02-24-09: Craig_c
Thanks for the input on the motor bearings. I had gotten the impression that direct drive is more accurate than belt drive, but recently I've been hearing that the DD can have motor rumble transmitted through the system.
That claim--that DD tables are inherently noisy because the platter is an extension of the motor spindle--has taken on the status of dogma among belt drive purists. I've seen it repeated in Stereophile and proffered by many audio sales people, but have never seen anything to substantiate the claim. In fact, the measurable signal-to-noise specs on the Technics and Denon direct drive turntables rival or exceed the noise specs on all but the most expensive (north of $20K) belt drive turntables.
Back in the '70s and early '80s there were probably some shoddy low cost DD tables that had compressed dynamics and a high noise floor, but even then I doubt that it was the motor. Most of the DD motors were made by the inventor, Matsushita, parent company of Panasonic and Technics, so their noise specs and precision would have been similar. In a cheaper implementation, however, that motor might have been mounted to an inferior plinth, accompanied by an inferior arm.
Probably what got this dogma rolling is that the Linn and AR turntables (and later, the better BDs that followed from SOTA, Michell, etc.) were suspended designs. Belt drive designs lend themselves to suspended designs easily; DDs do not. But it is easy to create your own vibration isolation platform for a DD that absorbs the turntable's extraneous vibrations and isolates the plinth from in-room noise and vibrations.
