All hands on Dec

By Andrew Harrison, Hi-Fi News & Record Review, May 1999 (reproduced with permission of the editor)

Michell Engineering has gently revised the venerable GyroDec to create a most worthy Spider Edition

Usually, adding SE after a name is a good excuse in upward price revisionism, then followed with self-lauded claims for superiority over the standard version. The Gyro SE is different. For one thing, the manufacturer makes no particular claims for improvement over the previous model (despite there being… well, read on), and more shockingly, the SE is cheaper.

The differences between the standard and the SE are as follows: where the standard has a full-width acrylic plinth, to support the motor and form a clam with the matching lid, the SE has no lid and very little base plinth to speak off. The base has been pared right down to form a web that just support the three-point suspension turrets and associate feet. Whereas the motor was formerly attached to the turntable's base, it is now free-standing, in a similar fashion to the top-notch Orbe, while still residing in the same relative position. What this all gives is an even more modern looking apparatus, not so very distant in outlook from recent record players from Pink Triangle and Wilson-Benesch. With a price saving of £***, from £*** to £***, plus the ability to build back up to standard spec at any time, the new SE is creating a stir in vinyl circles.

The beauty (in engineering terms) of the original GyroDec design is the cast aluminium subchassis, designed to keep the centre of gravity through the platter spindle by matching an arm to a balanced platform. The mass at the rear right corner remains a constant 1kg, regardless of arm, because the platforms are tailored to suit any named arm. An RB-300 takes a heavier platform than an SME V, for example, and the necessary base can be specified at time of purchase. Getting the mechanics balanced ensures that the platter's centre of rotation and centre of gravity coincide, avoiding any asymmetric turning moment to upset equilibrium, and making arm lead dressing less crucial to subchassis stability and, ultimately, sound quality. Tonearm leadout cable still needs respecting, as there is now no point to anchor it to on the turntable. Providing it is not under tension en-route to an amplifier it shouldn't affect the dynamics.

The platter, the most visually arresting feature on the GyroDec, is not all executive toy, either. Michell was intend on keeping mass around the circumference of the platter, but without the ringing resonance that is typical of metallic types, where the mass runs continuously around the outer edge. Instead we have the GyroDec trademark, six solid brass cylinders, heavily gold-plated, suspended below the composite platter. This platter is composed predominantly of acrylic again, this time alloyed with carbon and vinyl, its composition ultimately providing a very close match to that of the vinyl record itself.

Drive of the platter comes from a Papst AC synchronous motor, securely mounted inside a cylindrical tower block. The Papst is a German-made unit, characterised by its external rotor. Unlike the ubiquitous Airpax type seen on Linns and Regas, the Papst has no discernible 'cogging' - that is, no cyclic resistance to rotation that can easily be felt on most synchronous motors. End result: little cogging vibration passed through the motor to the record/stylus interface, giving a much cleaner sound even with an elementary power supply. This motor's two-step pulley feeds a round section belt around the outside of the platter. Speed change to 45rpm is achieved ordinarily by pulling the belt down to a larger diameter section, and the turntable is started and stopped with a little green press switch on the motor unit.

Quality, Controlled

The motor takes 19V split phase power from a basic supply unit, rated at 40VA, and this serves well in making the SE package a literally 'going concern'. But best performance will not be realised until it meets with Michell's QC power supply. Using a pair of quartz crystals to fix 33.3 and 45 rpm speeds, the QC delivers a regenerated 50Hz or 67.5Hz sinusoidal waveform, with precise 90° phase shifting for each speed. This QC is built into a distinctive case composed of a flat cylindrical toroid on one side and upright PCB encased in translucent black acrylic on the other, separated by a finned heatsink to keep the driving transistors this side of meltdown. Or, pictured another way, think Alecto poweramp, downsized. To flip between speeds, a small button on top is pushed, and selected speed is flagged by a two-colour LED inside the case, green for 33.3rpm, red for 45rpm. The QC power supply, which also powers the Orbe as standard, costs £***.

Assembling and setting up the Gyro SE is straightforward, the turntable coming well packed with all mechanical components individually wrapped. Except for the mechanically minded, this task will best be left to a dealer, at least until such time as an exploded diagram is enclosed. This review was done with a Michell-badged RB-300 arm, available for £***, even though the SE is a versatile platform capable of supporting much more sophisticated designs. The (one of the) problems of the Rega arm is the absence of arm height adjustment. This became a problem with the deeper-bodied Ortofons, offset by the promise of a forthcoming sleeve kit from Michell Engineering that will make VTA adjustment easy. In the meantime, one has to fiddle with spacers.

Suspension is another area that has been revised, the main springs in tension now needing less manual manipulation to centre within the suspension turrets. But arguably the biggest lift to performance can come from the new external siting of the motor unit, taking residual motor frame vibration away from the platter. When setting suspension bounce this will need to be shuffled inside the sub-chassis cut-out to give best clearance all around its diameter. Once in place the ensemble works exactly as the standard GyroDec.

Sound and Around

The first disc on the platter showed some of the secrets this skeletal piece of engineering held. Sited on nothing more than a piece of MDF, with Rega arm supporting an Ortofon MC-25FL cartridge, the SE had the understated flow of a consummate pro. From front to back the sound field opened into believable space; tonal balance showed the characteristic of the cartridge (in this case extended and clear both ways with little artifice). And this was with the standard power supply.

Impatience getting the better of me, I connected a QC power supply by the little 3-pin Bulgin plug that dangles from the motor unit. The differences the better motor supply showed were three-fold. First, and noticeable even before the tunes started, was a drop in surface noise. Not a total removal of, but a perceptual reduction in, which was more apparent when the music actually started. This, I felt, was alongside a refinement in pitch definition so that attention was held by music to the exclusion of background noise. The piano in Mozart's Quintet in E-flat, K452 [Decca SXL 6252] held a natural size with impeccable pitch. 'Nil sen la' from Clannad in Concert [Shanachie 79030] showed the clean and tuneful double-bass, without smear or bloom, as acoustic percussion traced around instrumental breaks.

Surface noise generally was fractionally higher when comparing the same discs with LP12 playback; so the Ortofon Rohmann usually resident on the latter was moved across to the Gyro to make comparison easier.

Generally, the gains in detail, space and neutrality over the generic LP12 sound made the extra insight available with the Gyro SE a worthwhile trade.

It did however become obvious that the RB-300/Rohmann pairing was not ideal, the Rohmann deserving an arm with more control than an off-the-shelf RB-300. So the next offering was a moving-magnet cartridge, in the shape of a Reson Reca.

This certainly proved the better combination, the total sounding even better than the sum of its parts. Clannad in Concert now held more of the atmosphere of a live event, with better feeling for the interplay of acoustic bass, percussion, and voice. The Mozart Quintet captured the ebb and flow of the passages better, despite some thickening of piano timbre.

Compared to most time-honoured suspended sub-chassis designs, the various ARs, Aristons, Thorens and of course the Linn Sondek, the Michell GyroDec has a sound quite removed - clean, taut and highly transparent, without losing the pulse of music stirred by its respected peers. It has unmistakable naturalness and 'ease', allowing the music the flow unencumbered, as it hypnotises you with its ever-spinning carousel.

The traditional sprung decks (invariably powered by the 250rpm Airpax/Philips motor) can have an irrestible warmth, a euphonic seduction caused in part by motor cogging resonances around 100Hz, and this has become ingrained for many people as part of the analogue allure. Recent times have seen improved power supplies which reduce motor frame noise to vanishingly low levels - leasing new life to the credo and allowing the decks to compete with digital in accuracy terms. And the Gyro SE overcomes most of the remainder of the subtle colorations, to produce a highly informative and musical turntable. Another classic reference, especially at the price.