Is Direct Drive Really Better?

Zaikesman, I have to admit that the direct drive choice was based almost entirely on theoretical reasoning. The initial quest was to produce a better quality motor using some new techniques that I had been musing about for some time. When examining drive methods it looked like DD had the most potential (ie lack of compromises). But at the same time it also looked like the most difficult and risky approach. A little isolation can cover a lot of motor sins and with DD you get none. I also looked closely at idler drive. From a theoretical perspective it seems that idler drive is somewhere between BD and DD. Some isolation but less than with BD. I happen to think that idler drive has a lot of potential and suspect that at some point I will experiment with it.

In the end I settled on DD because I believed that this new motor would have low enough torque ripple that DD could be used without compromising the smoothness that is characteristic of a good BD table. Our first DD incarnation confirmed my theories. It had great pitch stability, drive and rhythm but sadly lacked smoothness and refinement. But with some considerable effort the smoothness and refinement has now surpassed our best BD motor. So is the success due to the motor or the drive method? The answer must simply be yes.

Fortunately, or unfortunately, marketing had little to do with the decision. It's going to be difficult to recoup the development costs for the DD motor. Sadly the motor is expensive to produce so I doubt it will ever be sold in volume. But I can say that it has been one of the most personally rewarding ventures I have embarked on.

Perhaps the original question should have been: Why do belt drive turntables have a reputation for better sound quality than direct drive turnatables? (This ignores the rim drive fans who are definitely a niche market group). With the question phrased like that the answer becomes much clearer. It is in two parts:
1 The Linn/Naim axis in the 70s did a superb job of marketing the Linn LP12 to such an extent that the audio press started to doubt their own ears. The result, only belt drives were worthy of audiophile ears.
2 The japenese giants saw DD as a way of producing TTs cheaply and sacrificed sound quality in name of the God profit.

As a result the point marked 1 became a self fulfilling prophecy in the domestic market. It was only in professional markets (broadcast studios etc) that the true benefits of DD were realised.

Which is better? Neither, each has its own pluses and minuses. Execution is all in the quality stakes. It is a fact that the domestic turntable development suffered irreputable harm at the hands of the Linn/Naim hysteria of the 70s. (That and the arrival of CD) stiffled the development of the TT.

One last thought: I would never buy a turntable without specifications, not because the specs dictate the neutrality of the sound but because if I am to lay out hard cash I want to make sure the manufacturer is not ripping me off and I have something to bash them with if my purchase does not measure as it should

Specs...It is obvious that the sonic character of a loudspeaker cannot be defined by specs, although some things like frequency response can be usefully measured. However performance requirements of a TT (not the arm/cartridge) are so simple that I think that specs can tell the whole story.

1..A TT must rotate the LP at exactly correct speed, and without speed variation for reasonable stylus drag force variation.
2..A TT must not generate a magnetic field at the cartridge.
3..A TT must not generate vibration, for example rumble.
4..A TT must attenuate vibration of the base it is mounted on.

All these can be accurately measured. The only issue is to determine what acceptable values might be.

And remember that the real reason for specs is for the manufacturer to verify that each unit he builds has been properly manufactured and assembled so that it performs as well as the design permits. Use of specs to assess the quality of the design is something extra that people do with specs. It is more valid for TT than for most other audio equipment.

As a proponent of the "niche market" rim drive group, I would suggest that Eldartford omits probably the most important character of the TT-resonance frequencies. I grant that he does mention vibrations. My real question, as always, is how do specs. capture this. Again as always, all I want is to hear the TT. I did hear the Shindo/Garrard 301, and I bought it.

I should say that regardless of how good it sounded, putting it on the Halcyonic base greatly improved it. Again resonances. Would it not be great to have freedom from resonances.

Dear friends: There is other point that " speaks " in favor of the DD system:

from what I know the cutting lathe machines ( that " make " the LP ), like Neumann, Fairchild, Scully, etc, etc, has DD design not BD/IW. Wonder why?, yes you have the answer.

Regards and enjoy the music.
Raul.