Along with about a half dozen other projects i have going right now, i'm in the process of slowly setting up two different tables. While they don't mention the suitability of this product for use in turntable's, i'm probably going to try using TufOil in one of them. Since it is the most slippery substance known to man, i can't see anything doing a better job of lubricating the bearing / reducing drag on the motor. Sean > |
If it is simply a matter of lubrication, there's no contest. I've already posted a link to what is the most slippery substance known to man. Since the whole idea of lubricating a bearing is to reduce drag on the motor and increase the longevity of the bearing itself, using the product that reduces friction to the lowest possible levels and has the highest lubrication factor should obviously work best. The fact that this is a thicker substance would also allow it to cling to the bearing rather than just run off of it. If you want to see what i'm talking about, take a look at this comparison of various lubricants and oil additives. Look at how long Tufoil lasted compared to the 22 other lubricants. While the average failure time for these 22 other formulas was appr 7 minutes, Tufoil lasted 16 DAYS under the same test conditions !!! While the average failure temperature for these 22 other formulas was appr 79 degrees, Tufoil failed at 60 degrees. That is an appr reduction in operating temperature of 25%. Since friction and heat are what cause bearing failure and metal fatigue, it should be common sense that reducing the friction and lowering the operating temperature would produce the longest lifespan for all the materials involved. Sean > |
Herman: Those are all good points but you're making it far more complex than it really is. The reason that we have different fluids in a car has to do with the materials and applications being used. ATF is different from motor oil because ATF is used as a hydraulic fluid with detergents and lubricants added. It is not exposed to gasoline, anti-freeze, carbon, etc... and the clutch materials inside the transmission are of a different compound than any of the materials used inside of a motor. The fact of the matter is that it would be hard to improve upon a situation requiring lubrication when you're already using the slipperiest substance known to man. So long as one did not exceed its' thermal limitations, which would be hard to do because of the reduction of heat involved, how could you reduce drag & friction any lower? If this lubricant won't work here, what is it that would allow other lubricants to work better? Neither would be under any pressure other than the weight of the platter on the bearing. On top of that, there's no circulation system involved, so flow time isn't a concern. You basically have a bearing sitting captively in a machined area that needs lubrication. There's nothing high tech or diverse about this application what so ever. Sean > |
Herman: Tufoil is basically a combo of specially formulated thicker oil mixed with moly grease that has microscopic particles of PTFE imbedded in it. It is neither as thin as oil nor as thick as grease i.e. it is somewhere in the middle. As far as counting on the lubricant used to stabilize the speed of the platter and reduce pulsing of the motor by creating drag, that is a piss-poor design. Not only do all lubricants break down over time, but their viscosity varies with both ambient and internal temperatures. As such, i can see the need to use a specific type of lower grade lubricant as a "band aid" IF the product was poorly machined and / or lacking in design integrity ( poor speed regulation / stability ). If a product is truly well designed and well machined, the name of the game for any bearing type device would be the lowest friction possible. Sean > |
Teres: If your stylus is centered in the groove, there's minimal drag. The only "friction" that the stylus should encounter would be converted as motion in the cantilever, which energizes the cartridge and is converted to electrical impulses known as music. If the stylus is exerting massive amounts of drag i.e. enough to cause the platter to destabilize rotational speed and effect the stability of the motor / speed regulation system, you're vinyl system is in really bad shape. Then again, i keep forgetting some very important facts here. Most of you folks are using pivoted arms that are only in the center of the groove at two points per record side. I guess that if i were dragging my stylus sideways through all of grooves except for a very few, i'd be more concerned about this. Then again, one would think that they would be more concerned with the damage being done to their irreplaceable vinly recordings than to how much speed variation such an arrangement was causing. Outside of all of this, i guess that one should contact the manufacturer of their table. They should know how well their products are designed and whether or not they need some type of "band aid" to work properly. Sean > |
Herman: If a diamond can cut through hardened glass, what kind of "drag" could there be slicing through pre-cut grooves of soft vinyl? If there's enough "drag" there to cause speed irregularities, there's something wrong with the design of playback device. Not only should there be enough inertia built up in the platter to more than compensate for any type of variance in drag caused by the stylus, the motor and speed regulation system should detect these variances as fast as they occur. The only reason that the motor / speed regulation circuitry couldn't correct quick enough is if it was of a poorer design with slow circuitry and / or there was too much drag on the bearing from using a heavy, motionally stable platter and too weak of a motor. As such, reducing the drag on the bearing would be beneficial in terms of both bearing and motor life and should contribute to faster response times from the speed correction circuitry as ANY drag would be noticed faster. Like i've said before, what passes for "high end" typically only means "high price". You can throw money at a product but that doesn't make it well designed. Friction is the enemy of any well designed product that requires motion. After all, friction generates more heat, causes more wear, requires more force and is nothing more than lost energy. Sean > |
Herman: If the stylus wasn't "scraping" its' way through the vinyl troughs, it wouldn't be generating heat at the tip. That heat is wasted energy due to unnecessary friction. It's pretty simple when you break it down. Amplitude modulations in the vinyl surface should simply produce vertical displacement of the cantilever. This vertical displacement is the result of energy transfer, which produces voltage from the cartridge and the accompanying music from your phono stage. There is some horizontal deflection also as there are various amplitude passages that occur in one channel that don't occur simultaneously in the other channel. This is what gives us output in the individual right / left channels. As such, the "friction" between the stylus and the vinyl groove comes from the fact that the stylus is NOT centered in the mass majority of grooves. As a result, the cantilever is constantly being twisted rather than being pushed up and down on loud to quiet passages or side to side during left to right / right to left signal changes. This is how records get "worn out" due to the "cutting action" of the diamond "dragging" across the sides of the grooves, not through the center of the grooves. If you can align the stylus in a fashion that it stays relatively centered in the grooves, you'll find that surface noise is drastically reduced and stylus' will last a LONG time. Then again, you can't ever hope to achieve this type of performance from a pivoted arm due to the very nature of the design. As to your comments about servo's, they can be made quite fast and quite good. Compared to a pivoted arm that can only be correct in two places ( at best ) along the entire side of an LP, i'll take a well designed servo controlled linear tracker any day of the week. I would rather have something that was "very close" most of the time as compared to something that was "rarely correct" at best due to the law of averages. As far as introducing more drag to compensate for other drag, that sounds like complimentary colourations to me. Neither is "right", but you end up with something that is bearable. It's not necessarily "good", but it works. Like i said, you can throw money at a design, but that doesn't make it good. It might be better than others of similar design, but that doesn't make it good. It just makes it slightly better than "poor" because it isn't quite as obvious due to the blatant errors being covered up. Sean > |
El: Speaking of shock's and servo's, one might find this servo-related suspension system designed by Bose to be of interest. I would suggest looking at the whole article and then watching the videos at the end. Quite impressive if actually performed / tested in an even-handed manner. Herman: My specific choice of wording may have been poor and lacking in continuity, but i meant the same thing. When a diamond is "scraping" or "dragging" across the side-walls of the vinyl, it IS "carving" through the vinyl. This is what causes sonic degradation, groove distortion, stylus wear and heat. As far as stylus temperature goes, the cantilever will act as a heatsink for what would be "normal" drag. That is, the type of material that the cantilever is made of will depend on how efficiently it absorbs and radiates heat. After all, there IS going to be a certain amount of drag / heat as the diamond and the vinyl are in direct contact ( hopefully ) and the vinyl is in motion. More modulation "should" simply cause more vertical deflection, which "should" be transmitted strictly as mechanized energy. This generates electricity in the motor structure of the phono pick-up, not heat at the tip from "scrubbing" due to mis-alignment. How efficiently this mechanized energy is converted to electricity without loss will depend on the rigidity of the cantilever, the tracking ability of the cartridge, how "correctly" the cartridge / arm interphase is set up, etc... YES, there IS going to be drag in a vinyl system. The key here is to minimize it and have a system that maintains proper operating speed with high stability. If properly designed, the platter will have enough inertial mass and be balanced well enough to maintain a steady speed even with varying levels of groove modulation. The motor should have enough torque to "muscle" the mass of the platter as needed and the system monitoring the speed should check and update often enough to make the proper adjustments without the speed varying too far out of tolerance. Reducing the friction at the bearing simply means less energy lost i.e. closer to perpetual motion of the platter due to less "rolling resistance". Once this has been addressed in the bearing / platter support structure by using proper machine tolerances and the proper lubrication, the platter spins freely, both more consistently and longer due to less drag. If the machining was well performed and the lubrication itself doesn't introduce drag inconsistincies due to surface tension ( how "slippery it is" ), the result is a reduction in frictional losses. With less frictional losses, we need less error correction from the speed monitoring device to come into play. This in turn reduces the vibration from the motor as it isn't lurching or clutching due to the reduction in speed adjustment needed. The only drag involved in such a system would be that of the centered stylus in the groove, which inertia from the weighted platter should pretty much take care of most of the time. Since we haven't been able to design a "lossless" mechanical system, the motor and speed correction devices are still needed though. That's because the tracking force of the stylus is introducing loss into the system along with the minimal amount of drag that we can't get rid of in the bearing. Obviously, the less friction in the bearing, the less drag / vibration in the whole turntable due to the domino effect of losses & correction involved. Sean > |
Herman: your example of an off-center record is a bit extreme. While this does happen, even a pivoted arm is "wallowing around" in the grooves as it the disc shimmies and shakes in an oblong rotation. There's only one TT made that actually deals with this in a very thorough manner and it is a Nakamichi. The ReVox TT's with the "brick-like" linear tracking arm uses some type of optical sensor that reads the groove spacing and adjusts accordingly. I don't know the specifics of this system, but you can very clearly see the light shining down on the disc from within the "cartridge carrier" ( for lack of a better term ). This was my first linear tracking table and quite honestly, i was not the only one impressed by this $150 Ebay purchase. Everyone that heard it after i set it up in one of my systems commented on how good vinyl sounded. As a side note, Kavi Alexander of Water Lily records uses a ReVox ( as far as i know ). I remember that he was looking for one of these, so i dropped him a line and gave him some background as to the differences between the various models that ReVox made. He was so grateful that he offered me a free disc from his label, but i declined his gracious offer. After all, if we can't help each other out without expecting to get compensated for basic info, we are a doomed breed. Excuse me while i park my dinosaur : ) Sean > |
Herman & El: You guys are discussing something in specific that i'm not really super fond of i.e. servo-driven linear tracker. Based on past experiences, i still believe that such a design has the potential to be better than most conventional pivoted designs. Having said that, my thoughts are that the servo-driven mechanism is still going to be closer to the center of the groove more of the time than ANY pivoted arm over the duration of the LP. We already know that a pivoted arm can only be "centered" twice on an LP. We also know that this figure is based upon optimal cartridge installation / alignment. With that in mind, how often do you think that the stylus is going to be centered on a pivoted arm as the off-center record yaws back and forth? On top of that, you have the inertial mass of the arm following that rotational irregularity, supported only by the cantilver of the cartridge up front and the bearing at the back of the arm. This not only causes the arm to follow that motion with NO form of correction, you're introducing more horizontal deflection into the stylus than should be there. My guess is that under these conditions, the stylus of a pivoted arm would be centered a big fat "ZERO" times on a record like this. That's because even when the arm gets to the point where the stylus should be centered, the stylus is probably going to be being pitched about sideways as the record wobbles around its' rotation. Now how often do you think the linear tracker is going to be out of the center of the groove? Not only can the arm measure and correct for this ( to some extent ), but the arm starts off with the stylus following the grooves rather than pivoting across them? Before answering that, ask yourself how a record is originally cut i.e. with a pivoted arm or with a linear tracking cutting head? Now factor in how that cutting head is driven i.e. with a servo-driven motor. If common sense has any input into your thought process, the law of averages will tell you that it is with the "inferior" servo-driven linear tracker, flaws and all. Pivoted designs came about because they were FAR more cost effective and easier to design and produce, not because they worked better. Sean > PS... Most of the early motorized linear trackers put the money into the mechanics of the table's arm, meaning that the rest of the table i.e. the attention to motor vibration and the platter suspension were highly compromised. The fact that many of the motors driving the platter were also driving the arm compounded the vibration problem, which was already poor to begin with. |
El: I know how the Sony arm works and understand how it is allowed to pivot at the rear i.e. it isn't "anchored" at the rear like the older HK / Rabco motor driven designs. Having said that, even the HK / Rabco has enough "slop" in the arm assembly to allow a certain amount of lee-way should sidewall thrust come into play. As such, i was trying to keep the discussion somewhat "universal" in scope and not just concentrate on that one specific product. There were many other mechanically driven linear trackers out there and that is what i was talking about. After all, the comment pertaining to "why aren't these designs more common in the industry now if they were so good then" was previously used. I was trying to respond to that and at the same time, keep things current with the comments being made about your Sony. Hard to be both specific and general at the same time without some form of confusion arrising : ) Herman: Maybe the Bose servo-suspension is what you need in your car : ) Sean > |
Bose may not have invented it, but maybe they'll be the first to impliment it in a manner that is both effective and user friendly. After all, with all of the profit margin that they make on their plastic products using the lowest grade materials, they can surely afford to invest in quite a bit of R&D. It's obvious that they aren't re-investing the funds that they make off of audio into improving their audio products, so why not shovel it into another line of products all-together? Sean > |
