I understand the difference in value is very small for a cycle and a spiral. But even conceptually, it is the same saying perpendicular to the radius of the LP as saying tangent to the groove(spiral).
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Member
Joined 2019
I am still waiting some formula from my mathematician friend. By now, he noted that unlike the linear spiral, where the angle deviation from 90o decreases with the rise of the radius, in the logarithmic spiral this deviation is constant, again not being 0o.
So far, I use the cartesian equation of a linear LP grooves spiral with a step of 0.1 mm, in the groove radius of 100 mm.
(x^2 + y^2)^0.5 = 100 + 0.0159 atan(y/x) ……………… expressed in the Excel functions language
I look for the equality of the left and right parts of the above equation in x steps of 0.02 microns. I do the same for a circle with the same local parameters. My results indicate an spiral angle within 89.95 - 89.97 degrees = a difference from the verticality within 0.03 - 0.05 degrees.
So far, I use the cartesian equation of a linear LP grooves spiral with a step of 0.1 mm, in the groove radius of 100 mm.
(x^2 + y^2)^0.5 = 100 + 0.0159 atan(y/x) ……………… expressed in the Excel functions language
I look for the equality of the left and right parts of the above equation in x steps of 0.02 microns. I do the same for a circle with the same local parameters. My results indicate an spiral angle within 89.95 - 89.97 degrees = a difference from the verticality within 0.03 - 0.05 degrees.
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Member
Joined 2019
How many angels can dance on the head of a pin?
I guess it seems that way. I don't know about other people but I would prefer the thread to focus more on designs and implementations, you know the kind that befits a hobbyist forum... something fun. But splitting hair can be fun too... to a nuclear physicist!
I guess it seems that way. I don't know about other people but I would prefer the thread to focus more on designs and implementations, you know the kind that befits a hobbyist forum... something fun. But splitting hair can be fun too... to a nuclear physicist!
Member
Joined 2019
I don't know.
Since Consty created a graphic model on post#1985 so the geometry is there to reverse engineer. Perhaps you can figure out if skating force exist or not. But I agree with Niffy that since it pivots, it more than likely exhibits skating force.
Just by observation, the headshell has to move laterally in a straight line so the tonearm base has to move FORWARD from the middle point in order to maintain tangency. I wonder what the effective mass is and does it maintain consistently across the whole record?
PS, I can't open nor know how to use the app nor have the will power (aka lazy) to belabor on it. Perhaps next time someone can give the option of showing snap shots (JPEG) of the geometry and post it so the idea gets across - you know, the cliffnotes version of it?
Member
Joined 2019
I just realized the Klaudio uses a magnetic guide in the back end to move the arm base, with linear bearings, in order for the headshell to be tangent to the radius and it reminds me of the much discussed Schroeder LT tonearm, which also employs an ingenious magnetic guide in a pivot arm with a quasi-Birch geometry. It may not theoretically have zero skating but in my opinion is much simpler and more elegant in its solution than the Klaudio which has too many linkages for my liking. And it's easier for DIYers!
Member
Joined 2019
directdriver, I read, for the first time, a lot of pages of your thread and I feel the need to congratulate and thank you for all the interesting and important material you have found and exposed here!
As for Schroeder LT, I think that it is a very intelligent design. And I believe that people of this level of technical intelligence would never lie stating that there is no skating force in their turntable. Greetings!
long life to the offset
Now you will tear me in pieces but, after so many TAs (lately even a weird linear tracker) came up to me some naive doubts.
Why so much worrying about the "skating" of pivoted TAs, and not to the Side Force of the linear ones?
It seems to me the same kind of force, only applied on different sides (inner vs outer) of the groove; both generate bending, which is worse (generator misalignment) than a similar tracking error angle (thanks to the rounded tip)
Certainly the skating (variable) is only partially compensable, but the side force not at all (we can only try to reduce frictions and levers) and variable too, on eccentricities. Then, inter nos, given the kind of levers (unfavorable vs. favorable) and cable positioning, the side force of a linear can often be more relevant than skating.
It's there a way to move a tonearm without a side force? or at least without generating bending?
What if the damn offset produced only a quantity of side force equal to the friction of the pivot? (or vice versa if the friction of the pivot changed according to the stylus drag variations?)
For sure, to get a stylus tip sitting comfortably right in the middle of the groove at least we have almost to halve the offset (on a good pivoted - from some rough calcs and measures), but above all it would need a magical (passive of course) "servobrake" for the stylus drag variation (20-30% - on my old pendulum test).
Such as? do not ask me, it comes to mind only something like the self-regulating mechanism of steam engines, nothing to deal with. Pivoted TA await their Mr. Watt
carlo
forgive the ignorance of a diyer's, focused on effects more than on causes.
Now you will tear me in pieces but, after so many TAs (lately even a weird linear tracker) came up to me some naive doubts.
Why so much worrying about the "skating" of pivoted TAs, and not to the Side Force of the linear ones?
It seems to me the same kind of force, only applied on different sides (inner vs outer) of the groove; both generate bending, which is worse (generator misalignment) than a similar tracking error angle (thanks to the rounded tip)
Certainly the skating (variable) is only partially compensable, but the side force not at all (we can only try to reduce frictions and levers) and variable too, on eccentricities. Then, inter nos, given the kind of levers (unfavorable vs. favorable) and cable positioning, the side force of a linear can often be more relevant than skating.
It's there a way to move a tonearm without a side force? or at least without generating bending?
What if the damn offset produced only a quantity of side force equal to the friction of the pivot? (or vice versa if the friction of the pivot changed according to the stylus drag variations?)
For sure, to get a stylus tip sitting comfortably right in the middle of the groove at least we have almost to halve the offset (on a good pivoted - from some rough calcs and measures), but above all it would need a magical (passive of course) "servobrake" for the stylus drag variation (20-30% - on my old pendulum test).
Such as? do not ask me, it comes to mind only something like the self-regulating mechanism of steam engines, nothing to deal with. Pivoted TA await their Mr. Watt
carlo
forgive the ignorance of a diyer's, focused on effects more than on causes.
Hi Carlo,
My calculations and measurements would indicate that the side forces acting on my linear tracking arm with a concentric record are a lot less than those that you would get due to the errors in a well set up anti skate mechanism on a 9" arm.
With a record with a 0.5mm eccentricity, which would result in the cartridge body moving side to side by 1mm, will add inertia to the bearing friction and bring the total error up be similar to the total errors of the 9" arm.
As most records have less than 0.5mm eccentricity my arm will have less error due to friction and inertia combined than the 9" arm due purely to the variation in skating force. And this is assuming that the antiskate is perfectly set for minimum average error. Don't forget the gross error due to geometry of the 9"arm isn't included in this comparison.
Different types of linear arm will have different amount of bearing friction and mass so will produce different errors.
Niffy
My calculations and measurements would indicate that the side forces acting on my linear tracking arm with a concentric record are a lot less than those that you would get due to the errors in a well set up anti skate mechanism on a 9" arm.
With a record with a 0.5mm eccentricity, which would result in the cartridge body moving side to side by 1mm, will add inertia to the bearing friction and bring the total error up be similar to the total errors of the 9" arm.
As most records have less than 0.5mm eccentricity my arm will have less error due to friction and inertia combined than the 9" arm due purely to the variation in skating force. And this is assuming that the antiskate is perfectly set for minimum average error. Don't forget the gross error due to geometry of the 9"arm isn't included in this comparison.
Different types of linear arm will have different amount of bearing friction and mass so will produce different errors.
Niffy
Depending on the passage of the bible you read and how you interpret it all angels are either male or sexless. There are no female angels. Hollywood has a different story to tell. Of course the important question is can you remove them with a stylus brush.
Niffy
Angel's gender:
I hoped that, after the useless efforts of theologians, science could tell us something conclusive about a topic of such vital importance. Their unexpected presence on the stylus clarifies many mysterious aspects, but it is not as much a quantitative problem (you can always put fat angels - for sale on bangood - on the CW,) but just of sound. Since two centuries the drastic solution recommended by our Roman church for angelic choirs is no longer practiced (but how to replace a Farinelli?) so what countermeasures can be used?*
Offset:
I know well (and envy) your splendid tonearms, but the reality of the common LT is worse, and skipping is often behind the corner.
So I was wondering: since the bigger defect of the offset is to produce too much and variable side force, what can we do to produce less? better, exactly what's needed? Considering too that the offset seems the only way to get it from both sides of the groove, i.e. without cantilever bending.
But really I have no idea of how to, and to start with an 18" arm seems a nightmare.
That's fun - carlo
*no female angels? dangerous statement nowadays, Niffy....
I hoped that, after the useless efforts of theologians, science could tell us something conclusive about a topic of such vital importance. Their unexpected presence on the stylus clarifies many mysterious aspects, but it is not as much a quantitative problem (you can always put fat angels - for sale on bangood - on the CW,) but just of sound. Since two centuries the drastic solution recommended by our Roman church for angelic choirs is no longer practiced (but how to replace a Farinelli?) so what countermeasures can be used?*
Offset:
I know well (and envy) your splendid tonearms, but the reality of the common LT is worse, and skipping is often behind the corner.
So I was wondering: since the bigger defect of the offset is to produce too much and variable side force, what can we do to produce less? better, exactly what's needed? Considering too that the offset seems the only way to get it from both sides of the groove, i.e. without cantilever bending.
But really I have no idea of how to, and to start with an 18" arm seems a nightmare.
That's fun - carlo
*no female angels? dangerous statement nowadays, Niffy....
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"*no female angels? dangerous statement nowadays, Niffy...." just pointing out the male orientation of dogma.
The klaudio design probably has the lowest offset of any pivoted arm. Ranging from about -7° via 0° to +7° across the playing area of the record. This will result in an average of only a couple of degrees, much lower than the 20+° of most arms. This will massively reduce skating force and the requirements of a bias mechanism. It could explain why I can't see an anti-skate mechanism on this arm. The resulting skating force is too small to be worried about compared to the complexity of the required bias mechanism.
When working with skating (or whatever you wish to call it) I have found that it much easier to consider it as a torque about the main pivot. Any biasing mechanism needs to produce an equal torque in the opposite direction. The actual force applied at the stylus is a much more difficult starting point to design from.
Niffy
The klaudio design probably has the lowest offset of any pivoted arm. Ranging from about -7° via 0° to +7° across the playing area of the record. This will result in an average of only a couple of degrees, much lower than the 20+° of most arms. This will massively reduce skating force and the requirements of a bias mechanism. It could explain why I can't see an anti-skate mechanism on this arm. The resulting skating force is too small to be worried about compared to the complexity of the required bias mechanism.
When working with skating (or whatever you wish to call it) I have found that it much easier to consider it as a torque about the main pivot. Any biasing mechanism needs to produce an equal torque in the opposite direction. The actual force applied at the stylus is a much more difficult starting point to design from.
Niffy
Member
Joined 2019
If we take an average Klaudio offset of 3.5°, than the lateral component of the friction force will be roughly 7 times lower than in the case of the classical offset of about 23°. For the extreme Klaudio 7°, the decrease will be about 3.5 times. Quite better, but still not perfect. I do not thing that compensating the Klaudio skating force would be be a serious problem for these high-level constructors. So, I still remain wondering.
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Thank you!
Thank you for the kind words. I'm just an armchair philosopher and just stir the pot here. My motto is to take life seriously enough but not to take myself too seriously. If this thread provided some entertainment, then I'm happy for the readers.
With the contributions from people like Mark Kelly, Niffy, super10018/Jim, Straight Tracker/Ralf, Berlinta/Frank, diyrayk/Ray, and numerous others, they help tweaking and correcting ideas here and more importantly keeping me and others honest. Special thanks to nocdplz/Carlo and Dtut/Doug Tuthill for actually building real diy tonearms from ideas in here that elevated the credibility of this thread. You guys embody the true experimental spirit of DIYers and are the real trailblazers! Thank you!
Thank you for the kind words. I'm just an armchair philosopher and just stir the pot here. My motto is to take life seriously enough but not to take myself too seriously. If this thread provided some entertainment, then I'm happy for the readers.
With the contributions from people like Mark Kelly, Niffy, super10018/Jim, Straight Tracker/Ralf, Berlinta/Frank, diyrayk/Ray, and numerous others, they help tweaking and correcting ideas here and more importantly keeping me and others honest. Special thanks to nocdplz/Carlo and Dtut/Doug Tuthill for actually building real diy tonearms from ideas in here that elevated the credibility of this thread. You guys embody the true experimental spirit of DIYers and are the real trailblazers! Thank you!
A more important question is can we convince them to congregate on the backside of the stylus and push the dust and debris out of the way for us in order to reduce ticks and pops. This may be a bigger factor than worrying about stylus contact profiles.
Ray K