Dover, You raise a question about which I have long wondered. We discuss the "grave" consequences of tracking angle error as if they are factual, which is to say verified by actual experiments. The claims for a correlation with distortion and phase anomalies make teleological sense, but do you know of any actual studies that have been done to correlate tracking angle error with those undesirable consequences? That goes back to my mentioning the need for an LP encoding a single frequency from start to finish, so one could observe the effects of TAE directly.
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Raul, I mentioned in my long post that although I do own the RS Labs tonearm, I don't use it much, for the other reasons cited. It is "tricky" to use, has no cueing device, and places the cartridge in jeopardy, because the unipivot bearing does not capture the arm wand in place. If you jostle the body of the tonearm, the whole arm wand is apt to fall off its pivot and could destroy the cartridge. The Ortofon MC7500 that I bought from you never sounded better than when mounted in the RS Labs, on the other hand. I just didn't have the guts to use it that way long term. Because I do like the sonics of the RS Labs, I was attracted to the Viv Float, a more sensible alternative. However, the Viv is very expensive, $6K-ish I think in the USA. You can buy one in Tokyo for more like $3500, but that is still not "cheap". I agonized over a purchase last time I was in Tokyo but did not pull the trigger. And the Viv has some other quirks that one would need to evaluate, like that oil bath bearing assembly. No, you are correct, underhung tonearms are not going to take over the world. But if someone would just make one that is less gimmicky than either the RS Labs or the Viv, I think it would sell if the seller would accurately describe its characteristics to buyers. The Yamaha tonearm, so far as I know, is only available together with their new turntable. Now we are far away from a discussion of headshells. Sorry to the OP.
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Yes, Raul, it is useless. You cannot use it to make a campfire or to deliver a baby or change a tire. All of this discussion is useless, on that level. I'm sorry if I offended you by my choice of subject. But can you see how all the blather about effective length, pivot to spindle distance, headshell offset angle, etc, etc, can be put to rest if you think about the mechanics of an underhung tonearm? There are many misconceptions surrounding that type of tonearm, and I thought it was relevant to describe here what they can and cannot do, for anyone who is interested. It is indeed a pity that there are not more underhung tonearms from which to choose. Like you say, it is indeed a free country, if not everywhere a free world.
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Just one comment about the much misunderstood underhung group of tonearms. There are only a very few of them that I know about: RS Labs RS-A1, Viv Float, and the Yamaha. Can anyone name others? These are all straight tonearms with no headshell offset, and they all underhang the spindle. As such, only one single null point is possible on the surface of the LP. The best way to set them up is to arrange to place the null point (cantilever parallel to grooves) somewhere at or near the middle of the distance from outermost groove to innermost groove. These tonearms exhibit a great deal of tracking angle error (TAE) at the outermost grooves, more than one would ever calculate for a conventional overhung pivoted tonearm. TAE will be inversely proportional to the pivot to stylus distance. TAE then diminishes linearly as the stylus tip approaches the single null point. Also the TAE results in a skating force that is similar to conventional skating force, with a net vector directed toward the spindle. That skating force also diminishes linearly with distance from the single null point. With this type of tonearm, at the single null point, skating force is also zero for that one instant. This is different from conventional tonearms, because in that case skating force is never zero; even at the null points, there is skating force due to headshell offset. Once the underhung tonearm has passed through its single null point, TAE begins to increase again in a linear fashion, as the stylus approaches the innermost groove. BUT the vector direction of the skating force that goes with it is in the opposite direction, pulling stylus tip outward. That is why you won’t find an anti-skate device on an underhung tonearm; it would be very difficult to imagine an anti-skate mechanism that would "know" when to change direction.
Like I said, these tonearms do exhibit a lot of TAE, but TAE does not wax and wane as it does with conventional pivoted tonearms, and there is a period around the null point where the skating force and TAE are very low to nil. The understanding of these tonearms is complicated by some of the foolish and patently false claims made by their makers. The RS Labs instructions say that there is no skating force with their tonearm, which is wrong, for one example. But on the other hand, they sound more free of artifacts that one associates with TAE and skating force than all but some of the best linear trackers, without the complexity associated with those types. I wish there were more underhung tonearms from which to choose. I occasionally use the RS Labs, but I shy away from it because of its other oddities and potential danger to cartridges. But the RS Labs occasionally can sound like a master tape in its very stable imaging and low audible distortion. This observation leads me to question the wisdom of offsetting the headshell in order to achieve two null points on the surface of the LP. This results in a skating force due to the offset angle and in TAE that varies up and down in magnitude across the surface of the LP. Perhaps the variations in TAE effected by headshell offset angle and overhang make any resulting distortions more audible than they would be if the changes were more linear, as with an underhung tonearm. After all, Baerwald and Lofgren published their math in the late 1930s or early 1940s. If they even listened to music, they were doing so with wide-groove mono shellacs playing at 78 rpm (I am guessing). They couldn't know what the future of the art form would be. Why do we have to cling to their old ideas?
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To cut through the other stuff, Lohanimal, the statement you quoted does not indicate that one MUST use an FR headshell with an FR tonearm. Is that what you meant to say? Your quote from the owners manual only would stipulate that IF one is using an FR headshell, THEN one should place the stylus tip 7mm behind the front edge of the headshell. This helpful hint does not prohibit the use of other headshells, so long as they properly fit the bayonet mount. If using some other brand, one would simply need an alignment gauge for setting overhang. And anyway, it would be at least as much of a pain in the ass to measure that 7mm as to use a proper alignment gauge, maybe worse.
As to accuracy, I think the best most of us can do is within 1mm net error (or +/-0.5mm, in other words), between setting P2S and overhang. If you get it that close, you've done well. Then there's the longitudinal angle of the cantilever with respect to the particular algorithm. That requires patience.
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Bukanona, I am still not quite sure I understand your point. Surely you would agree that Euclid, Pythagorus, and the rest have left us enough formulae to deal with any nuance of tonearm alignment. If you consult the original papers by Baerwald and/or Lofgren, I am sure you would see they relied upon the geometry we learned in high school, albeit maybe not every high school student could solve their problem. As to the LP with a 1 kHz test tone, are you saying that I can buy such a test LP or that I could have one made? I chose the frequency of 1 kHz merely as an example of a pure tone that would be a reasonable place to start to measure distortion induced by tracking angle error; it is not a matter of right or wrong. Cartridge specifications usually list stereo separation at 1 kHz and cartridge output is often measured at 1 kHz. In the event, one might want to make such measurements at 100 Hz, 1kHz, and 10 kHz, and any other frequency of interest in between, I suppose. It's a matter of how much time and energy you would want to put into it. It would also be good to interface a computer between the output of the cartridge and the distortion analyzer, so that one could obtain a plot of distortion vs time and translate that into distortion vs location on the surface of the test LP.
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bukanona, What do you want to measure, tracking angle error or the distortion that results? The former is completely predictable using geometry handed to us by the Greeks and their mathematical descendants. The latter is complex, because you would need a test LP that encoded a single test tone, e.g., 1 kHz, from outer to inner grooves. It would be useful to have such a test LP, but I don't think it exists.
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Karl, I heretofore was under the impression that the distance of 230 mm was the original recommended pivot to spindle distance for the FR 64S, which implies it is for Stevenson alignment. The distance of 231.5 mm was recommended to me by a well-known guru who shall remain nameless, and I assumed he was assuming I would use Baerwaldt alignment. Therefore I have gone through life since then in the belief that 231.5 mm was the choice for Baerwald and 230 mm was the choice for Stevenson. It certainly is the pivot to spindle distance originally recommended by Ikeda. Note there are two assumptions involved. Raul has corrected me on this thread and noted that the distance of 231.5 mm can be used for either alignment. And I think he is correct.
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Raul, Speaking for myself, I have written nothing at all about the alignment formulae. I merely was trying to clarify the definition of the terms "effective length" and "overhang", for the benefit of the OP. In your opinion, did I make an error? If so, I would be grateful to be corrected.
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And “effective length” is pivot to stylus; 231.5mm or 230mm is pivot to spindle for FR64S. The difference between the two is “overhang”.
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Thanks, Raul. I think you are correct, now that I recall what I have read in the past.
Chakster, In your parlance, does "NG" mean "No Good", which it would mean in colloquial English? I have the old original Feickert, made of white plastic with black markings, where the platform is the full size of an LP.
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230mm for Stevenson
231.5mm got Baerwald
I use Feickert protractor or old version of SMARTractor. SMART is absolutely the best IMO. Feickert is much easier and faster. Depends how anal I feel that day.
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I have used Ortofon LH9000 (for high effective mass, weighs 18g by itself) and Oyaide and Yamamoto carbon fiber headshells (both weigh ~10g; for high-ish compliance cartridges). In fact, I have never owned an FR headshell and wouldn't be looking for one, because they do not have the best reputation for sonics. With the P2S set at 231.5mm, as in your case, the headshell screws are about midway in the slots of all 3 of those headshells, when doing Baerwald alignment. So I don't know what your problem could be; it should work fine.
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