How much does rock-solid speed stability cost?

Now, before this direct-drive love-fest gets too out of control, let's talk about some other issues.

First, the "belt-drive crowd" does get it, and there are turntables out there that do not succumb to any of the things that Moncrieff points out in his turntable article.

For example, a quality ironless-core, non-cogging DC motor provides a perfectly smooth output. So using a motor of that type takes you a good part of the way there. Next, using a non-suspended turntable takes the subchassis interaction out of the equation. Third, having a non-stretch belt, combined with the above 2 things, eliminates the "stretch-release-stretch-release" syndrome that Moncrieff talks about. So no cog, no platter/belt interaction, no RC-tank effect interaction with belt and subchassis. What's left? Motor speed control. And heavy platters provide the momentum needed to reduce/eliminate the effects of stylus drag, making speed adjustment very infrequent, and maybe not even needed during the play of the LP. If speed adjustment is required, slow application of this adjustment will make it nearly or totally unnoticeable. A quartz-lock mechanism will not allow slow applications of change, and make immediate changes in a very small variation tolerance, so speed does not vary alot in amplitude, but it does vary alot in frequency. It "hunts" for speed. Up and down and up and down. This is true in either belt-drive or direct drive. Some may say it is perfect because of tight specs, some may disagree. So, as you can see, there are belt systems which do not suffer from these "demons" that Moncrieff waxes so epically about.

Now, direct-drive motors are inherently directly connected to the platter by their shafts, and all motors vibrate. ALL. When the motor vibrates, this vibration is directly coupled to the platter, and the platter vibrates. The vibration of the platter during play can and will cause information loss or distortion, since the record is moving microscopically under the stylus in directions other than the time axis. Better main bearings can minimize this effect. So can heavy, well damped platters.

Belt-drives on the other hand, have the motor somewhat isolated from the platter by the belt, and much of the motor vibrations are damped by the belt, and gone by the time they reach the platter. Since they invariably have some reasonably heavy platter weight, any vibrations coming into the platter will be of low magnitude, and easy for the platter to damp.

As I tried to show here, a well thought out belt drive table has much to recommend it, including good speed control and high vibration isolation, and there are a number of belt drive turntables that perform at extremely high levels. Poor belt drive tables are not an accurate representation of what belt-drive can do, just as poor direct drive tables aren't a good representation of what direct drive can do.

The absolute worst combination possible, is a cheap direct drive, cogging motor, quartz-locked, light platter turntable. These were typical in the late 70s mass-market units. They vibrate, cog, and hunt, with very little compensation from platter weight. Next up is a a cheap belt drive with a poorly designed subchassis, rubber belt, AC cogging motor, and cheap light platter. Neither of these is a very good choice. These are primarily what Moncrieff was talking about. IMO.

At the highest levels, both technologies may be good, but the execution of each design will determine how great it is.

Speed control is very important, but it does not exist in a vacuum. Vibration induced into the platter is also an important aspect of the design. They should not be considered as separate from each other, since the overall performance of the turntable is dependent upon BOTH of these parameters, and not just one or the other. This is why bearing design, platter design, motor and speed control, and vibration control and damping, are included in turntable design. Failure at any one of these criteria will result in a poor sounding turntable. The steps up the scale of performance reflect the proper addressing of all these points together.

Tom, there is no physical contact in the 1200's platter, except for the spindle. The magnet is part of the underside of the plater. The chassis is non resonant and made up of three components: molded rubber base, a composite midsection and an aluminum top. You can see the diagram in http://www.kabusa.com. The creature is pretty well designed and borrows technology developed for the SP-10 series. It would take a high end company millions to develop such technology from the ground up. The mods take it into full high end operating mode.

The other day I was at Lak's and we were talking about TTs (you know he wants to get one). He said he heard the Teres at the Midwest Audio Fest and that it sounded good to his ears. That he's also heard mine with an entirely different system and acoustic scenarios but that it also sounded good to his ears. Lak would love to hear a fully modded 1200 next to a Teres to really find out how they sound--even if that means a trip to Appalachia.

If belt drives are so fantastic, I wonder why record cutting lathes were either DD or rim drive--even for the Audiophile labels...

Yes, Francisco, I realize the magnets are built-in to the platter. That makes the platter part of the motor, and the spindle is the motor shaft, and the main bearing is the motor bearing. That is the point that I was making.

I'm simply pointing out design methodology. Certainly you agree that nothing is perfect.

I know Lak is interested in a turntable. He's emailed me several times. I don't know what he will end up buying. His price range favors the 1200. You don't really have to A/B against a Teres, just against any sub-$3k tables like a Basis or VPI or something like that. If it can beat any of those, then it is well worth the savings to get the 1200. If it can't beat those, there's no sense in even comparing to the Teres.

The answer to your last question is, "torque".

in the 'real world', a high-quality belt-driven tt is the way to go. i agree with Twl that it is possible to minimize (not eliminate) the design limitations of belt-drive to a degree that makes them non-issues unless compared directly with the Rockport.

when Twl mentions 'torque' as far as cutting lathe's; that brings to mind the servo-mechanisim of the Rockport. the servo on the Rockport keeps the speed with-in 10 parts per billion dead on regardless of groove modulations......the 55 pound platter comes to full speed in 3 revolutions and stops with-in 3 revolutions. it takes 'torque' for this to be possible.....both on cutting big groove modulations and playing big groove modulations with no speed instabilities.

In the 'real world', the 1200 is the world's best selling TT. Why? because it can be used for DJ'ing, broadcasting, record libraries, archivists, audiophiles, etc. It is easy to set up, low maintenance, built like a small tank yet very precise, has high torque (1/3 rev start) and an electric brake. Truth is it takes a lot of money to make a belt drive work right, with all its inherent limitations. Most people are not chronic audiophiles and in reality, how many people can afford such things? I have a group of friends who, like me, have worked in A/V stores, record stores, are musicians, started playing with stereos in high school, etc. Of all of them I am the one who is really into audio and the one with the most sophisticated system (wish I could say that of my record collection). Even though I'm buying used, demo and price point gear, my system is approaching $7-8K. This has to end--soon. I need to move on.

Because of its inherent strengths, Kevin has gone through the trouble of developing the 1200 mods. He wants as many people to have high end performance on a budget. I still don't know how far the full mods will take it, but I'm willing to drive 3 1/2 hours each way to take my 1200 to be rewired by Ridge Street Audio. Next will be the outboard power supply.

Tom, there is one of the facilitators in Audiocircle with a Teres. He lives a couple hours from me. It's sad you don't want to meet us. Lak has three dogs and they all like me...