Sliding force???

I accidentally happened upon an ECM LP with a blank fourth side ("Into The Silence")

1547148458222.png

and notice what happens:


Then I enabled and adjusted anti-skating to tame it:


I know ddk has designed his platter to provide a sliding effect to some degree, but I thought mine was excessive. Still trying to assess possible sonic effect.
 
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jadis

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Tracking is wheels on rods like a model railroad engine, bearing of tonearm is some kind of gimbal.

There are 5 or 6 optical sensors, one of which in retrospect I may have activated by handling a flashlight while cueing up. One must read the manual or it can act like it has a mind of it's own. I guess it does in a way.

Tech info:
https://www.vinylengine.com/library/pioneer/pl-l1000.shtml

Just the tonearm on fleabay.

https://www.ebay.com/i/352835080771...81KH0zlvs6KEF4gfKj7wiCzh9yCtjrpIaAl9wEALw_wcB
View attachment 64980 View attachment 64981
Btw, does your tonearm have that very slight sloping down movement toward the spindle area?
 

kach22i

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Btw, does your tonearm have that very slight sloping down movement toward the spindle area?
No.

And it is NOT in the air bearing family of tonearms to be clear.

Not a monorail hovercraft, it is a railroad engine on tracks.

The Pioneer/Phase Linear 8000 is more like a grandfather to the Dereneville and contemporary cousin to the Yamaha PX-3 and Sony PS-X800.

EDIT:

I don't know much about the Souther. However I found this on the topic.

Quote:
3. Leveling- forget that "set for slight downward-angle" (toward spindle) crap. Level the sucker. Downward angle is only relevant when considering that perfect level is not possible; error (read tiny error) should be downward toward the spindle.

End Quote.

From here:
https://forums.stevehoffman.tv/threads/souther-linear-arm-setup-tips-here.21195/

I will assume the slight non digital readout of a bubble level rule above applies to all linear tonearms. Just a guess or assumption. Again maybe too much has been made of this nuance.
 
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jadis

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No.

And it is NOT in the air bearing family of tonearms to be clear.

Not a monorail hovercraft, it is a railroad engine on tracks.

The Pioneer/Phase Linear 8000 is more like a grandfather to the Dereneville and contemporary cousin to the Yamaha PX-3 and Sony PS-X800.

EDIT:

I don't know much about the Souther. However I found this on the topic.

Quote:
3. Leveling- forget that "set for slight downward-angle" (toward spindle) crap. Level the sucker. Downward angle is only relevant when considering that perfect level is not possible; error (read tiny error) should be downward toward the spindle.

End Quote.

From here:
https://forums.stevehoffman.tv/threads/souther-linear-arm-setup-tips-here.21195/

I will assume the slight non digital readout of a bubble level rule above applies to all linear tonearms. Just a guess or assumption. Again maybe too much has been made of this nuance.
Thanks for the infos.
 

ack

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So I did a little experiment over the weekend... Removed the anti-skate setting (really easy to do on this VPI arm), and using the blank LP, I wanted to understand at what VTF would the arm remain stationary, with this cartridge; below 1.7g, it started moving backwards; at roughly 1.7g it was stationary, and above that, it started sliding forward. So this says - as VPI claim - that there is already built-in anti-skate by virtue of the arm wires sticking out and connected to the junction box. Moreover, if I ever were to have a cartridge that requires 1.7g or less VTF, it'd better be a heavy one, or I'd have to add additional mass to the arm. In fact, exactly because the A90 being so light is why I have already added additional mass to the arm in the form of copper shields around the wand.

So again, I would say that a pivot arm w/o anti-skate is not a good thing, and yet again, natural glide (not excessive) is also a good thing. Both are apparently dependent on the offset angle, the total arm/cart mass, and the tracking force. So the additional anti-skate I now use was chosen to be 100% of the difference between final VTF (2.3g) and at-rest VTF (1.7g) - i.e. roughly 0.6g worth of weight for THIS arm and cartridge - based on listening sessions. It sounds really good, and I can tell that above and below that, distortion rises.

Voodoo? Sure; I claim no mathematical proof here.
 

PeterA

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That is interesting Tasos. I still don't know how anything can be judged from a blank LP because it is the friction of the stylus in an offset headshell on a pivoting arm against the grooves that creates the skating force. I think in general, less is more, at least with my 12" arms and stylus profiles. I also tend to follow the recommendations of the manufacturer which for my vdHs is around 0.2-0.4 g. That is the starting point, and then I play with small adjustments and listen for best sonics.

I read an interesting observation. Too little bias, the cello section starts to distort. Too much bias, the violin section starts to distort. It probably depends on location on the LP and the range is probably wider than one would think. It might depend on the arm as well, gimbal v. unipivot.
 
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ack

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That is interesting Tasos. I still don't know how anything can be judged from a blank LP because it is the friction of the stylus in an offset headshell on a pivoting arm against the grooves that creates the skating force.
So keep in mind, I still make a distinction - as discussed upthread - between two different forces: one, which I called sliding, does NOT factor in the grooves, and is the result of geometry and VTF; the other, which has been universally and commonly described as skating, factors in the grooves, and especially the outer groove which pushes the stylus towards the center spindle.

I feel the first, sliding, force has to result, in my mind, into "natural" gliding of the assembly, as I said the other day. This natural slide allegedly does not stress the stylus, and then the stylus is freer to follow the path that the grooves dictate, without having to "carry" the arm along with it. That's, at least, my claim. The blank disc enables one to get a feel of this natural gliding motion.
 
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PeterA

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Tasos, if it is the outer groove which pushes the stylus towards the center, why would anyone want an opposite force acting upon the arm pushing the arm out toward the outer groove thus increasing even more the pressure/force/friction on the same outside face of the stylus? This implies too much force on the outer wall of the groove and too little on the inner wall of the groove.

I thought with insufficient anti-skate force one hears distortion from lack of contact with the outer groove, so you have to increase anti-skate to force the stylus more in the center of the groove so that it makes more or less equal contact with both sides.

If I hear distortion in the left channel, I lower anti skate. If I hear distortion in the right channel, I increase anti-skate. So if violins are distorted, you decrease it. If cellos are distorted you increase it.
 

ack

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Tasos, if it is the outer groove which pushes the stylus towards the center, why would anyone want an opposite force acting upon the arm pushing the arm out toward the outer groove thus increasing even more the pressure/force/friction on the same outside face of the stylus?
You simply want that force in order to control excessive gliding force, which itself pulls the stylus towards the center. That way, you end up with BALANCED forces, and the reduced gliding force kinda equals the push of the outer groove's: not too much pulling, not too much pushing. So this is why I think we need it; in other words, it's not adding to the push of the outer groove, it tempers the pull of the assembly. Think of it this way: I allege that, without anti-skate, it's an excessive gliding force that can cause distortions, in some arms - too much pull.
 
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PeterA

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Here is a Q/A with Mr. van den Hul about anti-skate and how to adjust it. BTW, he says that the modern stylii shapes produce less friction and therefore need less anti-skating force to compensate:

9 Q: How do I adjust the anti-skating force ?

A: The anti-skating force is necessary when you use a regular tone arm. So those few and proud owners of a linear tracker can read but don’t need to be bothered. The static anti-skating force is a minor force that pulls the arm to the outer rim of the groove during playing. This to compensate for the moment of force caused by the friction of the stylus in the groove (the force) and the moment arm (the distance between the tip and the vertical bearing). So, many arms have a little device close to the vertical bearing at their rear to compensate for this moment of force. As you will remember from your great physics lessons, two moments of force compensate each other when their direction is opposite. So playing causes a moment of force in clockwise direction and the compensating correction is automatically counterclockwise. It was a wise decision by the way to compensate. But as usual there are always new problems created when you try to solve old ones. One is the fact that music never has the same loudness, or stated otherwise, a record never has a constant amplitude or frequency. So a static compensation (the anti-skating force) has to deal with a dynamic problem. It doesn’t work well but it works better than no action. It depends on the difference in friction between the tip in a blank groove and the modulated tip how much you have to compensate. Round, spherical tips have much more friction in the groove (they really don’t fit well there) compared to special shapes like our VDH type 1 or VDH type 2. So it depends on the shape of the contact area between the stylus and the groove how much you have to compensate. The higher the frequencies cut in the record groove, also the higher the friction. For conical shapes (somewhat old-fashioned today and only mounted in cheap systems) the anti-skating force setting should be equal to the tracking force. With more groove-shape adapted stylus designs the anti-skating setting can be less. When a cartridge uses the VDH type 1 or VDH type 2 stylus, the anti-skating can be adjusted at 1/3 of the tracking force. This assuming that the scale on the tone arm is correct. Otherwise you have to listen to the sonic results. When the anti-skating setting is too high, the violins in the left channel on a record with classical music will distort during loud modulations. This is caused by missing contact between the stylus and the left groove wall. And when the antiskating setting is too low, the violoncellos will distort due to the missing contact between the stylus and the right groove wall.
 
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ack

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Thanks. I like the fact that: 1) vdH agrees there should be anti-skate applied, in most cases; 2) he tells us what to listen for; 3) offers some rough calculations for anti-skate based on stylus shape. Do not like that he doesn't discuss a) offset angle; b) arm/cartridge mass and intertia.

I do take at face value that what he says works well for his cartridges.
 
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PeterA

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Thanks. I like the fact that: 1) vdH agrees there should be anti-skate applied, in most cases; 2) he tells us what to listen for; 3) offers some rough calculations for anti-skate based on stylus shape. Do not like: a) that he doesn't discuss offset angle; b) arm/cartridge mass and intertia.

I do take at face value that what he says works well for his cartridges.
Ack, he does also discuss those issues, but the paper is extremely long and goes into many analog topics. Here is a link: http://www.goodsoundclub.com/pdf/Phono_FAQ.pdf

Happy reading.
 

tima

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Funny I had just gone through the van den Hul paper, when I see it referenced here. Since it is relevant to the discussion here (though its points are made in this thread) I'll add Q.13 to go with Peter's citation:

13 Q: Are there records that I can use for the adjustment of tracking force and anti-skating ?

A: A long time ago, when records were all around, there were also a lot of test records. In the meantime they have
disappeared to the barn. So look around to find one on your flea market. Some companies have lately produced records for this purpose. But any good record like older Deccas and EMIs will help you. Just listen and fine-tune both settings NEVER use an unmodulated record surface to adjust the anti-skating: This is static replay without the normal friction between the groove and the stylus, so don’t use this way of setup. The result is always a too low value and your violoncellos will distort again. Keep in mind that a too high anti-skating force will give asymmetrical tip wear on the outer part of the stylus. I.e. the lifespan of the stylus is shortened by a too high anti-skating setting.

(my bold)
 

jadis

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While I understand the 'gravitational' dead weight of the VPI Anti Skate device, I still can't grasp how it translate to a gravitational weight of 2 grams, for example. Can it be the same 2 grams of sideward thrust compared to the 2 grams of the VTF counterweight which is a downward gravitational pull as opposed to lateral pull? And what if you want to lessen the AS value, you just hook the thread into the next incantation of the VPI AS mechanism, how much 'grams' are we now talking about? And I am as baffled at the 2.0 AS dial setting of most pivot arms (dating back to the 70s 'cheaper' tonearms of those days). Is there a lateral weight that is present as the vertical weight which is measured in grams as we adjust the dial? And I am guessing that those round dials differ from brand to brand as far as the lateral force is concerned. Which now leads me to believe that we now measure the need for AS force by ear, re the cello and violin distortions.
 

tima

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And I am as baffled at the 2.0 AS dial setting of most pivot arms (dating back to the 70s 'cheaper' tonearms of those days). Is there a lateral weight that is present as the vertical weight which is measured in grams as we adjust the dial? And I am guessing that those round dials differ from brand to brand as far as the lateral force is concerned. Which now leads me to believe that we now measure the need for AS force by ear, re the cello and violin distortions.
I owned a couple of SME Vs, one with the removable headshell - both had the same dial as posted in Peter's photo earlier. Rather than a weight, a spring is used to apply the anti-skate force. Iirc the force of the spring correlates with the arm position on the record. I had no way to measure the applied a-s force, but the dial was effective in changing it. A well made arm.

I'm inclined to agree with you that the need for anti-skate is reactive. If we hear distortion, then consider applying anti-skate. I have a specific record I use to test for it. The album is Trio (Warner Brothers W1-25491) featuring Dolly Parton, Linda Ronstadt, and Emmylou Harris. Iirc the song I use is "Telling Me Lies"; it's the last on Side A and features Emmylou who has a very powerful dynamic soprano voice. If I hear a buzzing, crackling noise in the right channel I adjust anti-skate. It's a test I do as part of standard setup whenever I mount a different cartridge.

R-3290046-1400208864-9648.jpeg.jpg
 
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ack

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While I understand the 'gravitational' dead weight of the VPI Anti Skate device, I still can't grasp how it translate to a gravitational weight of 2 grams, for example. Can it be the same 2 grams of sideward thrust compared to the 2 grams of the VTF counterweight which is a downward gravitational pull as opposed to lateral pull? And what if you want to lessen the AS value, you just hook the thread into the next incantation of the VPI AS mechanism, how much 'grams' are we now talking about? And I am as baffled at the 2.0 AS dial setting of most pivot arms (dating back to the 70s 'cheaper' tonearms of those days). Is there a lateral weight that is present as the vertical weight which is measured in grams as we adjust the dial? And I am guessing that those round dials differ from brand to brand as far as the lateral force is concerned. Which now leads me to believe that we now measure the need for AS force by ear, re the cello and violin distortions.
Phil, let me see if I can address these questions in a simple way, and please bear with me...

1) Regarding the "how much anti-skate force do I exert": on the VPI arm, and because the anti-skate device is rotational as shown below, it will require some math. Below is the anti-skate at the lead-in and lead-out grooves, and as you can tell, it will vary slightly, with less force applied at the lead-out grooves because of the angle of the anti-skate lever:

IMG_4064.jpg

IMG_4069.jpg

Those rubber weights are 0.116g each, and five of those give me (as I said yesterday) roughly 0.6g that I wanted to apply. However, because this is a lever device, the actual force exerted mathematically depends on the offset of those weights away from the pivot point (that screw) - the further away, the more the force. In my case, since I have five, the distance is averaged out and is calculated based on the 3rd disc. In addition, the other arm has significant mass of its own, which would further reduce the anti-skate force, when it rotates

I did some measurements and rough calculations, and the maximum force (in the lead-in grooves) would be roughly 28% the VTF of 2.3, or 0.65g, very close to the ratio vdH recommends.

Now, regarding the varying force as the arm moves and anti-skate rotates... one might be tempted to say that this device, as is, is flawed; however, there is at least one more parameter here, and that is the wires coming out of the arm as shown below, which as I mentioned yesterday, I can demonstrate with the blank disc that they have an anti-skate effect of their own, at various places along the tracing arc. What actually happens is that those wires ADD additional anti-skate force towards the center of the disc, and therefore, the rotational anti-skate device's reduced force compensates for that. Again, the blank disc has been very valuable in figuring out all kinds of things about mechanical behavior.

All in all, the end result is closer to a linear *total* anti-skating force across the tracing arc than I had originally thought. This being vinyl analog, EVERYTHING is an approximation, and here we are.

IMG_4070.jpg

2) Regarding the question about where to put that anti-skate thread: I use the position which results in the least rotational travel, for minimal variability in the force

3) Regarding the question, well, how do I know how much actual force am I applying with any arm, or those arms with a dial: I don't think you can, at least not easily. In my case again, I *think* I have fairly correctly calculated it, but I am not sure it's entirely accurate

4) Regarding your guess that those rotational dials differ from arm to arm: yes, I would agree.

The bottom line, for me, is this:

- vdH recommends a percentage of VTF for anti-skate
- SME uses a percentage of VTF for anti-skate
- my experiments with the blank disc show two things:
a) that the wires exert a force of their own which is independent on VTF; and
b) that anti-skate requirements will vary with VTF
(the higher the VTF, the faster the arm will glide, and the more anti-skate it will require).
So, yes, a blank disc is invaluable, to understand mechanical behavior.
They all seem to paint the same picture: some anti-skate is required and it's dependent on VTF plus stylus shape as others pointed out (including vdH). The "how much force" should really be left to the ear, and the thing to look for is reduced distortion.
 
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PeterA

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Here is a photo of the anti skate (bias) instructions from my SME 3012R manual. You can see clearly how values are calibrated and marked on the diagram. I set mine at 0.5g, or 1/3 of the VTF of my vdH cartridge. That is the innermost indentation on the bias lever. Super easy and no guess work. It would be nice if all manufacturers had such easy to follow instructions. My SME V-12 uses a damped spring and numbered dial. I also set that at 1/3 of VTF, in my case, again at 0.5g for my other vdH cartridge. I have listened for changes in sound between values of roughly 0.25 - 1.0g on the V-12 and between 0.5-1.5g on the 3012R. 0.5g seems to work well in my case.


IMG_0214.JPG
 
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jadis

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Phil, let me see if I can address these questions in a simple way, and please bear with me...

1) Regarding the "how much anti-skate force do I exert": on the VPI arm, and because the anti-skate device is rotational as shown below, it will require some math. Below is the anti-skate at the lead-in and lead-out grooves, and as you can tell, it will vary slightly, with less force applied at the lead-out grooves because of the angle of the anti-skate lever:

View attachment 65037

View attachment 65038

Those rubber weights are 0.116g each, and five of those give me (as I said yesterday) roughly 0.6g that I wanted to apply. However, because this is a lever device, the actual force exerted mathematically depends on the offset of those weights away from the pivot point (that screw) - the further away, the more the force. In my case, since I have five, the distance is averaged out and is calculated based on the 3rd disc. In addition, the other arm has significant mass of its own, which would further reduce the anti-skate force, when it rotates

I did some measurements and rough calculations, and the maximum force (in the lead-in grooves) would be roughly 28% the VTF of 2.3, or 0.65g, very close to the ratio vdH recommends.

Now, regarding the varying force as the arm moves and anti-skate rotates... one might be tempted to say that this device, as is, is flawed; however, there is at least one more parameter here, and that is the wires coming out of the arm as shown below, which as I mentioned yesterday, I can demonstrate with the blank disc that they have an anti-skate effect of their own, at various places along the tracing arc. What actually happens is that those wires ADD additional anti-skate force towards the center of the disc, and therefore, the rotational anti-skate device's reduced force compensates for that. Again, the blank disc has been very valuable in figuring out all kinds of things about mechanical behavior.

All in all, the end result is closer to a linear *total* anti-skating force across the tracing arc than I had originally thought. This being vinyl analog, EVERYTHING is an approximation, and here we are.

View attachment 65039

2) Regarding the question about where to put that anti-skate thread: I use the position which results in the least rotational travel, for minimal variability in the force

3) Regarding the question, well, how do I know how much actual force am I applying with any arm, or those arms with a dial: I don't think you can, at least not easily. In my case again, I *think* I have fairly correctly calculated it, but I am not sure it's entirely accurate

4) Regarding your guess that those rotational dials differ from arm to arm: yes, I would agree.

The bottom line, for me, is this:

- vdH recommends a percentage of VTF for anti-skate
- SME uses a percentage of VTF for anti-skate
- my experiments with the blank disc show two things:
a) that the wires exert a force of their own which is independent on VTF; and
b) that anti-skate requirements will vary with VTF
(the higher the VTF, the faster the arm will glide, and the more anti-skate it will require).
So, yes, a blank disc is invaluable, to understand mechanical behavior.
They all seem to paint the same picture: some anti-skate is required and it's dependent on VTF plus stylus shape as others pointed out (including vdH). The "how much force" should really be left to the ear, and the thing to look for is reduced distortion.
Thanks for your very detailed explanation, Tasos. Very well expounded and it's quite clear to me now, re your AS device and how it works. It's good to know that you are getting good use from it, and that is a very good thing.
 
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(...) The "how much force" should really be left to the ear, and the thing to look for is reduced distortion.
I would add : The "how much force" should really be left to the ear, if you do not have access to a proper LP and a stereo distortion meter or a proper system such as Adjust+ .

I have used the HiFi News test LPs and Spectraplus with success for antiskating setting - it gives the same value as ear, and is much faster and reliable.
 
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ack

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I would add : The "how much force" should really be left to the ear, if you do not have access to a proper LP and a stereo distortion meter or a proper system such as Adjust+ .

I have used the HiFi News test LPs and Spectraplus with success for antiskating setting - it gives the same value as ear, and is much faster and reliable.
I agree. More of us need to embrace Adjust+ for all kinds of adjustments
 

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