How much does rock-solid speed stability cost?

interesting thread. there is a review by Peter Moncrieff that will tell you (in his opinion) way more than you might want to know about speed issues with turntables.

turntable speed

the review is about the Rockport Sirius III. after owning a few very good turntables, including the VPI TNT and the Basis 2500, i can say that when the speed is perfect IT does make an astonishing difference in the basic reality of the music. if you read the review it will give you a deeper understanding of some of the issues involved.....even if you don't completely agree with some of what he writes.

whichever turntable you choose, consider a product such as the VPI SDS, which will allow you to correct the speed on A/C syncronous motors.

to answer your question......it costs alot to truely achieve rock-solid speed stability. i would add that there are many very good turntables that do a very good job in this area.....but any/every belt driven tt has it's limitations.

I always tought that a brush attached to any cartridge had to have some deleterious effects...

I knew the 1200 couldn't be at fault unless it was defective. The issue of speed/rotational stability to me is sooo important--you guys see me posting it over and over and over.

Yesterday I oiled my 1200 and the audible improvement was nothing short of stunning! The manual states every 2000 hrs, and I've had the TT working for 1-1/2 years (put away for the last six months). There's no way I could have played 3,000 records on both sides, but I saw a post in the Asylum stating that oiling should be done every year, so I went ahead and used 3 in 1 (with Kevin's approval). WOW! I was playing a salsa record which I know very well and the before and after was stunning!!! The bass was fuller and tighter, the percussion was snappy and with a very fast attack (especially the timbales!), the voices were sharp and well defined; sibilinace was softer. The soundstage became bigger and overall, the music was more penetrating and intense. Member Jahaira had told me a few weeks ago that he oiled his platter and the servo arm in his JVC TT and had a similar experience.

The way I look at it is that there was still oil in the bottom of the spindle, but that oiling the bronze bushing damped the rotation, providing a smoother operation, less noise and less speed correction from the Quartz lock drive. I also noticed that female voices were getting raspier towards the end of records and Kevin had suggested me I coud have damaged my modded Groovemaster by using it the first week @ 2g tracking weight. Not so. Now the voices and the overall presentation are smoother and extended.

Nighthawk, my suggestion is to get rid of the Type V damper and get yourself the KAB tonearm fluid damper. Zaikesman wrote a review and he's using a Benz Glider MC with his 1200:

http://forum.audiogon.com/cgi-bin/frr.pl?raccs&1033259530&read&3&4&

This issue of the platter providing the time domain is really important. The belt drive crowd doesn't seem to get it. I've gone through all these efforts of modding the 1200 because there is simply no TT around it that can deliver the needed speed/rotational stability. After this experience with oiling the bearing I truly believe the 1200's outboard power supply is going to be a very welcome addition to my system.

Just wondering, is there anything out (current production model) in between the Rockport and the Technics 1200?

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".