Direct drive/rim drive/idler drive vs. belt drive?

Wow, what a great discussion. As a Galibier owner, I can't wait for RMAF to audition the new motor/controller.

I tend to agree with the opinion that while each design has its particular set of strengths and weakness (resulting in a signature sound), excellence in implementation is critical. The Saskia is a very different from my Galibier and each have their own sonic signature, however, I would be happy with either. With a well-designed system, it's not 'better or worse', it's a matter of taste.

One additional variable that hasn't been addressed is production variability. Since many of the high end tables have limited production runs, I would guess that there is variability between each table produced by a given manufacturer.

My wife and I experienced a similar phenomenon when we purchased our piano. After months of auditioning, we decided we perferred the Steinway sound. We spent many hours over two counsecutive days, auditioning 18 Steinway L models. Each piano had the Steinway sound, but every one sounded and played a little differently. On the 2nd day of our auditions, Van Cliburn was visiting the dealer's showroom and he played each of our finalists. That really brought out the individual personality of each piano. (Analogous to the difference between having your analog system set up well versus set up perfectly).

Can we get back on track talking about the genres of turntable drive system?

It's not that I don't believe the improvement of a turntable mat - of course they do - but we were talking about the TYPE of improvement, in what area the mat will improve the most and some of us simply question it will improve the "slam", "drive", or rhythmic quality, not tonal quality, that, we believe, has more to do with the drive system and, in my experience, particularly, the motor. I will be happy to be proven wrong that a turntable mat will improve across the board in every sonic area to the point where it even matches or surfaces replacing a mediocre motor with a better one. If there's cogging or speed irregularities or speed drift, wouldn't it make sense to address the motor, which is the singular active component in the entire system? For some reason, the thread ended up talking about turntable mats. Many stock Empire 208 turntables are a little fast, please illuminate me on how a turntable mat can make the speed spot on.

Back to motors or drive systems, shall we?

Question for Mr. Kelly. Is there a technical explanation on why, at least to me, most coreless motors in a direct-drive system sounds smoother to my ears? I know they've been advertised as having less cogging or coggin free and I have to admit they do sound silky smooth. They tend to have less torque and, again to my ears, less dynamic but I am willing to trade for smoother sound than just dynamics. Even on a cheap Pioneer DD table with coreless motor that I acquired recently I heard the purest smoothest violin sound from a turntable. Sonically, I am sold on this type of motor. Typically I choose a high torque core motor DD table to tape-drive my passive platter to equal the smooth sound of a DD table with coreless motore.

HiHo

Here are a few things which I can prove to be true:

1. Newton's Third Law of motion holds for turntable motors so the reaction torque reflected into the chassis will be the mirror of the forward torque applied to the platter.

2. The variation in reluctance of a "coreless" motor is much smaller than that in a motor using an iron cored stator.

3. As an iron cored DD motor rotates, the servo loop compensates for the variation in reluctance by decreasing torque as the rotor pulls towards the lowest reluctance position and increaes torque as the rotor pulls away from that position. This happens many times per revolution, depending on the slot and pole numbers of the stator and rotor respectively. The exact quantum is the least common multiple of the slot and pole numbers.

4. It follows from 1 that the torque variation reflected into and propagated through the chassis is much smaller with an ironless stator than with an iron cored.

It is my conjecture that this phenomenon explains what you are hearing. Naturally I cannot prove this so I won't say that it is *definitely* the case.

Some support for this idea comes from some engineering work done at Sansui towards the end of the analogue era where they designed a DD with two counter-rotating platters to obviate the problem (called X-99 I believe).

Mark Kelly

Dear Hiho: It is obvious that a TT build material ( any ) can't fix a mediocre motor that ca run on " speed ", but I think that is not the subject on what Ralph want to share with all of you.

I can tell you that through my TT experiences through the years ( dozens of TTs ) almost all main factors on TT performance are already addresses but the TT right build materials.

You can find several threads like this one speaking one and again the same TT topics with no single real advance out there.
I know that everyone has a lot of fun reading and making some TT changes on its systems but that main factor ( TT build material ) remain almost untouchable: I wonder why?. The " sad " issue is that almost all analog people does not care about just like you.
It is obvious that maybe does not care about because don't understand the critical importance on the TT build materials that like I posted the differences in quality performance is: night and day !!

I understand too that because almost no one already experienced what Ralph and I " live " there is not to much of what to talk/share from almost all of you.

IMHO and like Fm_loging posted: we have to evolution if we want to grow up and if we want to improve what we have.

I'm on evolution and that's why I share with all of you my findings. Stay steady where you are is up to you and fine with me.

Regards and enjoy the music,
Raul.

Mark, Just out of curiosity, do you know anything about the build of the motor in a Denon DP80, iron core or coreless? I do know that it is a 3-phase synchronous AC motor the speed of which is controlled via the servo by varying the frequency of the AC. This is different from the SP10, but I had not thought about whether the DP80 motor had an iron core or not. Indeed, I did not appreciate the significance of that fact until Hiho and you had the exchange above. I ask because the DP80 gives me the very same "smooth" feeling that Hiho experiences with his Pioneer. In a heavy slate plinth, the Denon is rather addictive.

Raul and Ralph, I hope some time it will be possible for you to reveal the nature of these especially good tt mats. It would be fascinating to find out whether both mats were made of similar materials.