Direct Drive turntables


I have been using belt drive tt's. I see some tt's around using direct drive and they are by far not as common as belt drive ones. Can someone enlighten me what are the pros and cons of direct drive vs belt drive on the sound? and why there are so few of direct drive tt's out there?
Thanks
128x128alectiong
And yes to Raul,
+++I repeat again again and again ( many times everywhere ) that the mat/platter build material where the record/LP seats directly is almost the more important subject/factor to achieve the highest quality performance+++

I have to fully agree to this basic tenant. As Yoda would say “most important is the platter to the record interface.”

I would be more on firm ground in this thread to think of the differences in terms of _difference of coloration_.

Pure lead or a high lead mix: sound has a dead "it-ends-here" coloration. very accurate reproduction of the space between the images and notes.

Hard rubber like formulas: detail and depth to the coloration, a color not unlike putty or clay, very nice space between the notes but flavored with something extra.

Clear Acrylic: more of an endless feeling to the coloration, almost a reverb of select frequencies are accentuated. Have to get used to.

Special formulas (Goldmund, Lurne' and other Alchemist designers): a small shadow coloration that follows the music, like SETs somewhat. Very addictive to my ears at this time in my career. Huge space and you can minimize a touch of gold glow if you roll up your sleeves and try creative belts, AC/DC drives, and outboard motors.

Peter
This is a most interesting post and I thank all the knowledgeable Goners for their contributions. As Raul stated, sharing knowledge is important. And 75 comments in just one week clearly shows the level of interest in this topic.

BUT, if I understand this point correctly, I have an issue with one suggestion made a few times here. That is the idea that it is necessary to test different drive systems with "all else being equal". Really? Since I believe many contributors here are in fact knowledgeable audio folks, you may agree that component compatibility is very important in this hobby. If so, why would we assume that the same cartridge, arm, plinth, suspension, support, etc. systems would be "ideal" with different drive systems?

My contention is that the only way to compare different drive systems would be to do so with each one "optimized" for best performance and therefore not compromised. Of course then we have the problem of optimized by whose standard or taste?

So just like there being no one speaker that works best in every room, or with every amp, I guess it is up to each of us to find which drive system, in combination with our other vinyl playback components, brings us the most satisfaction. Pax.
Pryso, It depends on what you are trying to accomplish. If you want to get an accurate understanding of the sonic affect of a particular component then you want everything else to remain constant. In this case it's about gaining understanding and not necessarily optimizing for the best sound. With understanding of the contribution of various components in isolation then you are in a much better position to then optimize.

It is certainly possible to make meaningful judgments without everything else being equal but it is much more difficult and more error prone.

There is usually some synergy between components, but I believe that as the level of quality goes up this becomes less important. I think that a motor implementation that requires a particular tonearm or cartridge to sound optimal should be considered to be flawed. A quality, neutral implementation of any component should work very well with any other quality component. Of course in the real world this all too often is not the case. But it should be a goal of good design.
Changing drive alone would be a purely academic exercise, except for perhaps for those that might be willing to custom build their own table.

Practically, it is the overall design and integration (table, arm, cart, phono pre-amp) that matters for most. Any type of drive mechanism, if done well, will work just fine.
The experiment has been done by anyone who converted his Teres or VPI turntable from belt- to rim-drive using the motors now available from the respective manufacturers. In these instances, all other factors are held constant; only the drive system is changed. As far as I know, almost all end-users have preferred rim drive vs belt drive. One could be skeptical of those claims, because there is a lot of subconscious bias in favor of hearing an improvement, in my opinion, when one spends money for such "upgrades". (The very use of that term suggests a bias.) But I am inclined to believe that the benefits are real, based on my own completely uncontrolled experiments comparing a "good" belt drive table to various idler-and direct-drive ones. (I am a scientist by profession, so this stuff bothers me.)