VPI Classic Direct Drive Signature turntable The Attraction of Direct Drive
Drive the platter directly at the correct speed and you're done. So simplewhy didn't Technics think of it? They did, in 1969, with the SP-10, still considered one of the finest of the genre. Throughout the 1970s, the "golden era" of super-turntable designs, many Japanese manufacturers followed suit. Platters became coil holders (rotors), and so an actual part of the motor. Add servo circuitry that constantly fed back speed information to an "electronic brain," and you theoretically had a high-torque turntable that always ran at the perfect speed.
The problem was that many direct-drive turntables didn't sound very good. Motors cogged (ie, didn't rotate smoothly) and were noisy. In addition, servo systems overshot their marks as they constantly sought the correct speed. While the average speed looked perfectly stable at 331?3 or 45rpm, the servo's hunting and pecking produced a form of jitter that created what many heard as hard, bright sound. The more you understand and consider the opening section of this column, the more easily you can appreciate the potential sonic damage done by these microvariations in speed. Add poor shielding from motor-induced RFI/EMI, lightweight plinths and/or platters, and it's understandable why belt drive, which has its own problems, has long been the industry standard (though rim drive, too, has its adherents).
In the past few years, direct-drive turntables have appeared from Brinkmann Audio, Grand Prix Audio, Rockport Technologies, and Wave Kinetics, some better than others. As with anything else, the implementation of a technology is more important than the choice of technology itself. Listening is more important than, or as important as, measuring.Michael Fremer