How much weight is enough to damage vinyl?

[Pazuzu]

There's one scenario being missed here. You're called out of the room while an LP is playing, or worse still you completely forget you've got one playing. The stylus eventually arrives at the lead out groove and continues, ad infinitum, to circle around that same grove over and over again. As with the cave man's technique of rubbing two sticks together to start a fire, is it possible that a stylus circling over and over on the same narrow stretch can eventually heat up the vinyl? I have no idea - anyone care to comment?

Stumbled across this forum while looking for info.

I wanted to chime in on what happened to me once.

Back in the late '80's, I had an old turntable that didn't do the automatic stop thing. I once fell asleep on a 45. The stylus spun around the lead out groove for a good 4-5 hours. What was left was a record covered with a fine, white dust and a stylus that never sounded good again.

So, I don't know if it heated up the vinyl, but it defiantly pulled material out of the groove.

And now that I think of it, I don't think the 45 was real vinyl, I think it was one of those translucent (when held up to light) plasticy pressings. So take that as you will.

[Ldg]

Static indentation of vinyl doesn't count, it's nothing like the dynamic of a contact area traversing 300,000x it's own width per second !

Ye believers in compressed vinyl, suggest do the sums and work out how much energy is left behind the stylus, stored in compressed vinyl, and try to reconcile that with what's available from stylus friction/drag force ! It doesn't happen ! The stylus planes the surface at all reasonable VTFs, like some sonic surfer !

High pressure in the stylus contact area is effectively spread over a continuously changing groove wall area. Same reason a surfer doesn't sink. The diamond has high pressure constantly, whereas a given section of groove wall only instantaneously, not long enough to compress.

[flavio81]

There's one scenario being missed here. You're called out of the room while an LP is playing, or worse still you completely forget you've got one playing. The stylus eventually arrives at the lead out groove and continues, ad infinitum, to circle around that same grove over and over again. As with the cave man's technique of rubbing two sticks together to start a fire, is it possible that a stylus circling over and over on the same narrow stretch can eventually heat up the vinyl? I have no idea - anyone care to comment?

No, this can't happen. Scientific calcs show that there is not enough energy available at the stylus tip for this to happen. Ask ld.

[flavio81]

Relevant to this thread is to continue reading / discussing on this other thread.

http://www.vinylengine.com/phpBB2/viewt ... sc&start=0

[Whitneyville]

Flavio, the Edison cylinders used 1/4 lb of stylus pressure on a nominal 3-5 mil steel (100 for 5 cents) or stetitte (tungsten carbide) (20 for a dime) stylus. I clean my used LP's by playing them on an automatic turntable over and over and over at 5 grams, and plow up a pile of crud from the grooves. they always sound better afterwards too. The Denon 103 is all the proof needed that high VTF isn't the "Bogey-Man" we thought it was. The "transparent/translucent" 45's and 33's are made of polystyrene monomer and they DO wear quickly, FROM DIRT! I have a 1958 Coe (Portales, TX) recording of the "Temple Quartet" on a red styrene LP and it plays and sounds like new, and I KNOW I've played it 5 or 6 THOUSAND times mostly on a 1950 Zenith Cobra-Matic record-changer with a 1 mil stylus (red/green) and 7 grams+ VTF. I played this morning at 1:45AM. I played "Southern Gospel" (The Lefebers, the Happy Goodmans, Vestal Goodman, The Inspirations, The Hemphills and the Singing Rambos) until 5 AM...all LP's, newest, 1976.

[electrokid]

Hi Folks,
Just found this forum and felt I had to reply to this subject...

In the 1960s my parents didn't have a record player and I didn't have the money to buy one so I scrounged a turntable and cartridge - but had to make the arm out of ally tubing. The percieved wisdom at the time was that accurate tracking was king and it didn't matter too much how great the tracking weight - so that's how I initially set up the arm.

I bought a single... then I bought an LP - a very cheap LP - Vivavdi's Four Seasons - plugged into the gram input it all sounded ok by 1960s standards.

After a while I got hold of a device to measure tracking weight - it was capable of measuring up to 15 grams - I still couldn't measure the tracking force - it was over 15 grams ! ! ! But then some crystal cartridges had the compliance of a house-brick.

So - long story short - having played that LP quite a lot with a very high tracking force - I still play that LP these days - and it sounds fine - I'd say that any wear was minimal. Though since the 1970s it has had the luxury of being played on a decent turntable with an SME arm and a JVC 4MD-10X cartridge tracking at a far more sensible 1.5 grams

[KentT]

On the Audio-Technica ATP series and SME 3009 and 3012, we tracked 680 EL all day at 2 grams with no tracking issues when set up correctly. Record wear was minimal if any over many playings.

[dlaloum]

The Shure Technical seminar paper provides actual wear data from lab measurements....

http://shure.custhelp.com/app/answers/d ... aWhZbGs%3D

The conclusions with regards to record wear are cautious....

But the one unambivalent statement they definitely make is that mistracking will damage the vinyl (so even tiny amounts of mistracking are to be avoided!). Whereas wear is a complex and tricky subject on which they cautiously make no definite statement - although their data appears to indicate that line contact styli and lower VTF do reduce wear.

If you have to choose between lower vtf with marginal (tiny amounts of) mistracking or higher VTF with no mistracking - pick the higher VTF!!

bye for now

David

[Ldg]

The Shure Technical seminar paper provides actual wear data from lab measurements.... although their data appears to indicate that line contact styli (..) do reduce wear.

Well no, that Shure technical marketing compilation does not actually provide wear data from lab measurements per se. Neither does it imply that line contact styli reduce wear. In fact, it concludes "The results showed no significant difference among biradial, hyperbolic, and hyperelliptical tips."

Here is what the article says as to vinyl wear :

Our tests have shown that inadequate trackability, that is to say high mechanical stylus impedance, is by far the largest contributor to premature record wear or damage. In no way can a tip, no matter how well it is designed, prevent this type of irreparable damage. Examination of properly tracked grooves at 300 times magnification and greater has revealed that some modification to the groove is always visually detectable, regardless of the cartridge or the tip. A slight depression or shallow "trough" resulting from permanent indentation of the groove wall takes form in the first few plays. For most recorded signals, that amount of indentation does not significantly modify the reproduced signal. Assuming proper tracking and good record material, the "trough" is seemingly little changed after 50 or even 100 plays. In fact, some small amount of indentation is desirable to smooth roughness or irregularities in the surface of the groove wall, thereby keeping the surface noise low. In designing a tip, however, we would like to know how different tip geometries affect the shape of the record modulation with increasing numbers of plays. To do this, we have made many distortion tests. Following are some typical test results ...(..)....

......The results were highly variable among the tips with distortion levels sometimes increasing and sometimes decreasing. A decrease in distortion may be as much an indication of groove wear as an increase. The tip may hare modified the groove such that the distortion generated by record wear partially canceled distortion from other sources. No change in distortion indicates the least amount of record wear. 0n an average, the tests indicate a trend favoring the long contact tip, however, the benefit is highly dependent on the particular signal and the tracking force.

We have presented these examples to emphasize the variability of data and difficulty of obtaining conclusive results. Conclusions as to the quantitative effects on wear must be drawn with great care.

...(..)...Record wear tests were conducted as well. Second harmonic distortion was measured after 100 plays as outlined in the previous paper..... The results showed no significant difference among biradial, hyperbolic, and hyperelliptical tips.

To turn it round, if line contact tips have lower wear, why would it be difficult to obtain conclusive results ? If there were no notable difference between tip types it might be difficult, that I can see.......!!

I venture these papers suggest there is no signifant difference in record wear between tips. It is also virtually silent on any relationship between VTF and record wear, FWIW.

[dlaloum]

From the Technical seminar document... the results which the conclusions were based on:

Test 1: 2nd and 3rd harmonic distortion versus number of plays
Cartridge: V15 Type III
Tips: biradial and hyperbolic
Signal: CBS STR-100, bands 3A and 3B, 1 kHz
Tracking Force: 0.75 gram
Number of Plays: 100
Results: 2nd harmonic with biradial: no significant change on either channel.
2nd harmonic with hyperbolic: no significant change on either channel.
3rd harmonic with biradial: decreases about 33% of original value.
3rd harmonic with hyperbolic: decreases about 40% of original value.
Test 2: Same as Test 1 but at a tracking force of 1.5 grams.
Results: 2nd harmonic with biradial: increases by an average of 20% from original value.
2nd harmonic with hyperbolic: decreases by an average of 40% from original value.
3rd harmonic with biradial: decreases by about 33% from original value.
3rd harmonic with hyperbolic: decreases by about 33% from original value.
Test 3: Same as Test 1 except at 6 kHz.
Tips: biradial and hyperbolic
Signal: CBS STR-100, bands 3A and 3B, 6 kHz
Tracking Force: 0.75 gram
Results: 2nd harmonic with biradial: increases an average of 48% from original value.
2nd harmonic with hyperbolic: increases an average of 40% from original value.
3rd harmonic with biradial: increases an average of 40% from original value.
3rd harmonic with hyperbolic: decreases an average of 66% from original value.
Additional Notes: The changes in distortion values for styli from both groups exhibit decreases as well as increases. Decreases as great as 30% and increases of over 100% were measured.

Test 4: Same as Test 3 but at a tracking force of 1.5 grams.
Results: 2nd harmonic with biradial: average of both channels increases about 66% from original values.
2nd harmonic with hyperbolic: average of both channels increases about 25% from original values.
3rd harmonic with biradial: both channels increase an average of 45%.
3rd harmonic with hyperbolic: both channels decrease an average of 30%.

Additional Notes: Average initial 3rd harmonic distortion was higher with hyperbolic tips than with biradials, but final average 3rd harmonic distortion is about 25% lower with hyperbolic tips.

Variables in this test are:
1) VTF
2) Eliptical vs Hyperbolic (line contact) stylus
3) Frequency measured

My reading of the results, is that the hyperbolic tip appears to consistently provide better distortion results than the eliptical (bi-radial).
It is not clear whether this is due to reduced wear, or whether the wear is the same, but the line contact stylus has a lower distortion when reading a worn groove....

The chapter before this one discusses stylus wear, and one does tend to feel (intuitively) that where there is lower stylus wear showing reduced friction, there must also be reduced vinyl wear.
However there is no matching data to either confirm or deny this intuition here.

Great paper to read in any case!

bye for now

David

[Ldg]

My reading of the results, is that the hyperbolic tip appears to consistently provide better distortion results than the eliptical (bi-radial).
It is not clear whether this is due to reduced wear, or whether the wear is the same, but the line contact stylus has a lower distortion when reading a worn groove....

Even Shure acknowledge "The results showed no significant difference among biradial, hyperbolic, and hyperelliptical tips."

NB in this method, decreases as well as increases in distortion are both associated with wear, the magnitude of change is the indicator. Low wear means low change from initial value. Marking how much the groove has changed from its initial shape.

Examples that contradict your position, DL :

Results: 2nd harmonic with biradial: no significant change on either channel.
2nd harmonic with hyperbolic: no significant change on either channel.

3rd harmonic with biradial: decreases about 33% of original value.
3rd harmonic with hyperbolic: decreases about 40% of original value.

3rd harmonic with biradial: decreases by about 33% from original value.
3rd harmonic with hyperbolic: decreases by about 33% from original value.

etc etc

Actually, the results are fairly all over the place. On this occasion I agree with Shure's position : "The results showed no significant difference among biradial, hyperbolic, and hyperelliptical tips."

The chapter before this one discusses stylus wear, and one does tend to feel (intuitively) that where there is lower stylus wear showing reduced friction, there must also be reduced vinyl wear.
However there is no matching data to either confirm or deny this intuition here.

I certainly don't share that intuition. And, if it were true, it would be pretty straightforward to demonstrate. Shure had motivation to do so if it were at all possible. But couldn't. I venture that is simply because there is "no significant difference among biradial, hyperbolic, and hyperelliptical tips." That's an entirely fair and reasonable interpretation here !

[dlaloum]

LD did I miss something?

Results: 2nd harmonic with biradial: no significant change on either channel.
2nd harmonic with hyperbolic: no significant change on either channel.

In this case no significant change.

3rd harmonic with biradial: decreases about 33% of original value.
3rd harmonic with hyperbolic: decreases about 40% of original value.

In this case 3rd harmonic distortion decreases more with line contact - advantage line contact.

3rd harmonic with biradial: decreases by about 33% from original value.
3rd harmonic with hyperbolic: decreases by about 33% from original value.

[/quote]
No significant difference.

Test 4: Same as Test 3 but at a tracking force of 1.5 grams.
Results: 2nd harmonic with biradial: average of both channels increases about 66% from original values.
2nd harmonic with hyperbolic: average of both channels increases about 25% from original values.
3rd harmonic with biradial: both channels increase an average of 45%.
3rd harmonic with hyperbolic: both channels decrease an average of 30%.

Again lower distortion with the Line contact stylus.

Going through the results, the line contact shows consistently lower distortion than the biradial.... (regardless of whether there was an increase or decrease in distortion, the end result always shows the LC tip either increasing less, decreasing more, or staying the same as the eliptical - it is never worse off)

The pattern of distortion variance however is not clear... I agree. So Shure point to that and say that they cannot make a conclusion with regards to wear based on this data.

What I am saying is not related directly to wear - but I am stating that the resulting output after 100plays will be lower in harmonic distortion content when using a Line Contact stylus in most cases, and is unlikely to be worse.

Clearly they were looking for and expecting a difference (so their intuition was the same as mine) - the results were inconclusive for wear (not for distortion... for wear), which they stated.

As they pointed out:

A decrease in distortion may be as much an indication of groove wear as an increase. The tip may have modified the groove such that the distortion generated by record wear partially canceled distortion from other sources. No change in distortion indicates the least amount of record wear. 0n an average, the tests indicate a trend favoring the long contact tip, however, the benefit is highly dependent on the particular signal and the tracking force.

What they could not find was a consistent trend minimising change (hence minimising wear) - but what they did find was a trend favouring the LC "on average".

Their conclusion is that tip shape does not have a clear consistent relationship with wear - fair enough.
The test was not however, trying to measure a relationship between VTF and wear. - Which is a shame! - leaves us with intuition again.

bye for now

David

[Ldg]

LD did I miss something?

Yes. You missed that it's the magnitude of change that indicates extent of wear. Rather than whether its an increase or decrease. Put it like this, the groove has a different shape after the test either way. So the groove has changed shape, which is wear. Don't blame me, it's Shure's method.

And by that criteria, "The results showed no significant difference among biradial, hyperbolic, and hyperelliptical tips." Which is true.

Plus you missed that wear is always bad !

It is untrue that a line contact stylus showed lower distortion than the biradial in this test, for two obvious reasons. Firstly, we only know the change, not the absolute level. Secondly, 'distortion' in the sense you mean can be defined as how different the 'after' is than the 'before' - which we do know - and by this criteria 'distortion' is not significantly different between tip types. In fact, it's all over the place.

What I am saying is not related directly to wear - but I am stating that the resulting output after 100plays will be lower in harmonic distortion content when using a Line Contact stylus in most cases, and is unlikely to be worse.

What ?? You are actually suggesting that playing records 100 times with a line contact stylus somehow improves distortion, DL ? That's statutory counterintuitive....... and it's nonsense, of course. For the reasons set out above, that's not what the results mean at all, you've simply misinterpreted.

Clearly they were looking for and expecting a difference (so their intuition was the same as mine) - the results were inconclusive for wear (not for distortion... for wear), which they stated.

That's what happens when one tries to shoehorn an expectation into a test. It doesn't always fit, and generally can't be made to when it doesn't. But the result should be accepted for what it is, if one cares about exploring the truth rather than proving an expectation.

The test was not however, trying to measure a relationship between VTF and wear. - Which is a shame! - leaves us with intuition again.

Your intuition that lower tip wear = lower record wear could well be wrong too, for example, if the contact location moves about more on a line contact stylus. Think about it. Contact location at a fixed moment on a groove is always the same, it's repeatable for say 100 plays. But contact location on the stylus varies with modulation, ie it varies for different groove 'moments'. So tip wear is lower the more the contact location varies, but groove wear at a point on the record is the same.

Shure : "The results showed no significant difference among biradial, hyperbolic, and hyperelliptical tips." No more and no less !

[flavio81]

David (dlaloum), i think you're reading far too much into that "test".

If you want to research the topic there are far better studies that have been done BEFORE the above cited marketing blurb.

Anyways, i don't care for wear at all. I haven't worn any record even when using a cartridge of 4 grams VTF. No audible change.