How much weight is enough to damage vinyl?

[Ldg]

This JVC 4MD-10X stuff is off topic chaps, suggest start a new thread or use PM ?

On topic, I wonder why line contact styli are seldom paired with high VTF suspensions ? It would seem the obvious thing to do, to make the best of line contact tracing geometry.

Obviously, line contact styli become blades, in the limit as minor radius becomes smaller and smaller. That is quite possibly why there are imperical minima as to stylus minor radius. ie there is a practical limit of perhaps 4um which manufacturers do not exceed.

To put it another way, below a certain minor radius, a stylus damages or wears the record groove excessively. Otherwise, all styli would be true line profile as standard by now.

Then it's reasonable to infer that record wear/damage increases as minor radius decreases, for a set VTF and major radius? And perhaps this is a clue as to why line contact profile styli are not often paired with higher VTF suspensions?

In practice, increased wear/damage from decreased minor radius might be mitigated by increased major radius. It's commonly believed that line contact profile has increased surface area contact. However, this does not stand scrutiny, as posted previously on other threads. It would require groove indentation to be significantly higher for line contact types, which contradicts other beliefs held to be true, and the laws of physics to boot !

So, I venture that line contact styli profiles are compromises. In practice, by selecting specific minor and major radii, a manufacturer can devise a profile which offers similar or tolerably adverse groove wear, relative to a biradiall or spherical. If 'tolerably adverse' is chosen, then line contact styli might need to be paired with lower VTF suspensions to attain overall similar record wear to biradial/spherical styli.

This is a candidate explanation for a) why in practice line contact profile styli have no significant difference in record wear and b) why they are generally paired up with lower VTF suspensions.

If so, it's all very clever spin to present line contact tips as a 'low wear' profile. When, by principle and common sense, it's perhaps quite the opposite and has to be compensated or compromised to match other types !

[dlaloum]

Try this:
http://www.ebay.com.au/itm/NEEDLE-STYLU ... 613wt_1185

The MD1016 / 4MD-10x also went by several other names!

[Ldg]

That's blatently off topic, DL, and you could have PM'ed. Intentional ? Read the rules.

[flavio81]

On topic, I wonder why line contact styli are seldom paired with high VTF suspensions ? It would seem the obvious thing to do, to make the best of line contact tracing geometry.

Obviously, line contact styli become blades, in the limit as minor radius becomes smaller and smaller.

Obviously? ld, is that you or someone has stolen your account?
How about the major radius? Do you prefer to be pricked with 100g of vertical force with a sharp pin or with a wide, sharp blade? Which one would you choose?

Also, i think you focus way too much on groove indentation. You can get the same indentation depth, but distribution of the pressure that achieves said distribution is not necessary the same. The contact radius on a Shibata, compared to a similar elliptical is blatantly bigger, for God's sake!! Again, on the "pin vs blade" example, the indentation on your skin can be similar too.

I've already shown an example of high VTF Shibata tips. That most line contact tips are paired with low/mid VTF designs is just a reflection of current market trends, not engineering choices. Audiophiles have lost all traces of manliness and are scared by any VTF over 2.0 gram. Audiophile magazines, manufacturers of cartridges and record care products have a long record of jumping on the "vinyl wear" bandwagon to sell all kinds of ridiculous stuff such as Stylast, record preservatives, Laser turntables and the like.

[dlaloum]

Historical Fencing techniques against bladed weapons include grabbing the cutting edge .... which is much less dangerous than the wee point of a 18th century smallsword.... a thrust from which was quite capable of penetrating very thick leather jackets (ie most armor short of plate) - I'm with flavio on this... the point is more dangerous than the blade. (oops I thought for a second I was on the fencing forum)

[Ldg]

Obviously, line contact styli become blades, in the limit as minor radius becomes smaller and smaller.

Obviously? ld, is that you or someone has stolen your account?
How about the major radius? Do you prefer to be pricked with 100g of vertical force with a sharp pin or with a wide, sharp blade? Which one would you choose?

Yes, it's me
And, I still think this one appeals to common sense.

It's quite possibly why there is a practical lower limit as to minor radius. More to the point (!), a large major radius is required to mitigate the effect of a smaller minor radius. So whether I'd prefer to be pricked with a spherical profile or a line contact profile....neither....my point is they appear to be devised to be about the same 'sharpness'.

But, since there is traceability advantage to smaller minor radii, a manufacturer might prefer a balance toward more wear/damage to take as much geometric advantage as possible. And then mitigate by pairing with a lower VTF suspension. So that's why few line contact tips are paired with higher VTF suspensions, i venture.

Again, on the "pin vs blade" example, the indentation on your skin can be similar too.

Precisely. It seems to be arranged that way, for line contact versus spherical/biradial too.

Audiophiles have lost all traces of manliness and are scared by any VTF over 2.0 gram.

Yes this factor cannot be ignored ! But if wear is adverse, and if one is into conspiracy theories, this would have been manipulated by the industry to to get line contact tips accepted for CD4 et seq

It's always good to see line contact styli in a suspension capable of higher VTF, IMO. It seems a fair endorsement that vinyl wear is generally very low. As I see it, wear is generally very low, irrespective of tip type. It's arranged to be that way, but that doesn't happen naturally though.

Historical Fencing techniques against bladed weapons include grabbing the cutting edge ....

That was the Django Reinhardt school of fencing ?

[v1nn1e]

The point is that we don't drop our stylii straight down onto the musical part of the record groove. The effect is more one of dragging a blade at right angles across the surface, so much more benign anyway, IMHO.

[Ldg]

The blade's not always at right angles, it varies with the signal. So it's more like shaving, where the blade makes an angle of up to 30 deg (depends on the signal). Sharper blades potential cut/scrape rather than glide. Even at right angles though, potential to scrape increases with sharpness. As I see it.

[missan]

The blade's not always at right angles, it varies with the signal. So it's more like shaving, where the blade makes an angle of up to 30 deg (depends on the signal). Sharper blades potential cut/scrape rather than glide. Even at right angles though, potential to scrape increases with sharpness. As I see it.

One question is if the indentation is deep enough to do some scraping? Another thing is where do the mtrls go? I use a rather high force with my Shibatas, without really knowing, it seems fine.
missan

[Ldg]

Hi missan. Yes, I agree that indentation holds many keys to what really goes on at the stylus-groove interface. And I still strongly suspect it doesn't happen to any extent. Rather the stylus surfs the surface no matter what profile, and there's not much wear at all. I think all successful styli have contact profiles that enable this.

Friction, and its nature and origin, must also play its part.

Also, I think that all stylus profiles are devised to have crudely equivalent sharpness and groove wear factors. I also use line contact styli at max+ VTF without wear issues. It seems to me the best of all worlds to have LC styli paired with higher VTF supporting suspensions. Really, I was just mooting a candidate explanation for why there might be so few, because it otherwise seems a very good combination, IMO.

As I see it, there is very little wear in normal use, and so there is no material to be disposed of. No stylus is ever really a 'blade' because design is constrained to avoid it. That's why there are no very small minor radius styli, of course.

[missan]

I agree, fineline and high VTF seems good to me. I have switched the rubber in the suspensions on my Shibatas to a harder one, 2,5gf as nominal.
missan

[dlaloum]

Rather the stylus surfs the surface no matter what profile

A while back I read a post by Peter Ledermann from Soundsmith - in which he put this forward...

That styli in fact "surf" the groove, and further, that they are therefore taking a "sampling" of the groove wall, and not "tracking" it per se!
Which led to a further interesting comment that the system is prone to jitter, same as digital, based on variations in sampling rate, except in the case of vinyl it is generated by variations in tracking changing the sampling rate...

(I am paraphrasing and quoting from memory)

So various techniques that improve the sound, are designed to either improve tracking (sort of self evident) or to make the tracking more consistent... ie: not necessarily better at all points on the record, but more consistent across the entire record under all conditions - eliminate change, which itself is audible.

In any case, the Shure focus on trackability does appear to be correct in terms of wear, the higher the trackability the lower the wear, as most wear and tear issues appear to happen when mistracking and even micro-mistracking happens.

Sure there is a combination of "weight" (VTF), stylus profile, suspension compliance, suspension damping etc... which minimises wear - but does that combination serendipitously coincide with the same combination of parameters that provide the highest possible tracking ability?

bye for now

David

[Ldg]

....Sure there is a combination of "weight" (VTF), stylus profile, suspension compliance, suspension damping etc... which minimises wear - but does that combination serendipitously coincide with the same combination of parameters that provide the highest possible tracking ability?

Well, only in the sense that avoiding mistracking is generally accepted as the best thing one can do to minimise wear/damage. But putting aside wear/damage caused by mistracking for a moment, high trackability and low wear are generally opposed. Trackability improves with increased VTF, for example.

One has to always remember that wear is generally very low anyway, at least for configurations that don't mistrack. So increasing VTF to minimise mistracking without incurring other penalties would seem to be where the payback action is. And this often does seem to be available.

Which led to a further interesting comment that the system is prone to jitter, same as digital, based on variations in sampling rate, except in the case of vinyl it is generated by variations in tracking changing the sampling rate...

There may be a random force element depending on the nature of stylus-groove friction. Specifically the extent to which friction is stick-slip. I suppose that might involve states of bonding and tearing at the groove-stylus interface. Which might imply a potential wear mechanism. Other friction mechanisms might be fluid, or continuous sliding. Which involve little surface bonding, and very little wear/damage. Such things are likely to be influenced by specifics, especially the vinyl itself. Most likely to show up in some form as surface noise, as an indicator. Perhaps.

As one reduces VTF excessively, for a silent groove, crackle/pop surface noise increases. This is perhaps suggestive that at low VTF, stylus-groove friction becomes more stick-slip in nature. Interesting to otherwise explain? In which case, the nature of friction might be VTF dependant, and low VTF more stick-slip in character. And having some 'headroom' for preserving downforce whilst tracking might be advantageous to wear? Favouring configurations with adequate VTF 'headroom'.

[flavio81]

Rather the stylus surfs the surface no matter what profile

A while back I read a post by Peter Ledermann from Soundsmith - in which he put this forward...

That styli in fact "surf" the groove, and further, that they are therefore taking a "sampling" of the groove wall, and not "tracking" it per se!
Which led to a further interesting comment that the system is prone to jitter, same as digital, based on variations in sampling rate, except in the case of vinyl it is generated by variations in tracking changing the sampling rate...

(I am paraphrasing and quoting from memory)

I have read a similar quote by PL. But it is way to vague to convey anything useful.