Turntable Reviews

I won't debate here how to make a turntable's platter go around. Choose your favorite: belt vs direct drive, idler wheel vs belt, spring-windup vs wind power, whatever. As far as I'm concerned, there's nothing to debate. Each of these technologies has its pluses and minuses, but none can produce CD's accuracy of speed and inherent freedom from wow and flutter.

Despite that, you'll never convince me that CDs produce music that sounds better or more lifelike than LPs, or that CDs even come close to communicating music's ability to evoke emotions from listeners, or the sensation that you've been transported to the concert hall, or that the musicians are in your room performing for you. They just don't.

Play the best CDs for an hour and convince yourself that the technology has gotten really good—and it has—then play an LP on even a modestly priced turntable, and the sensations of quiet, relaxation, and relief are profound. As one friend who hadn't heard vinyl in years said when he heard The Clash on my turntable, "That's the sound I've been missing!" His decision was made in an instant: He got rid of most of his CDs and replaced them with the LPs he'd ditched when he went digital.

The Bardo
Brinkmann Audio built its reputation for turntables on belt drive. Then, wanting to produce a less expensive model, they devised an elegant direct-drive system for the Oasis, their first turntable to incorporate a plinth. More recently, founder Helmut Brinkmann has designed the Bardo, essentially a plinthless Oasis that more closely resembles the company's sleek, plinthless, belt-driven La Grange but costs less than either.

The basic Bardo costs $7990 and shares the superbly designed and machined spindle and bearing used in the Oasis, the La Grange, and Brinkmann's top turntable model, the Balance. For another $1500, Brinkmann will substitute for the standard acrylic platter mat an integral one made of precision-ground crystal glass, and add a screw-on record clamp. The glass mat includes for the record label a recessed area of stainless steel around the spindle to accept a raised washer insert. Screwing down the clamp produces a force around the record's perimeter that flattens it against the platter. A second option ($1490) adds a heftier outboard power supply for the motor, with a larger transformer that's said to increase the bass response. A slab of polished granite measuring 18" W by 1.25" thick by 12" D for the turntable to sit on is standard in the US. An isolation base, made by Harmonic Resolution Systems, which has had a long relationship with Brinkmann, is available.

The Bardo supplied for review included the glass platter and clamp but not the power-supply upgrade, in a complete plug'n'play package that included Brinkmann's 9.6 tonearm ($3990) and Pi moving-coil cartridge ($2700). Brinkmann will supply custom-drilled armboards for your choice of tonearms; Helmut Brinkmann was kind enough to include boards for my Graham Phantom II and Kuzma 4Point arms.

What any mass-loaded turntable sits on will have a great effect on its sound. The Bardo sat on my HRS rack atop an HRS isolation base tuned for the 'table's weight. In my opinion, the HRS rack is one of the greatest audio products ever manufactured.

A Non–Disco-Friendly Direct Drive
The Bardo and Oasis share the same neat, efficient direct-drive motor, designed and manufactured by Brinkmann. It consists of a large, eight-pole ring magnet mounted in the subplatter bearing housing, and a series of coils arrayed on a circuit board mounted below the magnet. An aluminum subplatter holds the steel bearing shaft, the ring magnet, and the tachometer. A circular fixture of machined aluminum, bolted to the plinth, contains the electronic drive circuit and the four field coils, which, interestingly, are not symmetrically arrayed at 90° angles to one another. Instead, in order to allow space for the control circuitry on the printed circuit board that supports the coils, they're arrayed at 22.5° angles, which puts the first at about 8:45 o'clock and the fourth at about 3:45. Why the space between the coils doesn't cause asymmetrical rotational performance, I don't know. Maybe it does. The bearing shaft, which rides on a Teflon thrust pad that sits in a machined aluminum carrier at the bottom of a circular opening in the center of the coil array completes the compact design.

Two Hall-effect sensors—ie, transducers whose electrical output varies in response to variations in a magnetic field—track the ring magnet's North and South pole positions, and direct an amplification system that precisely times the sequential increases and decreases of current flowing to the coils, as needed, to ensure smooth rotational performance. The concept is not new—see my review of the Grand Prix Audio Monaco direct-drive turntable in the November 2007 Stereophile, Vol.30 No.11—but the execution appears to be.

Though Thorens is credited with developing the earliest direct-drive turntables decades ago, modern direct-drive technology took into account the quick-start, quick-stop needs of radio stations and DJs. Thus, motors were high-torque, platters light.

Virtually all electric motors "cog," ie, their rotational speed regularly fluctuates above and below the average speed as each magnet pole goes past each coil. A high-torque motor needs a greater number of poles—in some designs, dozens—and the more poles, the more cogging. With nothing to counteract the motor cogging that inevitably occurs directly within the platter of a high-torque, low-mass, direct-drive turntable, large amounts of wow and flutter are also inevitable.

Regulating a direct-drive motor's speed with a phase-locked loop produces tight speed control and measurably low levels of wow and flutter, but the motor's constant, ultra-high-speed hunting and pecking as it over- and undercompensates in the attempt to produce a consistent speed can create a jitter effect in the mid-treble to which the human ear is particularly sensitive, adding a hard, brittle texture to music. That describes the sound of Technics' now-discontinued SL1200 series of direct-drive turntables, and explains why, despite their high build quality and relatively low price, few are used in serious audio systems, though some listeners claim that these 'tables can be modified to improve their sonic performance.