Behind The Scenes (Oct. 1977)

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Last month, I pointed out that the 1977 Summer Consumer Electronic Show in Chicago was the biggest and most comprehensive ever...so much so that I couldn't finish my report in one column. So without further ado ... I will continue my survey.

I hadn't quite finished my roundup of interesting power amplifiers...so here are a few more... RAM Audio Systems of Danbury, Conn., was demonstrating their Model 512, rated at 180 watts/channel into 8 ohms. The unit features minimum negative feedback (27 dB), low phase shift, a propagation delay of less than 0.2 microseconds, overload recovery of less than a microsecond from a level of 10 dB over clipping, and is priced at $1100.00. Soundcraftsmen had a new MA-5002 250 watt/channel/8 ohm amplifier utilizing a dual power supply, which they have named Vari-Portional and have a patent pending.

One power supply voltage is two-thirds of the larger one, which only functions when the output level reaches the voltage limit of the first supply stage. The advantages of this scheme are lower power consumption and less heat dissipation than with a conventional AB amp of the same output capability. Pioneer was showing the production version of their M22 Class-A, 30W/chan amplifier on which I have reported previously. From Harman Kardon comes the Citation 19, another of those power amplifiers built on the Otala/Curl concepts for low TIM. Power output is 100 watts/channel, and it can be bridged to 350 watts/ch.

At the $495.00 price, two of the units in the 350-watt mode cost less than a thousand dollars ... a lot of watts for the money. Sony was showing its small, slim 150 watts/channel Class D switching amplifier, now slated for Fall delivery. Infinity, first on the market with Class-D amplifiers, was demonstrating their new 350 watts/channel unit. Here again, quite a small package for the high output.

Before I close this section, there is a new company, A&E Technical Research, which was showing what they call their Model E-2000 equalizing preamplifier. The unit features RIAA phono curve accuracy within ±0.2 dB, six selectable phono input impedances, and claims only 0 to 3 degrees phase shift across the entire 20 Hz to 20 kHz range, and a group time delay of only 0.7 microseconds.

Tape Decks

Tape equipment was well represented at the Show. As you might expect, cassette decks dominated the scene, but there were strong showings of high-end open-reel equipment from the usual specialty sources...Teac, Revox, Tandberg, etc., and surprising new entries from Pioneer, the RT-701 and RT-707 tape decks. Take a quick look at them, and you'll do a double-take for they hearken right back to the good old days, looking very much like the famous old Magnecord PT-6 series of recorders. Made for rack mounting, they are 19 inches wide by 9 inches in height and can accept up to seveninch reels. Both models use a.c.-servo direct-drive capstan motors, and two inner rotor induction motors for reel drive. The RT-701 has three permalloy heads and the RT-707 has four heads, the extra head being for automatic reverse play. This is especially significant now that we are having a renaissance of open-reel prerecorded tape. Stereotape is now issuing music from the RCA, London and DGG catalogs, while Barclay-Crocker is out with material from Vanguard, Musical Heritage, Desmar, Halcyon, and other catalogs. Tape reversal is accomplished via the foil strip method, and the unit has a repeat mode as well.

Both decks are replete with the usual goodies, like logic controlled motion switching, two position bias and EQ switches, pause, and pitch control.

Frequency response is ± 3 dB, 30 to 24,000 Hz @ 7 1/2 ips, wow and flutter 0.05 W RMS @ 7 1/2 ips S/N ratio is better than 58 dB. The Uher " Omega Drive" (no pinch roller) open-reel deck has undergone some revisions and is expected to be introduced this Fall.

Pioneer also had an interesting new cassette deck, the model CT-F1000.

This is a two-motor, closed-loop, dual capstan tape drive, with three single crystal ferrite heads (a la Ampex ATR100). A dual Dolby circuit permits Dolby recording and Dolby monitoring off the tape. The unit has a two position bias and a three position EQ switch; tape motion is activated by logic-controlled solenoids. There is an automatic sensing system for CrO2 tape. Wow and flutter is claimed to be less than 0.08 percent W RMS, and frequency response is stated to be ± 3 dB from 30 to 17,000 Hz with CrO2 tape. Most remarkably, the S/N ratio is said to be 69-70 dB with Dolby on and using CrO2 tape. Nakamichi was on hand with the Mark II versions of their three-head models 1000 and 700. These cassette units and all Nakamichi two-head machines are fitted with their new crystal permalloy "Superheads" with 1.5-mil gaps and a specially configured head face. The result is a claimed head life of over 10,000 hours before replacement is necessary. In the same rarified atmosphere of the Nakamichi 1000 was the $1600.00 Teac 860 and the $1500.00 Technics RS9900-US on which I have previously reported. Aiwa got a lot of attention with its Model AD-6800,

with such features as three heads, Dolby monitoring, what they call a "Flat Response Tuning System," a built-in 400and 8000-Hz oscillator, with front panel "bias fine tuning" for standard type of tape, and an azimuth alignment system.

The latest Elcaset model at the Show was the JVC Model LD-777, which features solenoid operation, three heads for off-tape monitoring, ANRS noise reduction (if prerecorded Dolby Elcasets become available, inserting the tape automatically selects the decode mode), and Super ANRS as an option. The unit has six LED peak reading indicators, as well as two VU meters, and a 400-Hz and 15-kHz oscillator is furnished for sensitivity and bias adjustments. The unit's suggested retail price is $799.95.

Turntables

Not to be outdone by the tape medium, there was plenty of action in the disk camp with a raft of new turntables, arms and cartridges. Among the most talked about new designs was the Accutrac +6, a changer version of last year's super-automated turntable, the Accutrac 4000. This unit enables you to play any sequence of bands in a total of six records. As with the 4000, remote control of all the automated features is possible, and it goes a step further by remote control of volume. However, in contrast to the direct drive of the 4000, the +6 uses belt drive with an a.c. synchronous 24-pole motor. The +6 also has capacitance "touch" controls instead of pushbuttons. The price of the +6 is $399.95, with several other changer models with fewer features than the +6 at lower prices. Technics was showing new lower-priced direct drive turntables, the automatic SL 1950 at $200.00, the SL-1650 at $300.00, and the SL-1350 at $350.00. They were also showing their very limited edition SL-1000, which consists of the new SP-10 Mark 2 turntable mounted in a magnificent 37-pound mirror polished, black lava rock/epoxy base and their new EPA-100 arm. The arm is the pride of Dr. Obada of the Technics research dept. A group of us were shown this arm and its inner workings last December in Japan. The arm tube is extremely low mass, but very rigid titanium nitride. It has about a third less mass than carbon fiber, and there are 20 high-precision ruby bearings in the pivot assembly. The arm has a unique magnetic viscous silicone damping system for the correction of various arm/cartridge resonances. It works by determining the compliance of a cartridge, and then setting a calibrated dial for the particular compliance. It is all yours for $1300.00. JVC was showing their quartz PLL turntable with its fascinating LED readout of rotational speed. Pioneer has entered the field of quartz PLL turntables with its Model PLC-590. It is sold without an arm, but there are pre-cut mounting plates for Pioneer arms and the SME arm. Blank plates are also available.

You could hardly turn around without running into direct-drive turntables from a large number of Japanese companies.

Thorens was leading the belt-drive contingent with four new models, all featuring the unusual facility of interchangeable arm tubes, rather than cartridge heads. The top of the line TD-126C "Isotrack" table features 33 1/3, 45, and 78 rpm speeds, all pitch adjustable, and a 16-pole synchronous motor, with Wein-Bridge oscillator for motor control. DIN weighted rumble is said to be-70 dB. Infinity was demonstrating their unique Black Widow turntable with an "air-bearing." The main platter has a sub-platter and the pressurized "air bearing" is between these elements.

The highly regarded Infinity "Black Widow" arm is mounted on the turntable, and the combination is priced at $400.00. Of arms, Sumiko was showing their extensive line of Grace arms, including the low-mass G-707 and their new metal frame G940 unipivot arm. Around the Show, quite a few people were using the Dynavector arm. This expensive ($500.00) arm has a main section which pivots only horizontally and a smaller cartridge bearing sub-arm, which pivots only vertically, attached to the end of the main arm section. The Pickering 190 D arm of more than 20 years ago had a somewhat similar idea.

There were quite a few new cartridges at the Show. The Satin moving coil cartridges have been redesigned, and their top Model 118BX features a beryllium cantilever. All the Satin cartridges have user-replaceable stylii and high enough output to obviate the need for transformers or pre-preamps. The Ortofon MC20 moving coil cartridge is the pride of a company long noted for this type of cartridge. Ortofon makes a pre-preamp for this cartridge, but other pre-preamps and transformers can be used. There is a very smooth top end on these cartridges. ADC had their new ZLM cartridge on display, featuring low tip mass, a specially contoured "elliptic" stylus, and very high compliance. Stanton was demonstrating their new 881S calibration standard cartridge. This unit has the Stereohedron stylus introduced on the Pickering 3000, but in this case a special samarium cobalt magnetic assembly is used which gives this cartridge the high output of 0.9 mV/cm/sec. A new patented suspension system is employed, and each cartridge is individually calibrated to 20 kHz. Price is $150.00. The RAM people, who make the previously mentioned amplifiers, also make a phono cartridge system, the 9210SG. This is a semi-conductor strain-gauge unit which mates with the RAM 9210 Power Source-Preamplifier. I didn't hear the system, but the specs are impressive...5 to 20,000 Hz, ± 1 dB. Price is $299.95.

One last item in this section...Sony was showing a prototype turntable, which automatically turns over the record after the first play. Shades of Capehart and 1935! No mention of production, however.

Speaker Systems

Needless to say, there were more loudspeakers on demonstration than one could listen to in 10 days, let alone four! I must freely confess that a great many of these speakers leave me cold. Their stolid "sameness" is stultifying, and the sonic virtues they are touted as having, are conspicuous by their absence. Further, while I am in a curmudgeon-ish mood, most of these speakers are demonstrated by inept people, who choose absolutely execrable program material, and who grin fatuously at you, and say "isn't that great?" and all the while you are hearing this raucous cacaphony and God-awful distortion. One trend that seems to be growing is the attention being given to time delay distortion, or "time smear" if you will. In multiple driver speakers, the drivers are positioned...usually "staggered" on the vertical axis...so that their sound is propagated on the same acoustic plane. In some cases, the crossover network is also "time-compensated," and in still other cases, a combination of acoustic and electronic time compensation is used. There were a number of good examples of this kind of speaker at the Show; Technics had their ST7000 "linear phase" speaker on demonstration, as was Bower and Wilkins' DM6. The KEF 105 is an interesting example of this breed of speaker. A three-way system, the midrange and tweeter are in separate enclosures, which are positioned in the same acoustic plane as the woofer enclosure, but they go a step further, and an LED is mounted in the midrange and tweeter enclosures and is only visible when the speakers and the listener are in optimum listening relation. Both mid-range and tweeter enclosures are manually adjustable in aid of this feature. Another time-delay compensated speaker is the Symdex RST. This is a five-way hybrid loudspeaker, with a 12 in. subwoofer, 10 in. mid-woofer, mid-range, and mid tweeter, all of which are dynamic drivers, and an electrostatic array handles the higher frequencies above 9 kHz. Here too, the drivers are all positioned for a common acoustic plane. This is a big speaker...nearly 4 1/2 feet in height, and cosmetically it reminds one of the Fulton Model J speaker.

Speaking of the Model J, Bob Fulton was proudly demonstrating it as part of what he calls "The Music System." This comprises turntable, arm, cartridge, preamp and amplifier, and the Model J speakers. The equipment is from manufacturers like Shure, Audio Research, and Bravura and has been modified by Bob Fulton to the particular requirements of his system. He was feeling good because his "Music System" had been chosen by The Stereophile magazine as the "state-of-the-art" system. It certainly was one of the best sounding systems at the Show, with a smooth well-balanced spectrum which did justice to Bob's own fine recordings.

JBL was demonstrating what was for them a radical departure from the type of speakers they have been producing over the years...the model L212. This consists of two panels roughly 4 in. in depth, each containing a three-way speaker system.

The reason for the shallow depth is that at 70 Hz, they crossover to a common bass commode. This commode has its own 50-watt amplifier and equalizer. Since frequencies of 70 Hz and below are non-directional, the "Ultrabass" as JBL calls it, can be placed almost anywhere in a listening room (and no doubt to the delight of the ladies, hidden from sight), which allows this system great flexibility.

Although in their advertising the panels look almost monolithic, actually with their integral stands they are only about 38 inches in height. Quite efficient, the whole system puts out a very big sound. Price is $1740.00. You can always trust Gene Czerwinski of Cerwin-Vega to come up with something different. Gene has this new S1LS2 three-way speaker system that has what he calls a "thermo vapor suspension." Huh? It seems Gene has discovered a very heavy inert gas, much heavier than air, which he places in a sealed plastic bag and places in the speaker enclosure.

Because the acoustic impedance of the gas inside the box is greater than with air, it lowers the box compliance and aids in damping and loading the speaker cone for better bass response.

As usual, Gene's speakers can "out punch" practically anything, but he was very conservative this year.

Best sound at the Show? The honor has to go to Mark Levinson's HQD System. This consists of two Hartley 24-inch woofers in specially made 4x3x2-foot enclosures, stacked pairs of Quad electrostatic speaker panels in special frames built for this stacking, and two Decca ribbon tweeters.

All this is driven by either Levinson ML-1 or LNP-2 preamplifiers, two LNC-2 electronic crossovers, a pair of the Levinson ML-2 Class-A amplifiers for the woofers, another pair of ML-2 for the mid-range, and still another pair for the tweeters. Crossover points are at 100 Hz and 7 kHz. The result with the very best program material is a sound of utter cleanness, of crystal transparency, razor sharp transient response, and solid, well-defined bass, a totally natural sound that is absolutely non-fatiguing. A stellar accomplishment, and a product for those who are totally committed to music and have the means to afford such a system.

Auto Hi Fi

Now for some special items. ..to Dr. Godehard Guenther of ADS must be accorded a hearty round of applause for one of the most sensational items at the Show...the ADS Compu-Tuner, a car tuner/preamplifier. This tiny unit (2 in. high by 7 in. wide by 61/2 in. deep) is one of the most sophisticated products in all of audio. The Compu-Tuner is a micro computer-based FM/AM digital tuner-preamplifier for automotive high fidelity installations (it can be used in the home as well). This tiny system has no moving mechanical parts and employs calculator type keys for all functions, such as volume, tuning, tone control, source selection, store, recall, and others. The CompuTuner can electronically store up to 20 FM stereo and AM stations. A large four-digit LED readout displays operating modes, FM or AM frequency, memory locations, and auxiliary messages. The unit has a crystal controlled frequency synthesizer. It contains a central processor unit which executes all instructions called for by its pre-programmed read-only memory (ROM) and those entered through the tuner keyboard to the random access memory (RAM). Stored stations can be recalled at the touch of one key. Automatic scan, memory scan, and direct frequency keyboard entry of the desired station are possible for both AM and FM. The Compu-Tuner has a high quality preamplifier with a digital 2-dB stepped electronic volume control, which has a dynamic range of 82 dB. Digitally controlled contouring and filter circuits are also provided. The preamplifier has sufficient signal to drive ADS amplified loudspeakers and can also be interfaced with regular booster amplifiers. With all this fancy control functions, the Compu-Tuner has a full complement of all the goodies found in full size tuners, such as FM front end with dual-gate MOSFET input stage, a balanced IC mixer, and electronically tuned r.f. sections. The i.f. strip utilizes two IC limiters and cascaded phase-linear ceramic filters. A balanced quadrature detector and a phase-lock-loop decoder are utilized. Clearly, this unique ADS Compu-Tuner indicates the direction in which digital technology is moving and is a foretaste of new revolutions to come.

Sony showed its Betamax video tape recorder with the pulse code modulation adaptor, but I was never in the room with anyone who could demonstrate the unit. Videotape looms large in the future, as evidenced by the appearance of more recorders. JVC introduced its Vidstar, a unit with two-hour recording capability that elicited much favorable comment.

Philips/Magnavox announced they would be using Matsushita VHS system video recorder with its four-hour recording capacity. RCA opted for the same unit.

Elcasets were shown by Teac, Technics, and Sony, and things may start moving in this format since Sony has decided to license other companies to make the tape on a license-free basis.

Lastly, quadraphonics remains moribund, but everyone is eagerly awaiting the outcome of the FCC tests. JVC has the fine new noise-gate CD-4 demodulator, which does a great job on even some of the older CD-4 records. The unit can be purchased through the JVC cutting center in Los Angeles. Sansui still flys the flag with some quadraphonic receivers. Tate has their SQ chips in production as I related to you in my AES report. At the Show they were demonstrating the synthesizer function of their unit, and the results were very fine indeed with a wide range of program material.

That wraps up the summer CES for this year, and as usual, there were far more pieces of interesting gear than we can possibly cover.

(Source: Audio magazine, Oct. 1977; Bert Whyte)

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