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

While it has been several years I do remember hearing a demo of the prototype Teres Certus. I recall that there was/is a difference between the Certus platter and that used on the non-DD Teres tables. One of the differences was the use of a significant amount of brass. This was on my mind during that demo. How much of the presentation was due to the drive and how much was due to the difference in platter material? I suspect a bit of both, and I do believe that there were differences in arm/carts. To Ralph's point, the surfaces were the same as far as I know.

I don't know if the present Certus controller offers the torque adjust feature that was on the proto. That adjustment did make for an effective demonstration of the effect of torque on the sound. At one point the torque was turned up such that the sound changed immediately from analog to digital.

Since that time I've never stopped wondering if the transient sounds I'm hearing are real or not when I am experimenting with speed. I posted earlier about my experiments with really taught mylar and a more robust controller. At present I am drawn to the sound, but my mind still asks if it sounds real.

As interesting as this all is, I feel the need to remind myself that not everyone agrees with what I think LP playback should sound like. There are many people in this hobby that prefer what I would call sluggish and syrupy presentation.

One other thing I wanted to add was with respect to what can perceived as a cartridge alignment issue, which in reality is actually a micro-dynamic speed issue. I don't know what other term to use to refer to this, hopefully you guys can get a hint of what I'm on about. I would guess this is probably more prevalent with belt drives.

Hiho,
you reflect my own listening experience and thank you for sharing your own findings on that.

Even with quite, or REALLY powerful motors like I've heard on an Transrotor Z3 or on a Thorens 2010 (motors where modified, with beefed-up controller power-supplies), due to the long thin belts they remained still more laid-back then e.g. my SME, even though one could notice some improvement in the dynamics department. Two motor yet did a little more but still just don't seem to get there.

Problem with a lot (more affordable?) DD's is the 'affordable' motor/controller as I understand it. It seems VERY difficult to get this completely right, because of the DD's 'unforgiving' 1:1 coupling.
Despite some of the ~ strange Linn 'behaviours' (some love it some don't), I think they got the motor to platter coupling just right I.E. sub-platter, short belt, powerful enough motor.
SME I think went a step further, smallish as the Papast-motor is, it pulls like a train, has a lot of torque --- BUT they had to spend some time and money on a very good motor-controller without it, it would NOT work.

The spec.: Reference oscillator is a 10Mhz quartz crystal, multiplied by 4 to obtain 40Mhz microprocessor clock speed. Driver stage has CMOS buffers/MosFet drivers with 1.2 Amp peak drive capability.
Power output stage is six high power complimentary MosFets in a 3 Phase Bridge Driver configuration.
Close loop speed control is implemented using pseudo sine wave commutation sequence and a proportional-plus-integral (PI) algorithm.

So, there you go. This is not some wall-wart using the power-line cycle for speed control. With a long 'forgiving' belt it will work fine, but the closer you get to 1:1 drive-line coupling the more need to have a close to cog-free drive with torque to boot.
Greetings,

If a turntable company has succeeded in making several versions of a turntable, essentially with different drives, while at the same time keeping the platter pad and platter signatures exactly the same, I would agree that the differences one heard in them could be ascribed to the drive.

However- the drives themselves require that the platter design be different! Thus I severely doubt that *any* company has demonstrated this successfully.

In working with the Empire into its evolution into our model 208, we found that the platter pad affected the sound, but if you did nothing to control the resonance of the platter itself, you were missing a bet. IOW, although the pad I've been working with is head and shoulders better than anything else I have seen, it still did not control the platter; damping the platter was still a major improvement.

BTW, the platter pad in question was designed and built by Warren Gehl (currently at ARC) about 20 years ago. It was used by SOTA on the first 50 to 75 Cosmos tables, at which time the formula got modified. So an early Cosmos would have some of the same advantages, if you could fix the drive. I use this pad on my personal table only.

I find it astonishing that platter pads have received little or no attention in the last 2 decades, despite the extreme importance they play in controlling vinyl resonance caused by the needle tracking the groove. Resonance control otherwise has been one of the biggest strides in turntable technology over the years- but almost no work on the place where it counts the most.

And for the record, if the mat is too soft, like a rubber mat, dynamics will be suppressed. The interface has to be exact- the pad has to be the same hardness as the vinyl, so that no energy is reflected back to the LP, yet the mat has to immediately absorb the energy. Acrylic mats are too hard, rubber and felt way too soft. Honestly if these things are not sorted out first its almost impossible to tell anything else about the table! My advice is to try it first before you knock it. The only problem is- where do you get a proper mat and for that I have no answer- there isn't one anymore as far as I can tell. That is how bad this situation is- the platter pad is one of the most audible artifacts of a turntable excluding the arm and cartridge, and there are no definitive pads even available.

Warren saw to it that a good number of serious audiophiles in the Twin Cities area had his pad (FWIW he spent about 5 years perfecting it- I personally had about 5 or 6 earlier versions before he got it right). So we have had ample opportunity to compare it on the SP-10, SL1100, Conneseur, Rekokut (idler drive), Empire, SOTA, and the like. FWIW, a salesman at one of the local shops figured out how to install the pad on a vacuum SOTA, which resulted in his getting a job with SOTA. That person was Allen Perkins, and is why the early Cosmos tables featured that pad.

Atmasphere,
hope I don't sound boring by now?
Ever bothered to look at that funny platter-pad material of the SMEs at all?
Re: >> I find it astonishing that platter pads have received little or no attention in the last 2 decades <<

Not so, I'd say.
Bonded copper-pad of TW, bonded vinyl-pad of TransRotor, bonded cork-pad by Acutus, bonded glass by Brinkmann, non-bonded felt by Linn :-), etc. those are all pads on the platter, even though they are bonded except Linn.
Does that make the difference with your definition?
Axel