartridge itself was especially designed to complement the ad vantages of the new stylus profile.
Very flat 20 Hz to 20 kHz response is claimed as is an altogether remarkable channel separation of 40 dB at 1 kHz.
The mirror image nature of the stylus profile is said to give dramatically improved dynamic phase characteristics, with subsequent focus and stereo image stability, and superior tracing of high-frequency transients. Inner groove distortions are said to be non existent in playback with this new stylus. Price of the MIT-1 is $550.00.
Micro-Acoustics has a new group of Series Two cartridges which they claim are the "fastest" in the industry, utilizing hair-thin beryllium cantilevers and styli with very low tip mass. Stanton has introduced their 980 LZS and Pickering their XLZ-750. Both cartridges are quite a departure for these firms, being moving magnet cartridges, but with an extremely low 0.2 mV output, which require pre-preamps or transformers to step up voltage as with moving-coil designs. Both cartridges have samarium-cobalt magnets, an effective tip mass of only 0.2 mg, very low 1-mH inductance. The rise time quoted is a very fast 10 microseconds, and they are said to track velocities as high as 100 microns.
Sony has taken the plunge into moving-coil cartridges, with their top-of-the-line model featuring a diamond cantilever a la Dynavector. Bob Fulton has a new high-precision arm with special bearings, and it uses Fulton headshell wire throughout the length of the arm. No interchangeable headshells on this arm. Dave Fletcher of Sumiko, importer of Supex and Koetsu cartridges, has now put The Arm into production and is said to have bearings even more precise than the vaunted Breuer from Switzerland. Price has been finalized at a somewhat breath taking $1250.00.
Besides the radical Lux PD-555, there were other interesting new turntables at the SCES. Lateral tracking turntables are "in" now, with models from Yamaha and Aiwa (I've not seen these), the diminutive Technics discussed some months ago, the new Mitsubishi LT-30, and the up-dated Phase Linear 8000 Series Two. The Phase Linear unit's big feature is the direct-induction linear motor for the arm assembly. Essentially the arm base has a permanently magnetized armature driven by an electro-magnetic coil. Thus there are no mechanical linkages, gears, belts, etc. between arm and linear-drive motor. When a cur rent is applied to the coil, the tonearm assembly glides along guide rails underneath. An opto-electronic sensor detects any tracking errors (as little as 0.2 degrees is claimed) and sends corrective signals to the differential amplifier that powers the drive coils.
Phase Linear states that this type of linear-tracking arm permits badly warped and off-center records to be tracked. The turntable employs a stable hanging-rotor d.c. motor in which the motor shaft does not rotate.
Unlike most turntables, the main bearing is above a fixed motorshaft at the center of gravity of the rotating assembly. Phase Linear maintains that this system enables a wow and flutter figure of 0.013 percent W rms, lowest in the industry. The rumble spec is quoted at -78 dB (DIN B). The Mitsubishi LT-30 is another linear-tracking turn table. Their philosophy differs from Phase Linear in that they have a fairly massive arm assembly (almost three pounds) driven by a servo-motor with optical sensors, coupled with a worm reduction gear and a nylon-covered stainless wire to activate the arm assembly which rides on stainless steel rods and sintered metal bearings. They claim this is a better system than free arm assemblies which can have "objectionable slippage." Mitsubishi incorporates their own LSI microprocessor chip which permits automatic control of record size, lead-in, auto cue and lift, auto repeat, and other functions including stylus protection in the form of an arm "lock" which prevents the arm from descending if no record is on the turntable platter.
Linn Sondek now offers their own complete disc playback system consisting of the LP12 turntable, the new Linn lttok-LV-11 pickup arm, Linn Asak moving-coil cartridge, and Linn moving-coil pre-preamplifier. Linn's philosophy can be summed up easily:
Spurious resonances are the "arch-enemy" of high-quality record reproduction. Their goal is to eliminate or damp resonances wherever they occur in the record playback system. This design aspect of their LP12 turntable is quite well known. The new Ittok arm carries on in a similar vein, with thin-walled but large-diameter magnesium arm tube and magnesium non-inter changeable headshell. The bearings, bearing housings, arm pillar and all related parts are made of stainless steel, thus all have the same coefficient of expansion, so that temperature changes in a room will affect all these parts equally. The steel shaft of the arm has a special locking mechanism which couples it rigidly with the turn table base. Similarly, the Asak cartridge has an unusually wide body of especially high strength and recessed cartridge mounting holes, so that no screw slippage can occur. Here again, the idea is to rigidly couple the cartridge to the headshell. The importance of ultra-tight coupling of arm and cartridges for the damping of resonances has been documented in studies by Poul Laadegaard of Bruel and Kjaer in Denmark. There apparently is much merit in this idea, and the new Linn system appears to be a well-executed reflection of this design philosophy.
-------- Thorens Reference turntable
Apparently Audionics of Oregon is also in the anti-resonance camp of turntable design. Heretofore known for their pre-amps, amplifiers, and such exotica as their Space and Image Composer with Tate SQ decoder, they have introduced their first turntable, the LK-1. For innovative use of new materials in turntable design, this Audionics unit is a premier example. The turntable platter is made of a special high-density urethane, which is acoustically inert with no ringing modes, and an anti-static agent has been incorporated in the urethane com pound. The turntable base and dust cover are made of a dense silica/epoxy compound, also containing the anti static agent. Audionics states that with the dust cover in place, the density of the cover, base and platter and their inert nature creates a "damped acoustical chamber" for the phonograph record. The platter shaft is ground and honed surgical steel. The platter is belt-driven from a Pabst, outer-rotor, Hall-effect motor with d.c. servo-control and PLL. The motor is independently suspended, and the turntable base is on a unique three-point suspension system with a 3-Hz spring rate. The turntable base, dust cover, and platter are dimensionally stable over a wide range of temperatures.
The whole thrust of this LK-1 turntable is to create a stable platform for the phono cartridge, free from the resonances usually generated by most conventional turntables. The price of the unit is $697.00.
At the opposite poles of turntable design from the Linn and Audionics units are the Sony PS-X75 and the JVC QL-Y5F. The Sony unit has all the usual features now associated with high-
quality Japanese turntables ... direct-drive motor with their Magnedisc servo speed control and automatic control function, but in addition features their micro-processor-controlled Biotracer arm. The arm employs a sensor system with correcting servo motors that "monitors" the conditions of playback, including such things as off-center records and various warps.
Tracking force and anti-skate are under dynamic control, and the system is claimed to attenuate spurious arm/ cartridge resonances. The JVC turn table has their Electro-Dynamic Servo tonearm. Two coreless linear motors are used in the ED Servo arm. Each motor has a velocity detection coil and a drive coil. One servo controls the arm's vertical position, the other motor controls the horizontal position. Here too there is positive tracking of off-center and warped records, while tracking and anti-skating forces are dynamically controlled by continuously variable mechanisms. Low-frequency resonances are damped through the servo-monitoring system, and both air borne and floor-borne vibration and feedback are also damped. As you might expect, this is a direct-drive turntable with what JVC calls their Double Servo quartz control system and coreless d.c. servo motor. Thus the Sony and JVC turntables wage their anti-resonance battles through the agency of their very sophisticated servo arm systems, while the Linn and Audionics turntables use more basic methods. If all these turntables man age to control the very real problem of spurious resonances during record playback, how this is accomplished is purely academic.
One other highly interesting unit was shown a couple of weeks earlier by Thorens, which is now being distributed in the United States by the Epicure organization. This was the Reference turntable, on which engineers were said to have been given carte blanche to "design the finest turntable modern technology would permit without concern for cost." Well now, what does such a turntable have to set it apart, other than its cost which, by the way, friends, is $15,000.00? For one thing, rather extraordinary performance is claimed for the unit, including wow and flutter of less than 0.02 per cent DIN and rumble of less than-84 DIN B (which, incidentally, was measured via the Thorens rumble measuring device). A specially damped, 14 1/2-pound platter is driven by an electronically controlled synchronous motor.
To help conquer various types of feed back, each corner of the turntable has a gold-plated suspension housing which is adjustable to set the resonance of the iron-filled, cast-aluminum chassis anywhere from 1 to 5 Hz.
The Thorens Reference turntable is available only on special order and there is a 3 to 6 month delivery schedule.
Obviously, I've managed to fill a column with new developments in the technology of phonograph record playback. The analog phonograph record may be feeling the first faint tendrils of senility, but it's not ready for the digital gravediggers yet! Next month, I'll cover interesting developments in amplifiers, speakers, and tape decks at the SCES.
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(Source: Audio magazine, Sept. 1980; Bert Whyte)
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