Originally published in the October 1981 issue of Gramophone.

When a turntable unit is as tiny as this Technics SL-7, and yet has so many features and claims such a high standard of performance, one's first reactions are of scepticism bordering on disbelief. The miniaturisation is not just a gimmick, however. Many people will be attracted by a record deck which occupies an absolute minimum of space. As the photograph shows, the total top area is only 315mm square—about the size of an LP record sleeve. When closed, the unit is only 88mm high, and the transparent top pops open to 60° for normal record loading and removal-90° for stylus inspection and cleaning.

All controls are in front of the cover and so are accessible in the closed condition. Operation is automatic and extremely versatile. The presskeys, from left to right, are as follows: cabinet lock/unlock, power on/off, repeat play (giving repeated playing of a record from beginning to end until cancelled), cueing raise/lower (to interrupt play when required, and introducing a muting circuit to cut out needle noise as the stylus meets and leaves the record), start (pressed momentarily to initiate the auto-start cycle, or held down to advance the pickup to any desired starting position over the record: pressing down harder gives a faster search speed), stop (pressed momentarily to initiate the auto-stop cycle, or held down to give a two-speed backwards search mode). If an inching search mode is required at any time, the cue button is first pressed to raise the pickup and then the start and stop buttons can be pressed intermittently to inch the pickup forward or back as necessary.

From the day-to-day operating point of view, that is all there is to know. Putting on records is child's play, and even the comprehensive cue and search functions are beautifully simple and foolproof in action. Speed selection is automatic, three slits in the platter mat enable an optical sensor mechanism to identify the diameter of a record placed on the unit-18, 25 or 30cm—and select 45rpm for the first or 33i-rpm for the others. To over-ride this automatic speed selection, perhaps to play an occasional 30cm/45rpm or 18cm/33rpm disc, there is a manual selector switch, just inside the lid area. The switch has three positions (33+, auto and 45) and will normally be left in the auto position. For safety reasons, the pickup will not lower on to the platter if there is no record on the turntable. To play transparent records, there is a disc size selector switch on the underside of the lid.

As may be guessed, all this ease of operation has been obtained at the expense of quite complicated control gear, and the wonder is that so much advanced technology has been packed into such a small space. Part of the secret lies in the clever direct-drive motor. This combines the rotor and platter in a single piece, and the quartz oscillator controlled drive needs only electronic switching to change speed, and hold the speed accurately under different mains voltage or physical load conditions. Incidentally, the SL-7 can also be run from 120 volts DC, e.g. a car battery, as well as AC mains.

Another feature contributing to the operational ease and minimal dimensions of this turntable is the linear-tracking arm. This adds almost nothing to the area required, unlike the conventional pivoted arm, and indeed is only 105mm (4 inches) long. A coreless DC motor is used to drive the arm along its low-friction slide bearing, in the play and auto return and search modes. The arm is dynamically balanced on a gimbal suspension, tracking force being applied by a spring so that the deck can be used at any angle including the vertical. Opto-electric sensing near the stylus controls the motor drive to keep the arm tangential to the groove, and a tracking angle error of no more than 0.1% is claimed. This of course is the principal reason for the increasing move towards linear tracking in many modern turntables. When the mechanics of straight-line tracking are solved properly, it must certainly be regarded as beneficial since end-of-side distortion and the need for sidethrust (anti-skating) compensation are eliminated.

The cartridge fitted is the Technics EPCP202C moving-magnet which has a samarium cobalt magnet, boron pipe cantilever, and an elliptical diamond stylus. A four-pin push-on fitting is used, which keeps mass to a minimum, and the emergence of a family of these linear tracking turntables from Technics has encouraged a number of top cartridge manufacturers to market special versions of their own designs to fit the Technics units—including Shure, Ortofon and Audio-Technica. Having brought the Shure version, the V I5LT, back from my recent trip to the USA, I have taken the opportunity to run tests using this cartridge on the SL-7 as well as the standard Technics EPC-P202C.

Tracking force is normally 1.25g, which is recommended for the cartridge supplied, but a screwdriver adjustment of +0-25g is easily carried out. Similarly, changing the stylus or the whole cartridge is quite easily performed follow ing the extremely clear illustrated instructions. Closing the lid brings a stabiliser pad down on to the record spindle and label area, and incidentally provides quite a good barrier against the ingress of dust during playing. The stabiliser also carries stroboscope markings which are illuminated by a red lamp synchronised with the quartz oscillator frequency to give a stationary pattern if rotation is in accordance with the selected 33* or 45rpm speed. No fine speed adjustment is provided. Generous lengthed phono-plug leads and two-wire mains cable are attached and the accessories include a screwdriver and stylus brush.

How it performed

The claimed arm/cartridge resonance frequency is I 2Hz, but my tests would suggest more like 8-5Hz for the review sample. This tells us that either the effective arm/cartridge mass or the cartridge compliance is higher than the specified value. However, the frequency as measured still falls within the 8-15Hz range usually recommended as preserving a reasonable compromise between too low a frequency (when record warps could become a problem) and too high a frequency (when the audible range begins).

Specification test results

The 1 kHz square-wave response is fairly flattopped except for a small degree of ringing on the leading edge. This could be a contributing factor to the slightly bright tone I mentioned earlier.

As a test on the potential ability of this Technics deck to operate with other cartridges, and at the same time to assess which aspects of the performance were possibly limited by the given cartridge, I replaced the Technics EPCP202C with the Shure V15LT. Now this is a little unfair, when I tell you that the projected retail price for this Shure model in the UK is £109.25 — more than half that of the complete Technics deck.

As for the turntable itself, this ran with absolutely zero mechanical noise. Rumble too was so low as to be ignored completely, and wow-and-flutter was inaudible. These results are surely a vindication of the unusual design features of this unit—the direct-drive and extremely short linear tracking arm. They are clearly not just gimmicky ways of producing a record deck of minimal proportions—they actually work, and have been superbly engineered and assembled. The automatic start, stop and search-cue functions were a joy to use, and actually kinder to the record than most people's manual operation would be. Since the tightly fitting lid must be closed before and during playing, there is the added bonus of screening from dust. I did notice, however, that the interior warmed up after a time, so that static charges on discs were aggravated.

At the same time, while the dictum "small is beautiful" cannot be applied universally, it does seem appropriate here. The silver and grey finish and uncluttered styling—plus the amazing compactness—must surely attract favourable comment from anyone with eyes to see. Shockproofing against bangs or acoustic feedback was reasonable, helped by the non-resonant diecast cabinet, though a strong shelf or table is recommended. Electrical muting is very useful since it avoids loud plops when the stylus meets the record surface. However I did find one or two records where the music started so soon after the run-in groove as to catch out the muting time span.

The engineering, appearance and delightful automatic operation of this unusual turntable make it a firm recommendation. The wonder is that the price including the decent Technics cartridge is only around £200. Fitting an even better cartridge, such as the Shure V15LT though others should soon appear on the market—will raise the musical potential of the deck. Then the technically demanding, as well as the operationally biased, members of the family will all be well satisfied: congratulations Technics.