The Finish Line for your Phono Cartridge- Stylus Wear by Mike Bodell

Discussion in 'Audio Hardware' started by Bill Hart, May 24, 2019.

  1. Dreams266

    Dreams266 Forum Resident

    Location:
    NJ
    My stylus AND cartridge last no more than one year, which at my weekend warrior listening rate, is about 1,000-1,200 hours of play. I have actually noted that my cartridge wears out a little earlier than the stylii. It's funny this was posted now because I recently noted distortion in my mid-range which is beyond the initial warning signs of a worn stylus. I have come to realize that audio probs I'm experiencing almost always are sourced from the stylus/cartridge.
     
  2. Ray Parkhurst

    Ray Parkhurst Well-Known Member

    Location:
    Santa Clara, CA
    Even the pics you provided belie your argument. The LC and SAS styli indeed have a much bigger radius, but it is still a radius. A radius and a line only contact in a single point, but of course when you take vinyl relaxation into account, it becomes a defacto line. It takes some wear before the contact is a true line.

    You say you have seen styli that look very "cone" shaped, but I question your perception on this. You might have been looking at the overall stylus profile and not the very small region at the tip which fits into the groove. Many folks make this mistake, since the region contacting the groove is fairly small compared with the overall stylus profile. The second set of pics you show are artist "concept" sketches, and are far from the reality of what the stylus/groove interface actually looks like.

    Note that there is a very good reason that the stylus tip is curved. Unlike the cutting stylus, which really is cone-shaped all the way to the (presumably sharp) tip, the playing stylus must accommodate a reasonable amount of azimuth variability due to stylus mounting errors, cantilever skew, and cartridge azimuth (sometimes intentional) during installation and setup. The very tips look pretty much like the ones in the first pictures you provided, with a significant curvature to allow multi-degree azimuth errors. Without that curvature, any azimuth error would cause immediate groove damage and uneven wear to the stylus tip. Even with the curvature, the large major radius is much less forgiving of error, making azimuth alignments of LC and MR/SAS types much more critical.
     
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  3. Ray Parkhurst

    Ray Parkhurst Well-Known Member

    Location:
    Santa Clara, CA
    What is it about the cartridge that wears out? I have cartridges from the 70's that have been used (not by me) for thousands and thousands of hours and still work fine with new styli. There are no moving parts in the catridge body, so I am very curious to know what is it that is wearing out?
     
  4. MrRom92

    MrRom92 Forum Supermodel

    Location:
    Long Island, NY
    We have certain members here who often dispute/deny (even conservative) estimates of record wear and it’s audible effects… their absence from this discussion disappoints me.


    Anyhow, carry on with the good work boys. This is important and long overdue experimentation. Even if the results are not entirely favorable and goes against conventional wisdom/more conservative estimates of when a stylus should be replaced... it’s important for us and our collections long-term. Following along with interest though without an electron microscope I’m afraid I can’t contribute much myself.
     
  5. BendBound

    BendBound Forum Resident

    Location:
    Bend, OR
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  6. Ray Parkhurst

    Ray Parkhurst Well-Known Member

    Location:
    Santa Clara, CA
    That paper is a good one. At least it has some relatively believable conclusions, presumably backed up with some data and controlled conditions. But it is not "scientific" in the sense I was looking for. In reality very few papers, even ones published in scientific journals, even ones that have been peer reviewed, actually contain any science.
     
  7. BendBound

    BendBound Forum Resident

    Location:
    Bend, OR
    Disappointed I am not. Why? Too many will say or have said "nonsense" to the established research then wax on about how their cartridge is breaking the 2,00o or 3,000 hour mark and sounding like the day it was installed. Only 95% of them have never had the cartridge examined, but they are locked into their view. It is not supported by research.

    How can you dispute what they say? Instead, I ask them to provide research that establishes their strongly held view. I don't care that a buddy looked at their cartridge and says it is hardly, barely, like not even worn. What would be good is if they re-read what others say who have done the research. Then have their kit properly evaluated. Until they do, how can you take them seriously?

    The reason why I wish they would absorb nuances in the article is for nuggets such as this from James Henriot of Whest Audio who has a business in phono preamps completely dependent on phonograph cartridges. James Henriot of Whest offered to me these lines in an email, now quoting from the "Finish Line":

    “Most (99.9%) ‘audiophiles’ have no idea of what the Shibata line contact profile looks like, so to put a worn one under a 200x microscope is like asking your ‘average Joe’ to remove your kidney with precision.” He notes that the wear pattern is visible ‘face on’ (i.e., front-on) yet virtually all stylus tip images published in audio magazines are taken ‘side on’. Henriot elaborates that to appreciate wear on a modern stylus you must know the original tip profile and be able to measure any wear properly against a known reference image. The best way he suggests is to superimpose images of the worn profile against a new profile, precisely as illustrated in Ray Parkhurst’s image of the N99E tip. For these comparative images, Mr. Parkhurst combined focus stacking with a lighting technique similar to the Shure SEK-2 microscope. Comparative images from a microscope or having a stylus checked by an expert will get that done. As Henriot adds, “We are talking about 10 microns wearing down to ‘what’?” That question of ‘what’ Henriot asserts is something only Expert Stylus, diamond tip manufacturers such as JICO, and a few other real insiders know with precision."
     
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  8. Dreams266

    Dreams266 Forum Resident

    Location:
    NJ
    Its common knowledge that cartridges burn out. I also hear people saying theirs do not. I dont know what part(s) are wearing out but they do.
     
  9. Ray Parkhurst

    Ray Parkhurst Well-Known Member

    Location:
    Santa Clara, CA
    Do yours stop functioning completely, or do they just start sounding weird, or?? I've personally never heard of this phenomemon, so I'd love to learn more.
     
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  10. BendBound

    BendBound Forum Resident

    Location:
    Bend, OR
    Agreed. And it does not have to be that way. I may have posted the suggestion earlier in this thread, but it would be great to see someone take this on. Preferably I'd like to see this done by a cartridge manufacturer. But it could be done by a researcher who would publish to AES for example.

    The work would be taking say a $500 turntable and a $3,000 done, all properly set up, both with the same cartridge, same VTF, then every 50 or 100 hours, take off the respective cartridges for evaluation. Get photomacrographs or photomicrographs through the evolution to say 2,000 hours. In effect, reproduce what Harold Weiler did in 1954 but for a modern stylus and kit. At the same time or hour internals, use a recorder to put the cartridge through a set of signals from a test lp to evaluate distortion levels and at what frequencies. All of the hours would be done on cleaned lps, either a vacuum machine or an ultrasonic cleaner.

    To make such a test even more interesting, do this at different VTF (e.g., 1.5 gram versus 2.5 grams) for a cartridge of the same tip shape, and on records only wiped clean, as another important variation. I mean of 20 folks I know locally who love vinyl records, only two have record cleaning machines and I am one of the two.

    I'm not in a position to do this at the moment and I wish that were not the case. Otherwise, I would do this myself. But in truth, it would be best for an audio engineer to conduct such a test or one of the cartridge manufacturers. I think if a qualified lab did this, there would be less dispute over the results. Whereas if I did it or someone without "proper" credentials, a group would see flaws in the results, the technique, you have it.

    I highly doubt anyone would take the time to perform such a detailed analysis. Daunting. But unless something like this is performed, we will never truly know what, how, why and when.
     
    Last edited: Jul 12, 2019 at 12:47 AM
  11. Optimize

    Optimize Forum Resident

    Location:
    EU
    Maybe it is adding to the confusion.
    But the discussion about stylus wear and time. Is when playing dry records.

    I was amazed yesterday that there is special equipments for wetting/playing records.
    https://www.svalander.se/shoppen/tillbehoer-till-skivspelare/vaat-avspelning

    It apparently was more common to play wet records in the past. Even Thoréns has recommendations in their user manuals how to set antiscating due to the less friction:

    [​IMG]

    That alone should give longer stylus life and lower wear. And it also rises the questions about lubricants. Like gruv glide and such products.

    But we have a hard time to get to a consensus of a time span for dry playing. So I will regard dry record playback as worse case scenario regarding wear.
     
  12. Leonthepro

    Leonthepro Skeptically Optimistic Autodidact Debater

    Location:
    Uppsala Sweden
    Never heard it either. Do tell. The only possibility I can think of is the rubber suspension stiffening.
     
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  13. Leonthepro

    Leonthepro Skeptically Optimistic Autodidact Debater

    Location:
    Uppsala Sweden
    The numbers are whats of interest not the drawings. Any contact point is only a single point. Although you should say its 2.
    When you show evidence for even advanced styli only having small contact area in the beginning Ill believe it.
     
  14. Leonthepro

    Leonthepro Skeptically Optimistic Autodidact Debater

    Location:
    Uppsala Sweden
    Do you have the Shure study on hand?
     
  15. Dreams266

    Dreams266 Forum Resident

    Location:
    NJ
    Like I said, common knowledge that cartridges degrade. You can research it. The answers are there. I knew the answers in past but have forgotten. If your intent is to deny that cartridges break down i have no interest in arguing this reality with you.
     
  16. Optimize

    Optimize Forum Resident

    Location:
    EU
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  17. missan

    missan Forum Resident

    Location:
    Stockholm
    The problems lie in the presumed indentations under different velocities during play. What indentations should we really believe happen?
     
  18. Leonthepro

    Leonthepro Skeptically Optimistic Autodidact Debater

    Location:
    Uppsala Sweden
    Theres nothing to argue if you have no evidence.
     
  19. Leonthepro

    Leonthepro Skeptically Optimistic Autodidact Debater

    Location:
    Uppsala Sweden
    How do you mean?
     
  20. missan

    missan Forum Resident

    Location:
    Stockholm
    I mean what is in contact with the vinyl surface depends on the diamond´s indentation in the vinyl. I don´t think this is perfectly clear.
     
  21. Leonthepro

    Leonthepro Skeptically Optimistic Autodidact Debater

    Location:
    Uppsala Sweden
    Partly I suppose, but groove walls are formed just like the cutter heads, meaning mostly straight like a triangle. The whole point of finer styli is to imitate this shape and thin ness to maximize surface area for reduced wear and more accurate playback. Some indentation might help, especially for the other simpler styli, but according to the numbers it seems a new stylus already takes up most of the space the groove walls has to offer which is again what its supposed to do.
     
  22. Ray Parkhurst

    Ray Parkhurst Well-Known Member

    Location:
    Santa Clara, CA
    Although you should have convinced yourself with your own pics, here are a couple of simple pics to explain the concept. Curves only contact flat surfaces in a single point. It doesn't matter if the radius of the curve is 18um or 75um, this is just simple geometry. Once some wear occurs on the curved surface, then and only then will it contact as a line.

    [​IMG]

    The vinyl surface will indent due to high pressure on the contact point, and part of the curve will sink into it, thus creating a sort of "line", hence the "line contact" designation. But the forces along that line vary from zero at the edges to maximum in the middle. Once the high points of the curve wear a little, the forces reduce at the center and equalize along the length of the contact, thus approaching what I believe you are thinking is the situation with a new stylus.
     
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  23. BendBound

    BendBound Forum Resident

    Location:
    Bend, OR
    Assuming we are talking about the same reference, see above, I reposted the link, but the link is also in the Finish Line article, in the section that discusses Shure research.
     
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  24. Leonthepro

    Leonthepro Skeptically Optimistic Autodidact Debater

    Location:
    Uppsala Sweden
    This is from a horizontal view, I specified that I was talking about a vertical one.
     
  25. Robert Goodison

    Robert Goodison Well-Known Member

    Location:
    Suffolk, England.

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