How much weight is enough to damage vinyl?

the thin end of the wedge
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orlandoscarpa
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How much weight is enough to damage vinyl?

Post by orlandoscarpa » 08 May 2008 02:03

Hey everyone, just registered here on vinylengine! A few weeks ago, maybe a month, i started to get into vinyl. I have adjusted VTA, Azimuth, aligned my cart, all that stuff. My turntable is a Sansui SR 929 with a Stanton 680 EL cartridge.
The recomended tracking force for my cart is 2 - 5 grams. I decided to go with 3.4. Although it appeared to be tracking well at 2,9, i thought maybe it may be a little to light. My cart is a Stanton 680 EL, can't afford to upgrade at the moment, not even the stylus.

Even with alignment, VTA and azimuth set correctly, is 3,4 enough to cause long term record damage? Just how long is long term?
Is there a definitive way to know if 2,9 grams is to light? 3,4 to heavy? I've heard about test lps, but can't afford them at the moment either.

This vinyl thing is harder than it seemed to be!

I am currently satisfied with it's sound, even if it is mid-fi. My only real concern is about the damage it may cause!


PS: sorry about a few grammer and spelling mistakes, english is my second language!

bauzace50
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Post by bauzace50 » 08 May 2008 02:17

Hello orlandoscarpa,
Welcome! Benvenuto! The simple reply: setting the tracking pressure at, or near, the heaviest specified pressure is the best option for record wear with each cartridge. That is the general rule, and easy answer.
There are many other considerations which you can study later on, to expand your knowledge and understanding of this complicated hobby. Several other members are surely glad to come in and begin to explain the scientific and complicated aspects of your question.
Good luck, and let us know how you are doing,
bauzace50

analogaudio
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Post by analogaudio » 08 May 2008 04:54

I would like to give you a different opinion :D

The technical literature that I have read states that when the playing weight is 1 gram that wear is virtually eliminated. There was much work done in the 1960s and 1970s to produce cartridges that track at these low weights, the older cartridges that required 3, 5 or 10 grams were stiffer and put more force on the groove wall which increased the wear rate, the newer cartridges worked with much less weight 1 to 3 grams typically but they also needed to be used in low mass arms to operate satsifactorily.

I think what makes people cautious of the lower weight and to recommend using the higher weight is concern over mistracking when noticeable distortion begins to appear. Some believe that mistracking at low weights is worse than not mistracking but with higher weights. I believe the opposite is true, that tracking at higher weight always causes more rapid wear. Wear is an increase of the background noise and some loss of high frequencies.

If the TT and cart are set up correctly, the stylus is in good condition and the playing weight is as close to 1 gram as possible then there is very little wear. When wear ocurs it is usually gradual, it is a little more each time the the disc is played. Wear produces a slight increase in the background noise and possibly some loss of the high frequency signal.

There is something else that happens with a worn stylus that is more correctly called damage not wear, that is when the groove is played only once with a worn stylus the groove can be permanently damaged causing an increase in distortion and loss of high frequencies. For this reason it is important to replace the stylus, the recommendation used to be that a diamond stylus lasts maybe 1000 LP sides.

Ted

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Post by Axon » 08 May 2008 06:47

Discussion about tracking weight is pretty much meaningless without also discussing the stylus profile; the contact area varies dramatically between a 0.7 mil spherical, all of the various "elliptical" profiles, MicroLine, etc. It's not the tracking force itself that causes wear, it's the pressure. Stylii with small contact areas will exert more pressure than stylii with large contact areas with the same tracking force.

Put another way, 3 grams with one cartridge may not cause any damage, but 2 grams with another cartridge might.

I'd just stick with whatever the manufacturer recommends. They paid a lot of engineers very well to come up with numbers that took all the factors into account.

If you still feel paranoid about it though, if you didn't buy the 680EL new, then the very first thing you should do is buy a new cartridge. None of this discussion of tracking force matters if your stylus is worn.

orlandoscarpa
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Post by orlandoscarpa » 08 May 2008 07:31

Axon wrote:Discussion about tracking weight is pretty much meaningless without also discussing the stylus profile; the contact area varies dramatically between a 0.7 mil spherical, all of the various "elliptical" profiles, MicroLine, etc. It's not the tracking force itself that causes wear, it's the pressure. Stylii with small contact areas will exert more pressure than stylii with large contact areas with the same tracking force.

Put another way, 3 grams with one cartridge may not cause any damage, but 2 grams with another cartridge might.

I'd just stick with whatever the manufacturer recommends. They paid a lot of engineers very well to come up with numbers that took all the factors into account.

If you still feel paranoid about it though, if you didn't buy the 680EL new, then the very first thing you should do is buy a new cartridge. None of this discussion of tracking force matters if your stylus is worn.
The cart is used, but the stylus was new, never used.

The stylus type is, acording to the Stanton Webste, eliptical 0.3 x 0.7 mil (Super High Polish).
The manufacturer recomends 2 - 5g, that's a pretty big gap. My concern is that 2/2,5 may not be heavy enough!

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Post by bauzace50 » 08 May 2008 08:44

orlando,
Both Analogaudio and Axon are correct! But this discussion is now beginning to go into studying the desirable characteristics of the ideal cartridge, which is not the one you have. Your cartridge is clearly designed for the Disc Jockey.
Analogaudio's reply would advocate looking for a cartridge which would track well at one gram. But that is not the one you have.
Axon and myself would advocate the tracking pressure specified for your cartridge (680 EL) according to the manufacturer.
Now you have two apparently conflicting answers, both of which seem incompatible and contrary. Mutually exclusive.
But the answer for your specific 680 EL cartridge is a compromised value imposed by the specific design of your cartridge. Preferably at the higher end of the manufacturer's recommendation.
The ideal theoretical pressure of one gram or less is not possible with the vast majority of cartridges on the market today! They would damage the vinyl more at one gram, than at the higher values recommended by the cartridge manufacturer.
The 680EL cartridge is best used toward the high end of its pressure specifications. BUT Analogaudio's recommendation would motivate you to eventually Choose Another Cartridge capable of tracking at the ideal of one gram or less. That is the ideal you could strive for, but it is not the cartridge you have right now.
Other enthusiasts would debate the actual choice of one gram as the ideal, as Axon states. There even are "audiophile"cartridges designed to track above two grams, and are claimed NOT to damage vinyl at that setting!
Good luck. bauzace50

Guest

Post by Guest » 08 May 2008 10:04

analogaudio wrote:I would like to give you a different opinion :D

I think what makes people cautious of the lower weight and to recommend using the higher weight is concern over mistracking when noticeable distortion begins to appear. Some believe that mistracking at low weights is worse than not mistracking but with higher weights. I believe the opposite is true, that tracking at higher weight always causes more rapid wear. Wear is an increase of the background noise and some loss of high frequencies.

Ted
Hi,

Mistracking at low stylus forces causes permanent damage to the groove
walls and is far worse than the "extra" wear due to a higher tracking force.

You seem to be suggesting some mistracking is a safer bet than no
mistracking - ????? - I could not agree less. Towards the top end of
a cartridges recommended tracking force range is always best IME.


Klaus R.
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Post by Klaus R. » 09 May 2008 07:26

Here's what literature has to say with respect to record wear:

1 mil = 1 thou = 25.4 microns (1/1000 inch)

===============================================

1. Barlow, Groove deformation in gramophone records, 1958

Limiting load for plastic deformation for a 1 mil tip in a 90 deg groove is
0.64 gr. A 0.5 mil tip presents a side contact area of 23.4 square microns (from Davies below).

2. Flom, The deformation of plastics with hard, spherical indenters, J. of Audio Eng. Soc. 1959, p.122

Plastic deformation on vinyl occurs for a 0.005 cm stylus at 5 grams static
load.

3. Walton, Gramophone record deformation, Wireless World 1961, July, p.353

Shows a graph with VTF vs stylus radius : plastic deformation is caused for spherical styli of 0.0003 inch at 2.1 gr deformation, 0.0004 inch 2.7 gr, 0.0005 inch 3.1 gr etc.

4. Anderson, Some aspects of wear and calibration of test records, J. of Audio Eng. Soc. 1961, p.111

Investigation concerning the wear occasioned by the initial playing of test
records at various needle forces.
Frequency response curves were taken to show high frequency wear. The first playing, especially at high VTF, accomplishes a large part of the wear observed after 20 plays. A first play at 9 grams had worn off 1.5 dB. For the same standard M3D cartridge at 9 gr a drop of 5 dB at 15 kHz occured, at 6 gr 2 dB, at 3 gr no drop , all drops indicated after 20 plays

Results : the first playing, especially at high tracking force, accomplishes
a large part of the wear observed after 20 plays.
Wear drops rapidly as tracking force is reduced. Measured was frequency
response; it turned out that the response dropped by up to 5 dB at 15 kHz, indicating high frequency wear.

5. Oakley, Inner groove distortion, Audio Magazine 1962, June, p.57

For 0.5 mil styli a VTF of more than 3 grams tends to erase high frequencies
6. Hunt, The rational design of phonograph pickups, J. of Audio Eng. Soc. 1962, p.274

One of the resonances present in the system is the stylus groove resonance which is difficult to suppress. It's maximum is especially in the
intermediate portions of the stylus suspension. The transducing mechanism is sensing motion in that portions so that the resonance will appear in the electrical output of te cartridge as spurious response.

Solutions are either to locate such resonance above the audible range or to apply damping.
Damping is ordinarily chosen. This damping, however, leads to overdamping at frequencies other than the resonance frequency. An additional force is thus exerted on the stylus in the
mid frequency range. The increased force leads to increased frictional work and to increased wear.

7. Walton, Stylus mass and reproduction distortion, Wireless World 1963, April p.171

Pictures of stereo grooves played with pickup at 2.7 gr VTF (stylus mass 3
mg). Permanent indent depth = half modulation depth. After 5 playings, little further deformation is visible. Low effective tip mass is advantageous.
8. Kogen, The elliptical stylus, Audio Magazine 1964, May, p.33

VTF for 0.2 mil 0.9 mil elliptical stylus should be no greater than 1.5
grams.

Frequency response :

0.2 mil elliptical tip
no change at 1 gr VTF
slight change between 10 20 kHz at 1.5 gr after 100 plays
significant change between 10- 20 kHz at 3 gr

0.7 mil circular tip
slight change between 10-20 Khz at 3 gr after 100 plays

More wear because of smaller contact area for the elliptical tip.

A record played at 1.5 gr with 0.2 mil elliptical tip showed signs of wear
under microscope, but this wear was not detectable in the sound.

9. Barlow, Groove deformation in gramophone records, Wireless World 1964, p.160

Presents a 1 thou radius stylus under increasing static load : not
calculated but observed at 12 mg, fully elastic range
at 0.5 gr, plastic deformation just reaching the surface
at 2.5 gr, fully plastic range

10. Bastiaans, Factors effecting the stylus/groove relationship in
phonograph playback systems, J. of Audio Eng. Soc. 1967, p.389

Yield point of record plastics = 14,500 psi. He refers to older papers
saying that in the stylus/groove contact, sub surface yielding begins near a load of 0.150 gr and plastic yielding at 1 1.6 gr (for a 17.8 mil tip). Microscopic examination of a groove played with 2 gr VTF revealed a slight permanent indentation track on both groove walls.

11. Anderson, Phonograph reproduction Audio Magazine 1978, May, p.3 (pt.1), June, p.42 (pt. 2)

Tracing distortion relates to size and geometry of the stylus tip.
Distortion decreases and wear increases with decreasing tracing radius of
the tip. Record wear is related to tracking force and trackability. Minimum
distortion results from a tip of 5 microns. This demands a VTF of lower than 1.5 grams. By well designed shape of the tip the tracing radius gets small without having a too small contact area. The contact area is related to indentation and stress in the groove wall, thus influencing wear.
Tests were carried out with the version IV cart with biradial, hyperbolic
and hyperelliptical (25.4 x 38 microns) tips. As far as record wear is
concerned, no difference between the tips was found, when playing with 1.25 grams.

They further state that at that time, there was no measured evidence that
the use of a long contact area stylus (van den Hul, fine line, micro line, microridge = 3.8 x 76 microns ) allowed to play with more than 1.5 grams without affecting record life.

12. Pramanik, Understanding phono cartridges, Audio Magazine 1979, March, p.33

Record wear in UNMODULATED grooves starts at about 3 gr. Wear is not only directly attributed to VTF, but also on friction between the tip and the groove wall.
A correctly shaped and well polished tip does not cause wear.

The compliance is determined by stiffness of the elastomer cantilever
suspension and the cantilever length. Elastomer stiffness is not constant, but varies with frequency. With increasing frequency compliance decreases (becomes stiffer).
The suspension exerts a force attempting to restore the stylus assembly to its mean position (the optimum position for what the stylus was designed for). The stiffer the suspension (the lower the compliance) , the larger is that force. VTF must be at least as large as the restoring force in order to maintaining contact with the record.

Starting from the mean (design) position:
1. when the stylus attempts to move below the mean position, the cantilever restoring force tries to move it upwards. Here VTF comes into play to avoid that the tip loses contact.
If VTF is too low or smaller than the restoring force, the stylus will loose
contact and cause severe damage when bouncing back into the groove.
2. when the stylus attempts to move above the mean position, the total force on the record is the sum of restoring force and VTF.
If compliance is low and, as a consequence, VTF is rather high to maintain
contact with the record for the largest amplitudes to be found (low frequency trackability), the sum of forces can be so large as to result in stylus pressure that deforms the groove into the plastic region, causing permanent damage.

As far as effective tip mass (ETM) is concerned, it plays a role in the high
frequency region, where acceleration is high. VTF must be at least as large as the force defined by ETM (F=m x a) and the largest acceleration on the record.
If VTF is too low, the stylus again will loose contact.
Even when VTF is adequate, the pressure on the tip when on the bottom of the groove is due to the sum of forces required to accelerate ETM and the VTF, which is constant. The larger ETM, the higher the forces and the higher the pressure exerted on the groove which may be sufficient to cause plastic deformation.

So one has an interest to have a cartridge with low ETM and rather high
compliance to avoid high VTF.

13.Davies, Close up look of record wear, Audio Magazine 1980, Sept., p.38

Scanning electron microscope study for Shure's M91ED cartridge with 1 gr VTF and a not specified MC with 2.5 VTF (records were played 50 times) on high quality audiophile record.
Even the unplayed record showed signs of surface imperfections, e.g. holes.

Shure : photos show audible loss of quality. Pieces of vinyl have come off
the surface. Distinct wear lines can be seen parallel to the groove. The
type of damage caused is termed surface conchoidal fracture, resembling
broken of shattered glass. The groove surface reminds glass surfaces being chipped by fine sand.

Another record shows enormous damage after 50 plays, showing the same type of damage and many longitudinal wear lines.

MC : tearing and gouging wear is predominant (dust as grinding agent).

All styli present pressures of 30.000 to 69.000 psi with a VTF of 1 gr.
These high pressures have led people to assume that plastic or permanent deformation occurs, the yield point of the vinyl being 14.500 psi. Static indentations in the elastic range can be described by the equation of Hertz.
It appears that no solution exists for the plastic range, especially for
sliding indentation with friction.

The study found that the quality of the vinyl plays an important role as far
as sound quality is concerned. In particular the filler material used is of great importance, it seems that it has tendency to split off. Dust in the groove is pushed and pounded into the groove wall, scouring and gouging the wall.

==============================================


It seems to be a common practice of pickup designers to select first the
mode of transduction, then to choose the kind and size of associated
vibratory structure on the basis of convenience or necessity, and finally to
determine by experiment what bearing weight (VTF) is required for
satisfactory tracking (Hunt, the rational design of cartridges, JAES 1962)

==============================================================================================


Wear is an issue, as I'm able to observe when playing 2nd hand records. Wear is caused by high VTF or mediocre tracking ability of the cartrigdes used by previous owners of that record. I find signs of both.

Klaus

I chose the safe way and bought the Shure V15 with low VTF, great stylus contact area and good trackability.

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Post by bauzace50 » 09 May 2008 13:24

@ Klaus,
it's great to have accurate information! Thanks!
bauzace50

Bebé Tonto

Post by Bebé Tonto » 13 Nov 2009 19:20

Reopening the thread!!

Reading this paper (highly recommended)!
http://www.johana.com/~johana/dorren/cd-4paper4.pdf
The standard was to play the
record 100 times with a conventional low-quality record player using a ceramic cartridge, tracking at 4½
grams.
When testing the CD4 quadraphonic system (which requires delicate 30Khz+ ridges on the grooves), records which were played up to 500 times with a 4.5gr tracking force, played then perfectly on a quadraphonic system, retaining the delicate 30KHz+ carrier.

Of course, those records used a special Q-540 record compound, which is claimed to last "3 times longer" than conventional record compounds. But still, it is a lot!!

Note that the records were played with a Shibata stylus, which is known for playing perfectly otherwise worn records. This is because it reads more of the groove. (See my thread on stylus types). So the record IS WORN if played with a conical or elliptical stylus, because it will read the part of the record that was worn. But when played with a Shibata or Line Contact type, it will play like new.

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Post by 1200y3 » 13 Nov 2009 20:31

I would not go over 3.5 grams for a .7 conical. Less for smaller ones. Most cartridge manufactures stay with a standard, and yours may not be standard. Your stylus compliance can handle large arms, but it better be compliant at 3.5, or you have to raise the force. If that is the case, you should use a stylus that tracks lighter. Wait untill break in is up and then set it low and set it high and compare. If you have a heavy arm, it will need more weight.

Bebé Tonto

Post by Bebé Tonto » 13 Nov 2009 20:46

1200y3 wrote:I would not go over 3.5 grams for a .7 conical.
I wouldn't too.

But the article i cited gives us an idea of vinyl longevity.

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Article

Post by 1200y3 » 13 Nov 2009 23:56

Somebody should come up with information regarding the effects of temperature and time on vinyl. Under proper use the instantaneous melt/freeze principle should take effect. The reason I believe in its importance is from the experience with PVC paint and how time, water, and the elements effect it. Some say it is from washing. Without anything more than just time, paint finishes like such develop tiny microscopic cracks throughout. So if that applies to vinyl, then after the temperature from friction was raised, then damage can take effect with time long after the record has been played. We know records warp when they get warm, and it is shrinkage.

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Post by silviajulieta » 14 Nov 2009 01:40

Dear friends: I'm with Axon post and I would like to add two important factors for we can " conserve " the LP's integrity:

try to mantain in pristine condition ( clean. ) both : the LP and the stylus cartridge.

Regards and enjoy the music,
Raul.

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Post by pivot » 14 Nov 2009 04:13

I know back in the 1970s when I was starting this stuff the idea was to track as light as possible. The ideal seemed to be 1 gram or less VTF.

My first Shure V-15 (series II I think) was set at just around a gram in my GA 212. I recall wondering why dymanic peaks started to sound distorted after a couple plays. Wasn't tracking light supposed to make my discs immune to wear?

Of course I know now that I was getting mistracking. Had I just upped the VTF to 1.25 gram or 1.5 gram distortion and wear would have been reduced.

Trying for super light tracking was the vogue and I wonder how many LPs got chewed up because of it.

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