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VTA method???

Thomas_AA said:
You seem not to grasp the problem. Shims are of course angled. Tonearm height changes the force vectors of the arm. Just follow my previous links.

www.wallyanalog.com

Corrective Shim - Cured Resin | WallyTools

+3 to -10 degree corrective shims available. Angular correction on the front back (SRA/VTA) axis only. Price includes top side shims (standard and Kuzma style). A negative number is in same direction as if you were to LOWER the arm height.
www.wallyanalog.com www.wallyanalog.com
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Angled shims? Good luck! I am sure you are Smolandian! Or a Scotsman who lives in Sweden! ;)
 
Thomas_AA said:
Classic! You like to discuss persons rather than the topic at hand. No arguments from you left I think.
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The argument is obvious. Instead of replacing a defective cartridge, you try to make strange constructions. Ebenezer Scrooge is not your relative?
 
For those others interested in what a 7° change in SRA/VTA did to frequency response: Nothing.

www.audiosciencereview.com

Fun with vinyl measurements

the purpose remains the music if it is not heard what is the point? ;-) (on very demanding music and trained and demanding listeners for example... for many factual reasons, the piano often comes back ;-))
www.audiosciencereview.com www.audiosciencereview.com
 
Thomas_AA said:
How many cartridges have you tested meeting the 18°-20° VTA standard?
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Are you live in Småland jungle where only defective cartridges are available? I have aligned many cartridges within 40 years, mostly Ortofon MC (Made in Denmark. You should know, it is civilized country near Småland) and they all was up to specs. But I doubt you heard something about test records.
 
radiokom said:
Are you live in Småland jungle where only defective cartridges are available? I have aligned many cartridges within 40 years, mostly Ortofon MC (Made in Denmark. You should know, it is civilized country near Småland) and they all was up to specs. But I doubt you heard something about test records.
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Fine, so show me some measurements then, especially those with replicant stylii. Should be easy to extract distortion and plot VTA from those STR160 or DIN records with varying VTA cuts.
 
Thomas_AA said:
Fine, so show me some measurements then, especially those with replicant stylii. Should be easy to extract distortion and plot VTA from those STR160 or DIN records with varying VTA cuts.
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I'm sorry, but I don't want to prove anything to you. Many have tried to enlighten you in this thread before me, but it is hopeless and pointless.

 
Last edited:
lini said:
That's not a question of the brand, but rather a question of the specific models. For example, the classic SME 3009 family models don't sport that correspondingly angled vertical pivot axis, while the SME series V does. And for example all Technics SL-12x0Mky tonearms also do - and many more.



I'll give you two simplified examples, combined in a quick & dirty drawing (*), that I just made with MS Paint:

View attachment 3382207

In both cases I use a simple, hook-shaped, straight tonearm arrangement (in black), which makes things easier, 'cause in this case the actual and the virtual tonearm axis are the same (as are the headshell and the offset angle), and the length of the long part of the hook hence simply equals the effective length.

Well, and each red line (plus short part of the hook) would now show, what I call the effective nodding axis - on the right side in case of the correspondingly angled vertical pivot axis, on the left side in case of the vertical pivot axis being perpendicular to the arm tube instead. And each yellow line simple prolongs the vertical pivot axis to the rear end of the effective nodding axis, which one could also call the effective nodding pivot point.

So now it should be pretty easy to see, that on the right side the length of effective nodding axis = effective length * cos (offset angle), whereas on the left side the length of the effective nodding axis = effective length / cos (offset angle).

Well, and provided, that the initial tonearm orientation is horizontal and that one doesn't readjust for the slightly altered effective length after pivot height change, I'd calculate the change in SRA with arcsin (height change / length of effective nodding axis).

Greetings from Munich!

Manfred / lini


*) So never mind, that the angle of the red line on the left side isn't quite correct.
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A little late to respond...Correct me if I'm wrong but your diagrams above are along the horizontal plane. I was looking at the vertical plane and I think it is pretty straight forward trigonometry to calculate the change in SRA. I don't want to get into the semantics of a tonearm's effective length but I don't think what you have called the nodding axis applies to find the change in SRA because of a vertical change of the tonearm's vertical pivot.

I simplified the calculations in my earlier post and used the effective length (a horizontal measurement as I understand it) when I should have held the actual length between the center of the vertical pivot where the arm wand enters the vertical bearing (either of the types you've shown above) and where the stylus contacts the record. I think this diagram will clarify what I'm saying.

SRA-1.png

For this exercise lets say:
  • The distance between the center of the vertical pivot and the stylus measured horizontally is 250mm
  • The Height of the Cartridge is 17mm
  • 1mm will be the increase in the height of the vertical pivot point above an initially level tonearm
  • "A" is a constant and is the distance from the tip of the stylus to the center of the vertical bearing
"A" = SQRT(17^2+250^2) = 250.57mm

Alpha = arcsin 17/250.57 = 3.8901°
Beta = arcsin 18/250.57 = 4.1193°
Delta = 4.1193° - 3.8901° = 0.2292° or 0.23° = The change in SRA due to a 1mm change in the height of the vertical pivot.

For all practical purposes this is the same as my earlier calculations.

Another thing to note is the stylus moves towards the tonearm base as seen in the diagram with a change in the height of the vertical pivot. For the example above that change is 0.08mm and a 4mm change in the vertical pivot would be 0.32mm. IMO it will be difficult at best to differentiate 0.32mm using the typical printed arc protractor but changes in the height of the vertical pivot greater than 6mm to 8mm may require redoing the cartridge's alignment.
 
AvFan said:
A little late to respond...
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No problem.

AvFan said:
Correct me if I'm wrong but your diagrams above are along the horizontal plane.
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Well, one could view 'em that way, too - but that doesn't really matter for the principle (or respectively for what I intended to illustrate).

AvFan said:
I simplified the calculations in my earlier post and used the effective length (a horizontal measurement as I understand it) when I should have held the actual length between the center of the vertical pivot where the arm wand enters the vertical bearing (either of the types you've shown above) and where the stylus contacts the record. I think this diagram will clarify what I'm saying.
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No worries, I didn't have a problem with the slightly simplified calculation.

The actual problem of your calculation is, that it would only work out for a linear-tracking arm (or a completely straight (= no offset angle) radial-tracking arm with a single null point at (or, allowing for a reasonably small error margin, very near to) that null point). Whereas otherwise your calculation won't work out correctly, because you're calculating the change of inclination along the virtual tonearm axis (between the needle tip and the actual pivot point), which in case of a typical radial-tracking arm is not the same as the SRA, though, as the SRA refers to the inclination along the groove tangent - that being the actual point of my objection and what my drawings are supposed to illustrate.

Or in other words, referring to my drawing: What you're calculating, is the change of inclination along the long side of the hook - rather than the change of inclination along the short side of the hook. See?

Greetings from Munich!

Manfred / lini
 
lini said:
SRA refers to the inclination along the groove tangent
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Good discussion and it is thought provoking. I sort of see your point, but I don't think there is any difference on SRA when changing the arm pivot height by accounting for the offset angle. The SRA should stay the same across the entire record because the pivot height, record surface height and effective length are fixed. Yes, I guess you could call the effective length a virtual tonearm axis but that is the plane I'm using; I'm not concerned about the zenith of the stylus to the groove since it is only correct at the two null points. If I understand your point, wouldn't the SRA vary across the record and should be set at the null points? Maybe you can show me how to calculate the SRA based upon how you understand SRA is determined.

0515TAB.jpg
 
AvFan said:
(...) If I understand your point, wouldn't the SRA vary across the record and should be set at the null points? (...)
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Yes, it would, but only very minmally so, as the remaining tracking error angle over playback radius doesn't add/subtract much to/from the offset angle (typically less than 10 % max.) - and hence I also wouldn't suggest to set it at one of the null points, as one wouldn't be able to spot the difference anyway.

Greetings from Munich!

Manfred / lini
 
SRA would matter at high frequencies and if the contact patch of a line contact is sufficiently long. This would in turn be dependent on the deformation depth of vinyl and stylus pressure. As the diamond wears the large radius gets larger and is a ”line” at the end of its life. So SRA becomes more important as it wears.
 
lini said:
Yes, it would, but only very minmally so, as the remaining tracking error angle over playback radius doesn't add/subtract much to/from the offset angle (typically less than 10 % max.) - and hence I also wouldn't suggest to set it at one of the null points, as one wouldn't be able to spot the difference anyway.

Greetings from Munich!

Manfred / lini
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I think you are going to have to show me the calculations to support that SRA changes across the record. I don't see how that can be true when there is only one variable and that is the arc of the stylus. The pivot heights, record surface height and effective length are fixed values and IMO define the SRA. I don't think the bearing type/angle, as you showed in your earlier diagrams, matters when determining SRA. Show me why that is wrong.
 
AvFan said:
(...) I don't think the bearing type/angle, as you showed in your earlier diagrams, matters when determining SRA. Show me why that is wrong.
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It's wrong, because it would disregard the included error of perspective.

Simple example: Imagine you'd only have one eye and you'd walk up to a pole, that's not exactly upright/perpedicular relative to the ground, from a good bit away, so that you can't see it in detail yet. Now the two most extreme errors of perspective would be, if you'd happen to approach the pole exactly in line with its plane of inclination, so that it would actually lean either towards or away from you, while to you it would appear upright instead. So now you don't directly walk up to that pole anymore, but instead beging to walk around it in a circle - then the error of perspective will reduce more and more, until it reaches zero at the two spots on the circle, at which your view is perpedicular to the plane of the inclination of that pole, so you can now see its actual inclination relative to the ground.

The same goes for the SRA: For calculating the actual inclination along the groove tangent the perspective of that calculation needs to be perpendicular to the groove tangent, not perpendicular to the virtual arm axis - 'cause in the latter case the calculation would also contain an error of perspective, so that the result wouldn't quite equal the actual SRA (= inclination along the groove tangent). And hence, now referring back to my drawing and calculation formulas in post #80, the need for the two case-dependent correction factors:

One the left: change in SRA = arcsin (height change / (effective length / cos (offest angle)))

And on the right: change in SRA = arcsin (height change / (effective length * cos (offset angle)))

Well, and as already hinted to, the angle between the virtual tonearm axis and the groove tangent can be expressed as the offset angle +/- the remaining tracking error angle - with the latter being zero at the two null points, positive before the first and after the second null point and negative between the two null points. But due to the remaining tacking error angle being quite small compared to the offset angle, disregarding it doesn't introduce much of an error of perspective. So I'd suggest to forget about the slight variation of the SRA over playback radius - that's simply too small to be of any actual relevance.

Greetings from Munich!

Manfred / lini
 
Just want to note that I made a write-up of my test on SHF here:

forums.stevehoffman.tv

An SRA/VTA experiment

I made an SRA/VTA experiment with my Shure V15Vx and JICO SAS/B stylus. It is known that the VTA of these stylii are quite steep, around 30° effective...
forums.stevehoffman.tv forums.stevehoffman.tv

So far it has not stirred up much which is a bit surprising giving the many proponents of tail up and tail down "equaliser".
 
Fishead said:
Funny, notice how the OP, @rodman101 has not been heard from since post #1? Sorry if we got a little carried away amigo, but there are a few subjects that will seemingly generate a lot of comments and this, I'm afraid, is one of those. Hope you have been following along, and besides, you did ask for comments!!! Good bunch here, just sayin'.....
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Definitely not carried away, I'm just taking it all in post by post, GREATLY appreciating all comments! For the most part none of this is new to me only the method of VTA adjustment method that started this thread. I'm still not sold that this is an advised method but from what I gather it can perhaps work for some cartridges, just by chance, and it obviously did for this one. My personal method is to fine tune VTA during play back using a recording that I know well and once in the sweetest spot possible lock it up. This can be a huge pain but has always worked flawlessly for me.
 
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