The 'Italian proposition' was: 'mister the pope is impossible but we have a very beautiful cardinal for you.' I wrote this to Raul as a kind of introduction for my question about the 'second best' choice because the Technics 205 mk4 and the AT ML 180/OCC were impossible to get. Two weeks ago I got the AT 180 but, alas, was not very impressed. That is to say that my Virtuoso black with pressure fitted nude line diamond in a aluminum cantilever sounds better. Anybody else with experience with the AT180?
Regards, |
Regards, Fleib: Did you read the copy from the B.A.S. above? It relates cantilever angles differing by almost 25*, the writer seems to suggest that 20-22* is best. I read years ago that cutting angles varied from one machine/producer to another through the mid 70's, however this relates to SRA.
Correct me if needed but IIRC, in 1974 (+-) the RIAA adopted 22-24* as standard VTA & 92* for cutters. Any thoughts on why (other than standardization) the writer places so much importance on the angle of the cantilever? Yes? No? Just curious.
BTW, for those interested in such, lots of charts, graphs, specs, hints & testing procedures in the two "turntable clinic" segments linked above.
Peace, |
Regards, Nandric: Having a "wry" sense of humor refers to a dry or ironic humor, your post was delightfully endowed with both. If I may remind you of your reference to the VdH warning about destroying records through excessive AS? Observing the orientation of the cantilever is a reasonably effective method of verifying this is not a concern.
"Reading between the lines" refers to a situation when there are inferences beyond what has been actually written or said. An example of such might be if someone were to listen to my ancient rig & then say "I've never heard anything that sounds quite like that". ;-)
As to "authority", I confess there are occasions when I reserve the right to make up my own mind. Nikola, I frequently fail to remember that not all contributors on this forum are familiar with American idioms. Please forgive my oversight. Peace, |
Sometimes a slightly skewed cantilever can be corrected by using max VTF and corrective AS, in opposition to the skew. I've successfully done this a couple of times. My results indicate you must catch it early, before it gets extreme. Sometimes it doesn't work. I'll only suffer with that on few old records. You can also physically move the cantilever with your finger or plastic tool, to see how bad it is. With hi cu carts sometimes a small angle is really no problem or easily corrected.
Timeltel, maybe we can put this behind and move on? Regards, |
Dear Professor, I do try to be humorous and I can assure you that this is not an easy task. But it is all in the game because succes is in no way quaranteed in advance. However I am not aware of any 'wray Balkan humor... between the lines' which is any way connected with the 'cantilever deflection as the arm is queuded down'. I never used this kind of expressions in my life, not to mention in this thread. As Fleib already mentioned you are ascribing some statements to persons who deed not made them while I also had the impression that you are not a careful reader of the post of others. You may have some authority problem but I can assure you that I am totally insensitive for any kind of authority whatever. To me only the statements made are relevant independant from the question by whom they are made. That is to say provided that I understand what is stated.
Regards, |
Hello timeltel yea i to believe that horse needs to be put down.
Havent given p8e a spin as of yet. Im stuck on acutex 320 and right now ELP Pictures at an Exposition nice UK pressing is most certainly pleasing the senses.
Enjoy Mike |
Regards, Stltrains: My last (ever) comment on AS. Fleib, as has Nikola (between the lines of his wry Balkan "humor"), suggest that an inspection for cantilever deflection as the arm is queued down would be a good idea. There was a photo offered on A'gon several weeks ago, the cantilever was permanently skewed from incorrect AS. No recollection if it was from too much or too little.
Finally took the P8ES out of service, listened to three sides of Jeff Beck "Rock 'n' Roll Party", excellent quality vinyl but no "live recording" ambience. Back to the Signet TK7LC, fell in love (or lust) with Imelda May singing "Walking In The Sand". OoWhee!
Peace, Love & Barry Manilow |
Regards, Raul: From the Boston Audio Society, 08-04-'80, this may be of interest : "Bauer in the early '60s,--- found the VTA of most cartridges too high (average 28 o ) to match the then current 15 o standard. With the change to an 18 o standard, matters were moved in the right direction, but the average remains too high. A few notable exceptions occur among the data: cartridges measuring 20 degrees or less include all the Denons, the Audio Technica AT-15Sa, the EMT, an Ortofon MC-20 that was tracking at 1.75 grams but not one tracking at 1.45 grams (and not the Ortofon moving-magnet models), and the Stanton 681EEE (but not the 881S). In addition, a Signet TK-7E and an NAD moving coil were around 22 degrees. Shure models measured 28 to 32 degrees, and the Sonus models were the worst at 32 to 38 degrees. Note that tracking force changes the deflection of the cantilever, and therefore the VTA. Accordingly, Table 2 gives both VTA and tracking force. The audibility of changes in VTA is still under argument. The Sonus cartridge in sample 24 had 0.8% IM distortion at 32 degrees and 4% at 16 degrees. Whether this is significant on musical material cut at normal levels is unclear. It does not predict the subjective effect claimed by believers in the critical nature of VTA, namely that too high a VTA produces a bright, harsh sound while too low a VTA makes the cartridge sound dull. It is nevertheless interesting that the moving coil cartridges, which have a reputation for smoothness and transparency, have as a class much lower VTA than most of the moving magnet designs, although VTA is not the only possible explanation." Considering the usually meticulous reports from the B. A. S, that SRA is not mentioned is curious. Both "turntable clinic" edition are worth skimming over. http://www.bostonaudiosociety.org/pdf/bass/BASS-08-04-8001b.pdf, pg. 24. and concluding: http://www.bostonaudiosociety.org/pdf/bass/BASS-08-05-8002.pdf here. Peace, |
All one other note that eric shared on AS. Notice the arm as it leaves the last grooves and starts on the open travel. The arm should appear to almost slow down and track slowly to the lockout. Between this and more acute speed across the entire record seems to put AS in the ball park.
The readings on wally skater helped with visual and parallels items above.
For the simple minded and hopefully not to arrogant to learn something new. mike |
Dear Lew, The Dutch are collectivly convinced that the Germans have no sense for humor. However I deed find some 'high level' contra examples: 'Wenn Theorie und Praxis ubreinstimmen dan sind sie wahrscheinlich beide falsch' ( If theory and practice coincide then both are probable false). The other one is: 'it is so easy to refute a philosopher the only thing one need to to is read some other'. I myself unconciously acquired Marxian ideology but since I discovered Frege I am only wrestling with statments made (aka their logic).Regarding the SF. Years ago I solved the problem with the help of a groovless LP side. You can see with your own eye how the centripetal force works. I got then with my Ortofon MC 30 S + FR-64 S 90 micron without any distortion from the R channel (aka the buzz). This result made me a happy as well as a proud man. But some time later I come the warning by Van de Hul across. The mesage was : you will destroy your LP's this way. Well since then I have no idea how to adjust my SF. I put 4 of those O rings on my Triplanar and pretend to have solved the problem. Pretending btw seems to be a very important social skill.
Regards,
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Timeltel, You quote me out of context, not even a complete sentence, and change the meaning. It wasn't a command, it was a request. You omitted the word please. ""address further comments on this subject to someone else." is not exactly what I said. I believe that you also attributed statements to the wrong person once or twice. I don't want to hassle about this nonsense. I'm interested in concepts or finding out about specifics, like carts I've never heard. If you're not sure who said something, perhaps it would be more productive to talk about the concept, rather than who said it. This is just a suggestion. I see you're an experienced poster and not a noob. You're also a skilled writer and that's why I sometimes find your approach objectionable and counterproductive. If I made a reference/joke that you find snide, it wasn't intended to make fun of you and I apologize if you took it that way. Funny, I feel the same way.
I have a working knowledge of AS and and basic understanding of the forces involved. What would interest me is techniques for modifying arms for more precise application of AS, especially for diff parts of the record. The Unitrac arm is designed to be mounted so the pillar (not pivot) is 56 degree angle between spindle and rest position. If not, AS calibration is affected. Isn't that interesting? It really doesn't matter if centripetal force is responsible, or you need Susskind to explain. It would be nice to know, but not as important to know whether it's an earthquake shaking the house or a bus going by. Regards,
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Dear Nikola, It may comfort you to know that in the one course in Philosophy that I took in college, I had a very serious young Swiss professor who was very strong on Martin Buber (I and Thou) and Kant. I know that I read The Critique of Pure Practical Reason, and I wrote a paper on it which is still in my possession, somewhere. I remember more about Kierkegaard and Sartre and read them independent of course requirements, for years, because like many in my generation, I decided I was an Existentialist. I did not then realize that consciously acquired labels often lead to permanent ideologies. Thus, while I believe there is a skating force, at heart I don't give a damn. |
Dear John, There are two different reactions possible in the case of an succesful 'experiment': Heureka! for the theoretical kind of guys and 'it works!' for the practical kind. The last mentioned kind may not care about the question: why? But even if they deed it would not result in some 'theoretical insight'. There is this division of labour you know. Regards, |
hello just a few things noted by having the approximate amount of AS added to my micro. speed across the lp is constant and thats a real good thing. and maybe a good way to have an idea that your AS is set correctly. music is solid wide full tight and just sounds great. additional fine tuning on the fly totally removed sibilance. i think i like this AS what a novel idea. just kidding of course this discussion has been informative and another of those dont rap it if you aint going to get up and try it.
i should get a get out of jail free card for my professing that AS was not needed due to having applied anti skate when i thought there was none.
my triplaner has self inflected wounds and will be taking a trip to the land of lakes later on today. tre as mentioned one of the best in audio.
rock and roll is here to stay mike |
Hello Raul and Stltrains,
With a fair amount of trepidation I ordered two NOS Empire 4000D/III original styli from the Bluz Bros. and that's exactly what I got. Thanks, they had both the original (brass arm) and the Gold styli and without your knowledge and information I would never have known what to ask for.
I think when dealing with the Bluz Bros. it is important to be very specific about what you want and ask lots of questions about what they have. A fellow named Alan, "the tech guy" was extremely helpful and knowledgeable. He told me a story about one customer who sent back the brass arm model to exchange for the one pictured on the website.
Finally I get to hear this cartridge! It came with an Empire TT but the original stylus was broken and I had been using an Astatic D/II replacement; not bad but nowhere close to the OEM Empire D/III. Thanks Again!
John
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Lewm,
I would like to read your ideas, but I can't seem to find away to email you via this site. Age is telling. If you like, you can reverse the situation and email me, or contact me through the odyssey tonearm blog. John |
Hello Nikola, Would you not agree that once a practical experiment takes place, some sort of theoretical position must follow? This must be the case for all of us to some extent unless the next experiment is carried out on a purely random basis.
And that theoretical position then informs the practical.
Regards,
|
There are 'theoretical'- and there are 'practical' reasons. The old Kant wrote two separat books about that. For the most of us the practical issue is the only relevant one for the obvious, uh, reason. We are not able to participate in the theoretical dispute. However from the theoretical dispute we can deduce that not much help is to be expected from the theoretical guys. Do it yourself or trial and error method is what we should continue to do.
Regards, |
John, Timeltel and I were discussing the issue you bring up just today by private email. Send me a contact, and I will try to respond to your last sentence. I have a new take on why it is possible that for some tonearms and some cartridges and probably "some" music, use of AS may not be needed, as many good listeners do report. |
"address further comments on this subject to someone else."
Oh no, Fleib, that's not how it works. An open forum, I'll address whom I please. However, it might be best to not address further comments to the other on any subject. No noob here, tired of snide remarks, your call.
Sheesh.
(All else, apologies, and of course,)
Peace, |
Lewm, Timeltel, Fleib, et al
Why not start a separate thread or continue and existing one rather than drop the subject?
There is so much misunderstanding around this subject and, I am sure, so much still to learn regarding why it causes so much disagreement as to the physical versus perceived aspects. And that can only happen when the issues are discussed and argued out.
I have my views on the subject, and they have changed as time has gone on. I have to say, though, that the basic principles and causes were well known long ago and they haven't changed.
What is interesting is why some consider that skating forces do not need to be compensated for, because the corollary is that one side of the groove has less VTF than the other. John
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Fleib, The "basic vector", if you refer to the torque (i.e., angular force) of the turntable motor that is applied to the LP grooves, is indeed in the clockwise direction. But the force that causes skating is the friction between the stylus and the groove walls, which must always be in the exact opposite direction from the motor torque vector, i.e., anti-clockwise. The friction force opposes the motor force, IOW. The work done on the stylus tip by the motor via the groove interface is dissipated as heating of the groove walls.
I am going to bow out of discussing this subject further here, because it is probably boring to others, but if anyone wants to discuss it further via email, I am happy to do so. |
Timeltel, I said I wasn't sure about CENTRIPETAL force. I still don't see tangency or lack of, as causing skating. Must you be so emphatic? I'm done with this. Please address further comments on this subject to someone else.
fleib |
Regards, Fleib: Copy/paste from your friends as Wikipedia: "a force which keeps a body moving with a uniform speed along a circular path and is directed along the radius towards the centre. Isaac Newton's description was: "A centripetal force is that by which bodies are drawn or impelled, or in any way tend, towards a point as to a centre."
From Vince Calder, an educator with the Argonne National Laboratory: " When the trajectory of an object travels on a closed path about a point -- either circular or elliptical -- it does so because there is a force pulling the object in the direction of that point. That force is defined as the CENTRIPETAL force. It has not been more simply, or directly stated than by one Isaac Newton in his famous "Principia": ("IN ANY WAY tend, towards a point as to a centre). ""The term CENRTIFUGAL force appears to have come about because of a mistaken perception that there is a force that operates in the opposite direction as the CENTRIPETAL force. But that is a misconception. The "pull" is the force that has to be applied toward the center."
If a screw and a suitable material are turned in opposite directions, the threads will draw it into the material. The size of the screw, the constituency of the material, or wether the screw is held stationary while the material is turned against it makes no difference, the principle is constant.
An arm with added overhang will travel towards the center. An arm with zero overhang will encounter equal opposing forces at the spindle, it's movement will stop when that condition is achieved. An arm with negative overhang will tend towards the rim, it responds to centrifugal force. In the most elementary terms, regardless of size, shape or the nature of constraint, if an object is placed on a rotating surface, it will move inwards, outwards, or reach a state of balance at some point in-between.
The discussion is tending towards unproductive quibbling over terminology. To say that the observable phenomena of skating is subject to the influence of various vectors is not inaccurate, to state that by definition the concept of centripetal force encompasses those descriptions is also true.
A thing either is, or it is not. Adding qualifiers (planet) to the time honored definition is somewhat like the lady's assertion that she was "almost a virgin". Ya'll carry on.
Peace, |
Lew, The basic vector is tangent to the groove in a clockwise direction. This is further complicated by the pivot/offset angle thing. Please read the last paragraph under Arm Systems (below). I think that's it in a nutshell. Beyond that you'll have to consult your friendly neighborhood physicist. Further than this is beyond my current understanding. Maybe the Prof can enlighten us further. I don't know. At this point I'm more interested in results, measurements, and techniques for optimising sound. http://en.wikipedia.org/wiki/Phonograph#Arm_systems
Regards, |
In my scheme, the actual force generated due to friction between stylus and groove and the lack of tangency of the stylus tip to the groove (at all but two points on its arc across the LP), has a vector that is constantly changing in magnitude and direction, but the direction is always somewhere between the line drawn from the stylus tip to the spindle and a line drawn from the tonearm pivot to the stylus tip. The skate force vector is always directed away from the stylus (as you say) toward an ever-changing point within those two confines. However the stylus cannot move in that actual ever-changing direction, because the mechanical stiffness of the tonearm prevents it. Instead, the stylus moves or can move only toward the spindle, along its permitted arc, as determined by the location of the tonearm pivot. A lot of words, but precise language is necessary.
I think Timeltel (or you) was contending that this is not a true centripetal force, and I now agree. Its origin is not that of a true centripetal force as described in Newtonian mechanics. (Gravity holding a planet in orbit around the sun, for example.) |
correction: I should have said, Both those directions are away from the pivot or cantilever line, not exactly toward the spindle. |
Lew, IMO the most elegant and concise description already supplied by J Carr: **What causes skating forces is the fact that, with offset-angle tonearms, the LP groove pulls the stylus in two vectors at once. One vector is from the stylus to the tonearm pivot. The second vector is along the offset angle.
These two vectors synthesize to produce a third vector that pulls the stylus inwards, toward the platter bearing. It is this third, synthesized vector that we call "skating force" or "side force".
Since skating forces are comprised of the drag on the stylus from the LP groove, they vary depending on stylus profile and groove cutting levels, and from what I have seen, the skating forces also vary according to the instantaneous groove radius. (If you can find an Orsonic SG-1 "Tonearm Side Force Checker" it will allow you to plot the curves).
If I recall correctly, if you can manage to cancel out the groove amplitude-dependency component (by using a constant-amplitude test LP), the side force curve ends up looking fairly similar to the tracking error curve for the particular tonearm alignment that you have chosen.**
I think offset and not overhang is the cause. If the offset is 23 degrees, wouldn't the arm be tangent when it gets 23 degrees away from the null? (not that it matters) If you offset a cart on an arm with no overhang, there would still be skating.
I think we can agree that skating exists, regardless of theory. We all agree that it's friction pulling the stylus in 2 directions at once? Both those directions are away from the pivot or stylus, not exactly toward the spindle. Regards, |
Headshell offset does allow for tangency at two points across the LP surface. Flieb said that, and I agree with that. It was my error not to include that in the analysis. My model would predict that at those two points, there is no skating force. My explanation was incomplete but not wrong per se. I should have said "a straight line from the pivot to the stylus tip" is side a in the Pythagorean Theorem model, and is never tangent to the groove. Dover, tangency would always occur at TWO points on the LP surface, if the cartridge is properly aligned according to any of the conventional algorithms. You can't do better than that.
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All my statement on manufacturers attempting to do as if i understand correctly with my AS research is the attempt is to add AS gradually as the cartridge tracks the grooves to its end. I cant and should not have vouched for triplaner being in that number until i get the wiring artificial AS resolved. But as for my micro the visual proof that i can see with my own eyes clearly shows increase in AS at the beginning middle and end of an lp.
Im not real sure if theres a mathematical phenomenon that can explain this reality. But if there is im sure you will read it here first.
Its a real good day in my neighborhood cause i finally has a true grip on AS. Its a good thing and contrerary to past knowledge here needed for superior playback and sound.
Mike |
Lewm, Your Pythagorean theorem explanation seems flawed to me. If the cartridge is twisted relative to the tonearm then this explanation is irrelevant. If we assume the diamond is correctly alligned in the body, and the cartridge is angled to provide no tracking error at one or two points then a "tangency" can exist at one or two points. In other words you can achieve tangency at at least one point without a right angle triangle existing as long as you can draw a perpendicular line across the stylus and hit the centre of the spindle. |
Regards, Pryso: Skating force is relevant to the audiophiles position. ;)
Before Lew explodes: First, the speed of a revolving object is greatest at the outside perimeter. If the rpms are constant, velocity as measured in inches per second (ips) decreases as the center is approached. Stylus friction, groove modulation, skating & ALL the relevant etc.'s are contingent to ips's.
As it applies to our concerns, let's change some of the parameters. We'll tie the end of a rope to a point anchored outside the rim of a merry-go-round. Imagine that our volunteer audiophile has given us just enough rope to hang him, err, to sit him, harnessed to the other end of the rope just past the capstan of said ride, now give it a clockwise spin. If he is facing the outboard anchor he will be subject to forces from two vectors. The first (from his perspective) will be from front to back. The consequence is a tensioning of the rope. The second will be coincidental to the fact that his position is somewhat past the capstan. As the ride's platform continues around in its rotation there will also be an additional influence, this from his right to left. In this case there is a lateral force originating from his right, as the platform slips beneath him he will be drawn left towards the center capstan. As this occurs and due to the reduction of the platform's inches per second of travel as he is drawn closer to the capstan, the influence of this lateral, or centripetal, force will be progressively reduced.
Peace, |
Dear Fleib, I love you, but you have forced me to get even more pedantic than I have already been. There CANNOT be ANY points on the arc traversed by the stylus wherein the (pivoted) tonearm is perfectly tangent to the groove, and here is why:
When the tonearm/stylus is tangent to the groove it must also be perpendicular to the radius of the LP. Correct so far? When that condition pertains, then a line from the pivot to the spindle (the P2S distance) must also constitute the hypotenuse of a right-angle triangle. OK? When or if that is ever the case, then said right angle triangle must conform to the Pythagorean theorem: a-squared + b-squared = c-squared, where "a" is the tonearm effective length, "b" is the distance from the stylus tip to the spindle, and "c", the hypotenuse, is the P2S distance. Well, we already know that all conventional pivoted tonearms are installed such that there is stylus OVERHANG, which must mean that "b" in our equation is always greater than "c". Thus the Pythagorean Theorem can never be satisfied. Ergo, tangency never happens. Which is why we always have a skating force. I can go on to explain the direction of the vector of the skating force, if you like. But it's easier to do that with vector diagrams, which are not possible here.
Also, I say again, the term "centripetal force" is naught but a description of a particular kind of force. In a way, you are correct when you say that there is no centripetal force on a stylus. The force that is generated due to the geometry is actually always at an angle that points more or less to the left rear of the turntable starting at the stylus tip, not to the spindle. But the stylus cannot move in that direction due to the mechanical stiffness of the tonearm, so the force vector gets expressed in the only possible direction for the stylus to move, which is inward toward the spindle via rotation of the tonearm on its pivot.
Timeltel said it first in its simplest form: "Skating force is due to stylus overhang", or words to that effect. It took a few days to dawn on me why that is correct. |
That's what I was talking about regarding skating. The force will vary depending on position and stylus velocity. I think the idea is to find a setting where you get a centered cantilever at moderate velocity at different points on the record. Most AS controls are calibrated for a percentage (15 to 20% ?) of VTF. One problem is that old spring loaded controls can be way off. Also, modern stylus profile might require greater AS. The Wally Tractor sounds like a cool device. Sighting from the front at different positions on the record is also effective. Looking at output levels on an electronic device is good. Because there is no perfect setting for all occasions, I try to find a position that sounds centered with a mono female vocal with a small band behind her. This is like my normal fare only I don't listen to all that many vocals. I can't help but to sight the cart from the front. If you can get in that position you'll be amazed at what you'll see. With even lighting and being directly in front, the angle of the cantilever in relation to the cart body is obvious. Do this at three places on the record and it will get you 90% of the "perfect" setting. May the anti-farce be with you. Sorry. Regards, |
Hi Mike, can you explain how AS is built into an arm to vary as the cartridge moves across the record? The most common mechanism I'm familiar with is the string and weight, attached to pull the arm counter to the skating force. I don't remember much from physics so does that change as the arm moves across the record and the distance of the weight from its support (fulcrum) shortens? I believe other arm designs (your MS?) utilize a spring for the counter force.
Banquo363, setting AS equal (on a scale marker at least) to VTF is a long standing recommendation, including by many manufacturers. More recent thinking suggests that AS should be 2/3 of VTF. Thus a simple example with 1.5 g VTF, set the AS scale to 1. I don't believe any of the AS scales are intended to represent specific weight so it is not 1-1.4 grams. |
The manual for my Technics epa 100 mk2 says to set anti-skate to same number as vtf. For my mm carts that's between 1-1.4 grams. Is this crazy?
I can't hear a repeatable difference between .5g and 1.5g. For this, I'm more worried about record and stylus wear than sound quality. |
Pryso depending on the arm that factor has been included in the design. Both my triplaner and micro have that feature. I am not pushing wallys tools but his wally skater will show AS and its percentage at any point on your lp. Mike |
Hey guys, I can't add anything to the why? or how? of AS, only a further question.
I recall reading some years ago about Thorens' research on skating force and their finding that correct AS would actually change as the arm/cartridge moves across the record. If that is correct, how can we best compensate for skating force? Should AS be set for a mid-point on the LP (thus an average) or should it be adjusted within the last third (if that is subject to greatest distortion due to the shorter radius)?
Sorry if this muddies the waters even more. |
From physics class: "Any motion in a curved path represents accelerated motion, and requires a force directed toward the center of curvature of the path. This force is called the centripetal force which means "center seeking" force. The force has the magnitude." Clearly in our case this force is friction and the direction is defined by the groove and the fixed arc of the arm. Also: "Centripetal force is a force that makes a body follow a curved path: it is always directed orthogonal to the velocity of the body, toward the instantaneous center of curvature of the path." In this case the force is not what makes the stylus follow a curved path. That path is determined by the stylus and pivot position being fixed. That's why I have doubts if it really is centripetal.
"What causes the (centripetal) skating force is the fact that conventional pivoted tonearms are never tangent to the groove wall. Because of that there is always a force vector generated that is in a direction determined by the angle between tangency and the actual angle of the tonearm wrt the groove." IMO this is totally an unequivocally wrong. 1)There are two points along the arc that are perfectly tangent. Does skating stop for those points? 2) Friction keeps the tip in the groove which determines direction. Is it dependant on alignment or being tangent, or can there be friction and forces regardless?
"The forces exerted by the groove wall would be present for any and all styli riding in any tonearm, even linear trackers. (I start from the fact that in an air-bearing linear tracker, that force is the only force acting on the stylus tip, yet we say that linear trackers do not induce a skating force.)" Most linear trackers AFAIK, use VTF and friction to keep the stylus in groove. Your point supports what I'm saying. The only reason a pivoting arm and skating could be considered centripetal is because the path of stylus is curved, the force is toward the center, and it's accelerating.
It was stated by physics type people that the vectors of force derived from friction, by the stylus, is what causes skating. Centripetal force is usually applied to spheres orbiting a larger body, or twirling a ball on a string. It would also apply to a car spinning out on a curve so maybe it applies. Perhaps if you find the answers to these questions, we'll know. Does a pivoting arm with no offset, skate? If a linear arm is not tangent at some point, does it skate at that point? Why, because of lack of tangency or no offset? Regards, |
Dear Fleib, You wrote, "Regarding the theory behind AS: I really don't know if centripetal force is the primary cause."
Skating force IS a centripetal force. "Centripetal force" is just a descriptive term that tells us that the vector of the force is directed toward the center of a circular path of a body in motion. Centripetal force does not "cause" anything. What causes the (centripetal) skating force is the fact that conventional pivoted tonearms are never tangent to the groove wall. Because of that there is always a force vector generated that is in a direction determined by the angle between tangency and the actual angle of the tonearm wrt the groove. This force is per se not centripetal, but we only "see" its centripetal component because the mechanical stiffness of the tonearm translates the actual force vector (which is always changing in direction and magnitude) into one that IS unidirectional and is centripetal. (The tonearm only allows free rotation in one arc, directed toward the spindle, i.e., "center-seeking".)
As I see it, the skating force is a force over and above that which is exerted on the stylus tip by the grooves to guide it in a spiral toward the center of the LP. That force by itself would not induce the tonearm to skate. Anyway, that's what I am thinking at this point. The forces exerted by the groove wall would be present for any and all styli riding in any tonearm, even linear trackers. (I start from the fact that in an air-bearing linear tracker, that force is the only force acting on the stylus tip, yet we say that linear trackers do not induce a skating force.) |
Mike, nice to read about your recent experience with AS and your arms. As per Raul's request, your post was an empirical description of consequences or benefits. I took it for granted that the goal is to get a proper image and center. Bass performance is also impacted because excursions between groove walls will be affected by side forces on the arm. There are programs available now (like Feickert) to see performance plots on your PC. You could also see azimuth at the same time. Someone on another former has the Feickert program and wound up using a mono record. I think David knows something of what's available and might be able to recommend one.
Regarding the theory behind AS: I really don't know if centripetal force is the primary cause. The arm swings in an arc and it is accelerating, so maybe it is. Then, is the additional force from offset a Coriolis force? [Joke] Point is, it's moot as far as empiricists like I am concerned. I know that conical styli use friction to stay in the groove and are subject to the same considerations, possible less so than other types. BTW, a .2 x .7 has smaller contact area than most conicals. I don't think tangency has much to do with it. Why would tangency have an affect on these forces, would it negate friction, the primary force?
For practical considerations, adjusting AS, there are two primary considerations to take into account. If you adjust for the loudest passages or highest velocity on a test record, you'll have too much, most of the time. I find a mono female vocal, most useful to get a center image. Regards, |
well i have my answer and to those using a triplaner you could have wire interference with your anti skating settings. the wally skater is a cool vinyl tool that gives you a percentage of skate.
with my micro all was as wally has stated in his instructions of WS tool. without antiskate theres none in fact negative numbers. when AS is set on the red line the percentages fall right in to what wally advises.
now with triplaner the only arm ive used i 4 years or so its a whole different story and explains why i did not need to add skate to mine for good sound. with just the lever only no weight added i am getting what wally recommends front middle and rear of the platter. without any applied skate the percentages are only off by 1 or 2. as emeril lagasse says bam, there it is.
i feel better playing around and learing something today. and it was a good mardi gras right here at the house.
now show your xxxxxs mike |
alas the slightest amount of AS applied to my micro arm can be added without me thinking theres a lost of my dearest SOUND. what i am getting from the added AS to playback is tighter bass and those sounds with in the image of the sound stage are tighter also. i would say thats for the better.
i just added the AS assy back to my triplaner not sure if just the lever is to much. dont know how herb came up with the 4g weight supplied with TP but it seems way to much no matter where located on the lever but who am i to question his design and im not, love the arm.
i am one who promotes getting off your butt and trying different things with our vinyl playback and systems. i was wrong to think AS was not necessary and thats getting back to triplaner cause i used the supplied weight rubber donuts brass washers and more and was happy with out any AS. the way the wiring passes thou the arm tubes and comes out of the arm tube could play a part in applying some AS on triplaner possibly.
i bought a wally skater years ago and never removed it from its wrappings. going to give it a good look over/use compare that to my ear method adjustment and hear where that takes the only thing that matters to me SOUND.
Timeltel on those moodys tracks theres not much of a difference in locations/sounds with as you mention there position in the soundstage with or with out AS here. sound wise Thomas flute is woodie and wonderful i sure miss him touring with the band. Norda Mullen who took his place is excellent and looks a lot better than ray.
throw me something mister mike |
Regards, Dgob: You are being too kind. I thought the discussion was educational, entertaining and on occasion deliciously nonsensical. Everyone else made points to be considered and there's still some difference of "opinion" evident so for now, "the jury is still out". I took one look at the fomulae offered by Sony and decided my once fair math skills had atrophied. If Lew can wade through it and make it sensible to the rest of us, I'll be even more impressed with his capabilities.
As to the nonsense, I found this bit "somewhere". Sorry 'bout that.
"Poem" by Henry Gibson
Tonearms swing like a pendulum do. AS calms its travel from rim to spindle through. Take it away and then to late you'll scowl, The inner groove your stylus did plow.
Centripetal force Newton first knew. Then it was overhang Your channel balance further to screw. Magnets and springs, weights depending from a string Unkindly tension and torsion these will make true.
An evenings' journey of Pythagorean jazz, Repetitive Mantras of rock, perhaps something soulful and blue. The mathematical progressions of Bach, this some say will do. Introspection found in music, just think it through.
All said and done in that vector stew, Listen to your favorite, you'll hear it anew. Dial in your anti-skating and AS always, May the force be with you!
Peace, |
Happy Mardi Gras!!!
http://experiencemardigras.com/
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Dear Fleib: As you I had experiences with Adcom and SAE but was many years ago and what I remember due not only to the time already pass but the differences in my system my opinion about is almost useless.
In the other side I can't remember any first hand experience with the Coral one ( direct to Coral. ).
From some months now those Coral, Adcom and Saes cartridges were on ebay/agon sites but I was and I'm not tempted to test one of those cartridgesm maybe we have to do it and see what Coral has to " shows " us.
Maybe some one of the Agoner's could put some " light " on that subject.
Regards and enjoy the music, R. |
Dear friends: Always is important to know and learn why and how " things " works ( as AS and any other audio subjects. ) to make concience of the importance of the set up on that " subject " regards.
Till this moment almost no one posted not what happen or not but what we heard when applying the AS in correct way or incorrect way, I think Timeltel mentioned about but there were no " quorum " to speaks on listening experiences. At the end and after the " learning time " the most important subject ( IMHO ) is or are each one of us experiences under playback.
Same happened with my last post to Fleib where I left a " question " in the air: how to match VTF/VTA with overhang tonearm cartridge geometry set up? because when we make a tiny change on SRA/VTA or VTF exist a change in overhang too and we have to reset this parameter that could change those VTA/SRA/VTF tiny changes. On this reset set up changes the stylus tip change its position and " reads " the grooves with tiny differences that maybe through playback could like us at random or not.
What are your take here or what do you think about? is there something wrong that I'm unaware? am I wrong? why?
Regards and enjoy the music, R. |
Hi Raul, Do you have experience with any Coral cartridges? Years ago I had an Adcom HOMC that I believe was made by them. The SAE 1000 is said to be there's also. I seem to remember something about a model 777? Thanks, |
Timetel/John_Gordon,
Thanks. Expertise is really useful and most welcome.
As always... |
Regards, John Gordon: Thanks for the reference. I thought your information useful and presented in a practical and easily read fashion. Input from professionals is always welcome.
Peace, |