A new way of adjusting anti skate!
@lewm , I would say I am jealous but I just bought a new set of ski boots and skis. In this cold weather the ski areas can make snow like crazy. One good storm and we are all set. I have to justify the expense:) Do you have another system in your tropical abode? |
I am bewildered. Several points made defy logic. Antiskating has nothing to do with offset angle? I suppose you could say that the skating force is due to proper tonearm geometry of which offset angle is one factor. A straight arm with no overhang has little skating when it is tangent to the groove. A 12" arm with a smallish offset has a lesser amount of skating than a 9" arm with more offset. The water skier outside the wake has created an offset angle. If Wally wants to look at it from a different angle, it is a free country, but looking at it as a function of offset angle is perfectly appropriate. Poorly set antiskating does not affect the volume of either channel and does not move the center image. It effects the groove velocity at which the cartridge will start miss tracking one channel or the other. Miss tracking causes distortion, very annoying distortion. Boy, is it cold outside! Don't forget your gloves and hat! |
@lewm , whether you like it or not lewm the skating force increases with groove modulation which is synonymous with groove velocity. I have explained it as best I can to get it through your stubborn countenance. Maybe AJ Conti can do a better job. https://www.basisaudio.com/ajs-discussion-of-antiskate-forces/ You continually want to mistake groove velocity for linear speed. They are two very separate granted loosely related issues. There are only two coefficient of friction figures for any pair of materials, static and kinetic. The static coefficient of friction is related to the two materials in contact at rest which includes the "stiction" factor. The kinetic coefficient of friction is related to the two materials in motion which is the situation we are dealing with. The kinetic coefficient of friction does not change with linear velocity or what you would have playing a blank record, but it increases with increasing groove modulation which is synonymous with groove velocity. You object to the term groove velocity because it includes the word "velocity." When you see the term "groove velocity" just substitute groove modulation and I think you will be just fine. If not you can object until you are blue in the face but it won't get you anywhere except maybe a visit to the ER and I certainly do not want that so please do not stop breathing. We like having you around to argue with. @nandric , while the skating force might change a tiny bit with stylus profile, other than the prescribed VTF the cartridge has nothing to do with the skating force. |
@dover , The skating force you see on a blank disc is due to raw friction, as Lew understands it and the offset angle. The pull on the stylus is the result of friction plus the energy required to change directions which increases with groove velocity. That "pull" is the kinetic coefficient of friction in the equation above. |
@lewm, you are right that the linear speed of the record by the stylus which decreases as the arm gets towards the center of the record does not change friction. Thus if you had a blank record the friction would be the same anywhere on it. Although it is termed as friction, as groove velocity increases more energy is required to keep the stylus moving. The stylus has to be accelerated harder which would increase the force the groove places on the stylus which would increase friction. This happens momentarily as the stylus is forced to change direction but the additive effect is to increase friction. Overhang has almost nothing to do with skating unless you play the label area. It is almost purely the result of a pivoted arm having an offset angle. Decrease the offset angle and the skating force decreases. A straight arm has no skating. There is a relationship between tonearm length, offset angle and overhang but an offset arm will skate even if the overhang is zero. Try it millercarbon. Set your tonearm so there is no overhang and play a blank disc with your anti skating defeated and watch what happens. |
@lewm , call it whatever you like Lew but the "pull" on the stylus increases with groove velocity (modulation). It is usually referred to as friction but I understand your distinction. According to the equation the kinetic coefficient of friction changes with groove velocity which results in the variation in skating force. Groove velocity does not change over the surface of the record which is why the skating force does not change much over the surface either. |
@lewm, you are using the WRONG definition of groove velocity. It is not the linear speed of the record by the stylus. It is the actual speed of the stylus in the groove which is a direct result of the degree of modulation. The higher the modulation the faster is the groove velocity. The higher the groove velocity the stronger will be the force Friction) pulling the stylus away from the pivot. GOT IT! |
@normb , listening for distortion and watching the cantilever displace as it hits the record are sort of arbitrary. To get a good cartridge to distort requires very high groove velocities that over estimate the AS force required. The cantilever displacement was useful in the days of high compliance cartridges but not with the ones we use today. They are too stiff. Frank Schroders advice to set it so the arm slowly drifts inwards when placed between grooves in the run out section is probably the best low tech way of setting it. The equation I mention above is very specific except there is no one value for the kinetic coefficient of friction. There is a range. Using the Wally Skater and my device are really very simple and you know exactly what you are doing with a very specific target which is reassuring. Then you just forgetaboutit. I have also used my modified gauge to verify that the Schroder method does indeed come close and using the blank record method consistently over estimates the AS force. I did not study cantilever displacement because by the time the cantilever starts deflecting with my cartridge the AS is way off. |
Lew it is headshell offset angle. The reference is to the arm's pivot not the record. The equation works fine. The variation is in the kinetic coefficient of friction which changes with groove velocity. The recommended value is 9 to 11%. I just round it of to 10%. You can not hold the gauge vertical. All that I tried gave unreliable readings this way. I used a 1 to 1 pivoted arm to change the force from horizontal to vertical. The scale sits on the platter as usual. The floating arm which is drifting outward because of the antiskating force is then located against a pin in the vertical arm of the 90 degree lever. The force is transferred to the scale and you have a measurement. The lever arm should place some downward force against the scale which you cancel out with the tare button. The quality of the bearing is critical. Cheap bearings out of router bits will not work. Ask me how I know! I used a tiny, oil free, ceramic ball bearing. You want a scale that measures down to thousandths. I'll email you a picture when I get a chance. |
@luisma31 , I have the HFN analog test record. The problem with this method is in order to get the cartridge to miss track audibly you have to use very high groove velocities. This then over estimates the antiskating required for your average passage. The blank record trick also over estimates the anti skating force because the very tip of the stylus digs into the vinyl increasing the frictional force. Play a blank record then look at it under the light and you will see the spiral scratch. The most accurate way to set your average antiskating force is to trust the math and shoot for 9 to 11% of VTF. 10% is a nice round number. You can do this by measuring it directly which is what I do or spend $250 and get a Wally Skater. It works. It just seems to be a bit much for a few pieces of acrylic and a string. You can get a digital stylus force gauge for $30. But, you have to change the force vector from horizontal to vertical. |
@lewm , You bet. I tried to read vertical with two different gauges and both would not function this way. They have to be horizontal which is why I built the Gizmo the way it is. Don't try it with a cheap bearing. It will not give you repeatable measurements. You have to use a dry instrument bearing. I think it was you who asked where the 10% figure came from and I found out. AS Force = sin(headshell angle) X VTF X kinetic coefficient of friction
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@joenies , I brought up the idea of renting the tools out. Collecting the purchase price of the tools then refunding all but 10% plus shipping on their return. It did not go anywhere. We do have woodworking clubs that fund a single workshop that everyone uses. I suppose you could form an analog club. $50 admission fee and 25 people would do it. I would get the Wally Skater, the Wally Reference and a Smartractor. |
@lewm , I believe the 10% figure came from a Shure study as representing the best average value. I have seen it mentioned in several places. You can probably talk to someone at Wally Tools about it. As far as I can tell it works fine. I set it at 10% and forget about it. I have watched the cantilever with a USB microscope and it does not deviate as it touches the record at three locations so it is certainly in the ballpark. |
The Wallyskater will scare the heck out of most people, kill em dead when they see the price for a few pieces of plastic and some string. It does work but there are easier ways to estimate the antiskating force which should be between 9 to 11% of the VTF. If you are tracking at 2 grams the anti skating force should be around .2 grams at the stylus. The Wally Skater figures this out with a little clever trigonometry. I measure it with my digital stylus force gauge and a little trickery. |
Blank vinyl records are a bad way to do this. The tip of the stylus digs into the vinyl creating it's own groove. Try it and then look at the record under the light and you will see the groove! It will over estimate the amount of anti skating required. I discovered that digital stylus gauges will not reliable measure weight horizontally even with the tare adjusted. But I have created a solution to that problem. Stay tuned. I intend on beating Wally Skater at it's own game!! |
Motown, once you confirm that your tone scale is accurate then absolutely use it. Benjie, The digital stylus force gauge used in the way I described is more accurate than the WallySkater's gradations. It is a far more elegant and less expensive way to do it than a plastic contraption that costs you $250. The stylus force gauge is a lot easier to set up also. drrsytliff, I am not suggesting that you do not use accurate tools for set up. I am suggesting the right tools especially ones that do no stress the budget. I hate to suggest this but due to the tools you are using your cartridge stands a good chance of being out of alignment. |
Audioguy, the problem with that method is, what is slowly. Clearthinker, I agree in theory using the term tangential tracker. Every "parallel" tracker I have ever seen is compromised usually severely to the point that the best of the light pivoted tonearms sound better. However, Reed and Schroder figured out how to do it right. My next arm is going to be a Schroder LT and I will be done with anti skating forever. My thinking exactly wolfie62. There is something satisfying about working to a number vs haphazard ways. The people who are complaining probably do not have a digital VTF gauge. There is general agreement that the anti skating force should be 10% +-1%. This certainly beats listening to a test record and a lot faster:) |
The accepted value is 9 to 11 percent of VTF at the start of the record decreasing slightly towards the center. The biggest variable is velocity (modulation.) The higher the velocity the higher the friction. You can only shoot for an average value. Millercarbon is prone to extremes, "varies tremendously across the record." This makes him difficult to believe. 9 to 11 % is not tremendous. Lewm, anti skate can be adjusted to an extent during play. The geometry of many antiskating devises automatically lowers the anti skating force slightly as the arm traverses toward the center. I used the same method by listening. It takes some fiddling to get it right. This method puts you where you want to be easily while setting up the arm. Psychologically it is nice to work to a number. But whatever. The main point is that you can do exactly what the Wallyskater does without spending $250. It is a product without a market. Rube Goldberg could not have done better. |
