JICO rates stylus wear

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JICO rates stylus wear

Post by desktop » 29 Jan 2011 03:57

I've been having a bit of back-and-forth with the designers at JICO. They are certain from their tests that they can see wear on stylus tips (which is the point where there would be audible problems), after as little as 177 hours of use. I'll get more details from a friend soon.

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Post by Whitneyville » 29 Jan 2011 04:18

I'm not so sure of that. They are probably looking at SEM photomicrographs at 4000X or much more, say 40,000X. The "wear" would be "just visible" but depending on the stylus shape and the number of gravity waves around you, I doubt that it's audible for much longer. It's like anyone who has seen a used (but perfect) camshaft from an engine. A brand new cam's lobe's and bearing surfaces are dull. An even slightly used cam, all the surfaces are beyond "mirror polished". And the used cam ( if it was made properly) has more hours of life in it than a brand new cam does. It "work-hardens" and is stronger than a new cam. I have to wonder about the cleanliness of the LP's they tested with also, having used the original stylus for my AT-14Sa for 25+ years with an average of 4 hours a day usage. The SEM 16,000X pix I "conned" showed some wear, but that wasn't the reason I replaced it. The cantilever suspension had gotten quite hard and on my Quad LP's, it didn't sound "right" on them. Normal stereo LP's still sounded good.

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Post by dlaloum » 29 Jan 2011 14:09

There has been some discussion about stylus wear, and it seems that a stylus and suspension initially "wears in".... and (assuming good alignment) improves...

then has an extended period of top level performance before the wear becomes enough to cause performance degradation...

The other thing I've read, is that although line contact styli (Shibata, FineLine, Hypereliptical, etc...) have reduced wear due to increased contact patch, and therefore reduced vinyl/styus pressure per surface area... the MicroRidge types (SAS, Shure MicroRidge, FritzGeiger, AT Microline) will last longest, but when they wear out, can do so destructively for vinyl..

The worn stylus can actually end up with sharp cutting edges (the very fine ridge can break when work leaving a sharp edge on the tip) carving the vinyl, whereas less extreme line contact types like Shibata, Hypereliptical, Fineline, tend to wear more graciously, and when worn out tend to have a soft rounded wear edge resulting in reduced performance but no harm to the vinyl.

There is a (extensive) stylus shape thread where much of this is discussed...

Still interested in any info you get from Jico - communication is NOT their forte!

Whitneyville - with your old AT14Sa stylus, did you experiment with Rubber Renew? (Wintergreen Oil)
If the Rubber has not degraded to the point of actually breaking down, this can sometimes restore it.... with the caution that it can also dissolve plastics, (and stylus needle bonding materials!) so needs to be applied very carefully and in very small amounts - someone did post about their success in restoring the suspension of some old styli this way....

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Post by lini » 29 Jan 2011 17:00

desktop: First of all, nice to see you back on the forum, man! But a question on the topic: Would that refer to their standard quality needles or rather their SAS versions - or maybe even both?

Greetings from Munich!

Manfred / lini

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Post by Ton_Bos » 29 Jan 2011 21:38

Whitneyville wrote:having used the original stylus for my AT-14Sa for 25+ years with an average of 4 hours a day usage
Amazing! I have been wondering since I got my first record in 1967 why common wisdom has it that stylus life is on the order of several hundreds to several thousands hours. Vinyl is pretty soft, and diamond the hardest substance on earth, why would the stylus wear at all? But I never dared put it to the test like you have done!

Bebé Tonto

Re: JICO rates stylus wear

Post by Bebé Tonto » 30 Jan 2011 18:50

desktop wrote:I've been having a bit of back-and-forth with the designers at JICO. They are certain from their tests that they can see wear on stylus tips (which is the point where there would be audible problems), after as little as 177 hours of use. I'll get more details from a friend soon.
I doubt it so. Consensus since the 1950s is that diamond needles last from typically from 300 to 1000h (1000h if the records are always clean and the vinyl compound a is good quality one.)

Some users report using the same needle for years and years without problem. Personally, i've yet to wear down a Shibata (or line contact) needle. Then, i am obsessive about cleaning the record every time before playback.

The more sophisticated stylus shapes can last even more due to the much lower pressure involved on the surfaces, i think Ortofon rated the FG stylus at 3000h of use.

Maybe JICO are doing their tests on their lower end styli.

And certainly if you had a very powerful SEM microscope you could "see wear on the stylus tip" after only 1h of playing.

Finally, i've defended JICO over these years, but it is obvious that they would be very happy if you bought 3 needles instead of 1, you know, "buy several of them because they will wear fast." Plus as far as i know, JICO only assembles the needles; it isn't in the business of diamond polishing (that is done by Namiki as far as i know).

Guest

Re: JICO rates stylus wear

Post by Guest » 30 Jan 2011 18:56

desktop wrote:I've been having a bit of back-and-forth with the designers at JICO. They are certain from their tests that they can see wear on stylus tips (which is the point where there would be audible problems), after as little as 177 hours of use. I'll get more details from a friend soon.
Hi desktop. You've no doubt been privvy to a lot of inside analysis of stylus wear. I have half a theory that the contact area is really a region where the actual contact location, at any given moment, resides. But the actual instantaneous contact location is much smaller than the whole 'contact area. Just the exact location moves about with groove modulation and pinch, different record groove 45 deg tolerances, etc. I hope this makes sense.

In which case, the stylus contact area would 'form' to a shape, a sort of compond curve, that is defined by percentage of time at a particular location, and the friction due to initial stylus profile (angle oresented) at that location. But wear would tend to 'normalise' contact area shape, no matter what initial curve it starts with. Not necessarily affecting performance.

If so, one might imagine exotic shapes wearing to the 'norm' contact shape quite quickly, because the initial profile might be exaggereatedly different......again I hope i've explained this ! The 'norm' would almost certainly be flatter (less curved) than the initial profile.

When it's all said and done 'wear' is a relative term. It could mean tiny tiny changes to contact area shape/profile, formation to the natural curve shape, at one extreme............

Would appreciate comments on this notion.

Also most intrigued to hear more about what prompted the Jico dialog.......?

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Post by desktop » 31 Jan 2011 04:17

Obviously no one wants to reveal special information that they (a cartridge/stylus mnfr) has proprietary knowledge about. That being said, JICO, who I respect in the utmost, now lists a 5% distortion vs wear level, where the original stylus was at the less than 3% level to start. The suspensions are the bit of the system that needs the break-in. The stylus itself is what it is from day 1 (or maybe day 2 if there is a poor polish on the diamond).

I can't tell you how gut-wrenching it is for someone with hundreds of phono cartridge styli to find out that there is significant distortion due to styus wear after 600 hours on ANYTHING JICO has tested. They are very up-front about this on their website. They say that their SAS stylus ONLY begins to have this distortion vs wear/time-usage period after 500 hours. It is also true that the extreme styus designs will wear "with-the-disc" for the first 600-800 hours, and then catastrophic vinyl damage begins to appear.

I found this so hard to believe I asked me retipper to probe the JICO people to know what made them rate styli vs distortion this way. I knew I needed to analyze/rate stylus shapes vs wear patterns vs distortion on either channel for each stylus shape. The weird reality is that if there is "more" diamond, this helps this ratio (see above). But since an MR/VdH/ML/etc. stylus wears in a way that causes the entire stylus to keep tracking highs properly as it is being "ground down", the quality of the sound does not change until the diamond is near catastrophic damage to vinyl.

So, by test, JICO has determined that when measuring ANY stylus design, using the highest quality diamonds, the best they have seen is the VdH1 which will only stay below 5% distortion for 800-1000 hours under the absolute "most perfect" operating conditions. The SAS stylus is very good up to 500 hours along with MR, MT, Gyger1, Stereohedron, etc.

There are so many variables involved that if you only listen to Archive DDG discs or only Telefunken discs with the best vinyl lubricants in the vinyl, or only Desmar discs etc. perhaps your vinyl vs diamond styus wear is less. But, by test now, I think JICO is correct in their assessment of stylus wear. By their tests an SAS stylus is "good" for 500 hours in an optimized tonearm/stylus set-up. Line contact and hyperellipticals are not as good. By the time we get to an elliptical stylus they only stay below the distortion test numbers up to about 200 hours. Sphericals are never below 3% distortion due to tracking/stylus-size problems. But at 7KHz sphericals are usable for 133 hours without a distortion measurement larger than 5% at 7KHz.

The majority of the test measurements used by JICO in this broad test were from 5KHz to 22KHz. This range is not only important for imaging, but many instruments require many high freq harmonics to be properly reproduced (cymbals, piano, tubular bells, carillon, glass bells, castanets, harmonics. etc. I thought at first this was a shameless effort by JICO to sell more styli. Obviously JICO wants to sell more styli.

But my retipper also feels that her styli DO wear out much faster (on a distortion basis) than is the current opinion. So maybe she is trying to sell more retipping (except she is booked for 10 years now). So I tried my own tests. While the distortion at 1KHz remains good for thousands of hours, on many types of stylus tip designs, the distortion at 15KHz shows exactly the wear period vs stylus shape that JICO advocates.

We have all felt the "renewal" of fidelity feeling when we put a new cartridge or stylus into our tonearms. It may be more common than we'd like to admit. I am testing some cartridges from buyers who buy 5x of something if they like it. It is fine with them that I wear-out one of their styli using the JICO 5% criteria. Then I set up a new stylus vs the worn stylus (500 hours) with 2 turntables the same, playing the same music/vinyl. I am unhappy to report that the difference is easy to hear after 500 hours with the best styli.

So I think the optimism hoping for the best, combined with unreasonable advertising information, has made the 1500 to 2000 hour "expectation" a part of the current audio vernacular. This is only because the listeners are willing to accept very high levels of distortion at 10KHz and 12KHz etc. But listeners who use electrostatic loudspeakers, and other very high end loudspeakers, can easily hear the distortions I speak of. ALL the other manufacturers information I have had access to is constant that the better stylus designs would have longer hours of use. But this seems to be based on the assumption that the life span of spherical and elliptical styli were in the range of 500 - 750 hours of usage, and this seems to be generally false.

While multi-thousand X images are often used to EXPLAIN why a stylus is producing higher distortion, it is rare for any manufacturer to make a stylus, ... then play the stylus and test it after 100 hours, and also check the stylus profile when those distortion measurements were made, then the same after 150 hours, 200 hours, etc. etc. Then to make 2 or 3 of these stylus profiles, and test them, etc., is unusual. So a large portion of this information is new (being proprietary, it is normally held close to the vest by manufacturers, and usually this type of testing is only done, when the manufacturer is assessing a batch of diamonds - To Buy). So the CBS tests notwithstanding, the reality of the tests doen checking 12KHz or 15KHz distortion vs hours of use, is new.

There are 2 different perspectives on putting these types of wear numbers into a website for a manufacturer. On the one hand, the manufacturer wants to sell more styli (okay ... that's given). But for the more reputable manufacturers, there is an interest in explaining why the high freq distortion performance for their very best cartridge, begins to degrade, well below 750 hours of use. Explaining this reality to users makes the companies doing it, more credible. Credibility sells styli too.

The changes in sound quality over time due to stylus profile wear, is very subtle as time goes by. This means most listeners don't hear it in an obvious sort of way. But what if you have 20 phono cartridges that are used often. So if I have 2 Denon 300s mounted up, and one has 400 hours on it and the other has 50 hours on it, and I compare them? I would normally attribute a difference in the highs to, the difference in assembly line QC because 300 hours shouldn't make a big difference. But it turns out that it really does make a big difference.

I can usually surpass 200 hours of use for a new cartridge within 3 months of mounting a new cartridge. I've put 100 hours on a new MC cartridge I'm testing and that is after 3 weeks of listening. I use chess clocks for time measurement, and that is reasonably accurate. The diamond profile has changed in this time. I am getting a second identical cartridge model to test as well and I will compare their performance. But it looks like the high end has probably degraded after only 100 hours. I'll check the 2 closely, but I am beginning to feel that JICO is correct. There seems to be real losses in high freq information that begins after 300 hours with any stylus profile and it is obvious and easy to measure after 500 hours.

There are allot of factors being tested in this type of situation, and even the cantilever type and exact adherence to the exact manufacturer's specified tracking pressure can influence stylus tip wear. For those of us who don't have clear, extended freq response hearing, some of this is moot. But I'm still passing the 19KHz test on both ears, so for me it it is a meaningful test. I had passed on info about what manufacturers were telling me, for many years. I am unhappy I may have misled people. Tracking pressure that is too low is just as destructive as tracking pressure that is too high. Cleaning a stylus is essential. But the way vinyl was mixed, and the lubricants used in vinyl, may be extremely important. If these test results vs listening evaluations, is reasonable, then 1/2 of the phono cartridges I am now using, are distorted in the highs above 5%. That is not good.

I hope to get more info now that this problem seems obvious. The slow degradation in the highs due to stylus wear isn't bad, but now that it can be measured through testing, it is probably correct. I often wonder why I would ever use cartridge X when I listen to it after it's been used 500-600 hours, when compared to a new, less expensive cartridge I just got for testing/evaluation. This would seem to explain why some cartridges are so great on first listening, but when reviewed after hours of use, they seem lacking. Wear is inevitable. So I shouldn't have been surprised by the JICO testing. But it is disappointing.

Bebé Tonto

Post by Bebé Tonto » 31 Jan 2011 05:17

I think you're going way too fast, desktop.

First, you should request clarification on the "x% distortion" figures and claims. Correct readout of high frequencies depends on the stylus tip "side" ("minor") radius, and the required stylus tip minor radius depends on:

(a) groove radius from spindle center (ex: 10cm)
(b) frequency (ex: 20KHz)
(c) recording level for such frequency (ex: -12dB)

which in turn directly determines the

(d) curvature radius of the groove (ex: 8um)
(e) acceleration experimented by the stylus (ex: 1000g)

So, to correctly trace high frequencies, the minor radius of the stylus (ex: 6uM) should "fit" into the curvature radius of the groove, otherwise "distortion" will appear.

In practice records never go more than 1200g in acceleration numbers, and even this number seems to be way too high according to ld's calculations.

If we assume that stylus wear causes a "rounding off" of the stylus' side radius, so this radius becomes bigger, then we can safely say that additional "distortion" may or may not be produced, depending on factors (a), (b), and (c) on the record.

What does this means? That a "worn" stylus (that is, one in which the actual 'side radius' has "rounded off" to a greater radius) may or may not cause any sonic degradation depending on factors a, b, and c.

Let's put ourselves into the most extreme case:
(a)Radius =7cm
(b)Freq = 20000 Hz
(c)Level = -20dB (relative to 0dB=5.6cm/s @ 1KHz) ... Note that this is actually a loud level!!

then calculations says:

(d) acceleration = 1000g which is probably the highest accel found on a record
(e) groove curvature radius = 10uM and this is where the fun begins. A standard 18uM conical will never trace this (d,e) conditions correctly, and this is something well known. A standard 18uM conical ALWAYS gives a substantial amount of 2nd harmonic distortion when operating under these conditions, new or worn.

Now, a typical shibata stylus has 6uM of side ("minor") radius, and thus it can trace a signal at these (d,e) conditions easily. THEN, of course, as the stylus is worn, the side radius will change until a significant amount of 2nd harmonic distortion will appear. BUT... This distortion will be lower or comparable to the one found when tracing the same signal with a brand new 18uM conical stylus!!

BOTTOM LINE IS... Don't get so scared of those "distortion" (you haven't specified which distortion but i'm assuming 2nd harmonic) numbers, since

(1) conical styli will always introduce a very significant % of 2nd harmonic distortion even when new (numbers available elsewhere in this forum)

and

(2) very fine styli will always have lower distortion numbers than the conical, even if worn.

plus

(3) even a very worn SAS tip (side radius = 2.5uM when new) will probably never get it's radius sufficiently rounded off to seriously "erase" the higher frequencies, even at extreme cases of groove curvature.

To put things into perspective, i have a cartridge intended for CD4 records (required bandwidth = 20 to 50000Hz). The stylus tip (shibata, side radius = 6uM) is rated for 300h, after this amount of time it will not read correctly the 30KHz carrier on a CD4 record... but it WILL read properly any stereo record with fine sound, since the side radius will still be pretty small.

and

(4) the sonic degradation will be of consequence only at the inner grooves and only on certain records (most cutting engineers reduce the HF content at the inner grooves to keep the accelerations low)

Finally, i think it was ld the one who mentioned long ago that some stylus tip profiles "wear" into more benign profiles, and the conical profile was the one that worn down in the worst way.

Bebé Tonto

Post by Bebé Tonto » 31 Jan 2011 05:29

desktop wrote: lists a 5% distortion vs wear level(...)But at 7KHz sphericals are usable for 133 hours without a distortion measurement larger than 5% at 7KHz. (...) from 5KHz to 22KHz (...) the distortion at 15KHz shows exactly the wear period (...) very high levels of distortion at 10KHz and 12KHz (...)checking 12KHz or 15KHz distortion vs hours of use (...)
With my previous post i wanted to tell you that posting frequencies ("15KHz", etc) is meaningless for such tests if you (or JICO) does not specify the radius from the spindle to the groove (a), and recording level (c).

For example 7KHz can be traced even with a huge 70um diamond tip (!) if such signal is at the beginning of the record and the level is -6dB. 7KHz. Big deal.

So JICO should give you the complete set of numbers, otherwise they are meaningless.

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Post by Whitneyville » 31 Jan 2011 05:54

The EPA banned Rubber-Renew several decades ago here. It was also sold as "Dr. Scat" for typewriter rollers, but no more. Even older, back in the 60's when 40's and 50's cars and trucks into the 60's had windshields with natural rubber seals. I've used gallons of the old "Rub-R-Nu" brand "rubber renewer" on windshield gaskets and on wiper blades when I pumped gas for a living. I have a "Field Service Manual" of the B-17G "Flying Fortress" that mentions "Rub-R-Nu" for many of it's window, antenna, and other rubber gaskets. Spearmint oil sold here is really artificial, as you can get "goofy" smoking real spearmint leaves. "Spearmint" plants are really Arrowmint plants. I'm too lazy to look-up the species tonight, but it was on TV on "Oklahoma Gardening" on educational TV this afternoon. Arrowmint is a natural bug repellent, similar to marigolds and pyrethium daisies. None are as effective as some .001% Heptachlor, now banned.

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Post by dlaloum » 31 Jan 2011 06:27

Flavio - The one item you have not tackled clearly is destructive wear....

From what I have read the issue withe the MicroRidge type styli (ie the extreme forms) is that the ridge is so fine that as it wears it can become brittle and a piece can break off - leaving a jagged pointy edge that can cut the vinyl.

So it is not strictly the wear - but the combination of wear and collapse/breaking that can make MR/ML/SAS dangerous.

Whereas the HE, Shibata and other types that have "more" diamond there, sacrifice a little curvature, but tend to wear into a "conical" pattern.... which is non destructive. There is always plenty of diamond mass supporting the structure, so it doesn't break leaving a cutting edge.

After reading about this, I made a decision to focus on slightly less extreme profiles.... such as Shibata and HE.... but I then found that the very best cantilevers are usually mounted with MR styli, and when you go down a notch in styli, you frequently lose the TOTL cantilever..... Frustrating.

Whitneyville - I believe the main ingredient in the Rubber Renew compounds is/was Methyl Salicylate (Wintergreen Oil), and this appears to still be available (eg: http://www.wildroots.com/wintergreen-es ... -1211.html ) Some of the car forums provide details of the blend of ingredients with the Wintergreen oil that can be used to renew auto rubber....

Back to the main topic.... Stylus Wear

Any info out there on the impact of the Last system on stylus wear? (and any associated work on distortion...)

Just got my microscope working yesterday, and went through a batch of suspect styli - to my surprise many of them were only showing a touch of wear.... (or perhaps I just don't know how to spot it yet, nor how to measure the amount of wear...)

Bye for now

David

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Post by zeplin43 » 31 Jan 2011 15:32

Well here goes my 2 cents on my results with stylus wear.
My ears are the only instrument i have to give this Op.
My setup has 2 TT

Technics1210 MkII with the better quality stylus(Denon Dl 160/110/V15 vn35 MR /M97ex)Used mainly with new or Excelente Lps

JVC QL F6 with pioneer PC 220 (AT95 clone)with cheap conical stylus to play used lps.

All Lps have been nicely wet washed.
The speaker system is a JBL 7.1 so pleanty of tweeters to hear the stylus change in sound.
We are heavy vinyl users so 300 hour/month is the estimate playing time.

1 - Conical bonded stylus.
Break in takes about 15/20 hours then it plays used lps with satisfactory results till around 230/250 hours then i start to hear destortion in the sound especially on the inner grooves.this is more evident on the worst lps then it goes on degrading from lp to lp,and i have to change the stylus.This has happened 4 times in the last 5 mounths.
Other conicals used before have hade +- the same performance.

2 - Nude Stylus (DL110 + Dl160)
The Denon DL110 that played all sorts of lps since i only had 1 turntable
Break in is about the same as conical, then it played +- 450 hours with an excelent sound until i started to notice some degrade.
The Dl160 has been used only on new or excelent lps it has been running for +- 650 hours now starting to loose that cristal sound it has and the stylus is now very small when comparing to a new one.

Has been replaced with a used VN35 MR i got from e""y and is sounding excelent after 30 hours.

Bebé Tonto

Post by Bebé Tonto » 31 Jan 2011 16:24

dlaloum wrote:Flavio - The one item you have not tackled clearly is destructive wear....

From what I have read the issue withe the MicroRidge type styli (ie the extreme forms) is that the ridge is so fine that as it wears it can become brittle and a piece can break off - leaving a jagged pointy edge that can cut the vinyl.(...)

Any info out there on the impact of the Last system on stylus wear? (and any associated work on distortion...)
David,

I think you're worrying WAY too much. No one on this forum has reported any kind of record damage by using a MR or ML tip.

As for the "Last" system, search for Whitneyville's posts... If you want to extend your stylus/record life 2X, just play your records wet with distilled water. No need to pay for an overpriced "miracle" record lubricant.

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Post by desktop » 31 Jan 2011 18:59

From what I understand 2nd hand, the NHK test record has 3 bands/groups of frequencies cut at 4 levels (+3bd, 0db, -6db and -10db). I don't know which frequencies they use exactly, but I assume 15KHz is one of them since that is an important broadcast cutoff frequency. There is also a sweep tone in each band. One band is near the outer edge (although having seen one of these discs, it looks like the area of a standard lead in groove is blank, then there are discreet frequencies cut followed by a sweep tone). Then there is an obvious blank/uncut area about 2 cm wide then a middle area with the same frequencies cut, then another blank space, and then an inner band/group that is cut, although there is a substantial area uncut/blank in the center group of frequencies, where typical discs have a lead out groove.

I believe JICO is using the middle test bands @ 0db & -6db, because this is the area with the least tonearm error for testing using standard pivoted tonearms. The person visiting JICO thinks their tests measure THD on each channel, using an older piece of B & K equipment like the 1901 which is a comparator style distortion analyzer (if I remember correctly[?] although it's been years since I used this type of device).

But I am also pretty sure that if JICO is only willing to claim that their best stylus profile (the SAS) will only track a 15KHz tone at 0db in the middle of the disc @less than 5% THD up to 500 hours, because they have worn a few of these styli to nubs testing. Destructive use testing is costly, but with a sample of 17 units being used with various tonearms to get a range, and then a few extra tests added when there is an obvious set of results for a certain tonearm falling outside the reasonably expected norms, it would be possible to determine likely thresholds of stylus damage due to vinyl contact. In fact, these oft-cleaned test discs are very well made since they are important to the radio business. Older vinyl of unknown quality could easily produce results that are worse.

As far as anecdotal evidence is concerned, I am prey to the "gradual" deterioration effect, so that small increases in distortion, that build over time, are much less obvious to my ear, than catastrophic damage. So it is easily possible that if I am using a few favorite photo cartridges, cleaning them regularly (and at best checking them with 150x-200x magnification once in a great while), I might not hear the point when the THD on one channel surpasses 5%. But what does happen is that I also like comparing well used and barely used cartridges from the same batch.

That test can be a real eye opener. If I like a cartridge, I have often purchased 2 or 3 extra styli for it. While I can sometimes tell my really fussy-cleaning friends that they might get 1500 or even 2000 hours of reasonable play from their well made, high end profile (SAS type) styli, I also know that they are usually playing undemanding rock and pop music for the most part. My friends who listen mostly to classical music or unprocessed vocal music are quicker to complain about distortion, often becoming unhappy at 500-1000 hours of stylus use.

I find that it is easy to determine which cartridge I am using when comparing between 2 from the same batch, one with 50 hours of use, and one with 300 hours of use, although I've never tested an MR stylus this way. The stylus with 300 hours of use is always obviously poorer in sound quality compared to the newer stylus, with any profile like elliptical, shibata or line contact, or more complex profiles like Stereohedron, ML, VdH, Gyger, Replicant etc. I like shibata styli because they seem to deteriorate sonically at a slower rate, and the distortion products are less "nasty" to my ear. And I've done this same comparison between a new-ish stylus and a 300 hour used stylus for my friends. Most can hear the difference. At 1000 hours, most are so horrified with the sonic output of their styli compared to a new-ish one that they don't want to use the 1000 hr stylus any more.

So distortion "creep" could easily surpass the 5% level of THD at frequencies above 7KHz, and listeners might not perceive this distortion because the onset is so gradual. Remember that loudspeakers (and I have 25 years experience making and testing loudspeakers with the cost-is-no-object assistance of Bruel & Kjaer while I worked at Disney), can have most of their bandpass way above 5% distortion. In fact there may only be a few narrow bandpass regions in most loudspeakers with distortion under 5% distortion. So most listeners will be using a distorted playback device to make their listening determinations. The noise floor in the listening room, and the various standing waves, buzzes from objects in the room etc. also act as masking factors when trying to determine if a phono cartridge stylus has deteriorated substantially. Electrostatic headphone users probably hear comparative degradation distortion most easily.

All things considered I find the conclusions JICO is now "standing by" in print in their website to be very reasonable. There may be other factors involved in the manufacturing process. For example shibata styli are usually polished using direct application of abrasive diamond dusts, while the most complex shapes are all made using lasers to cut the diamonds, because concave shapes are impossible to make through polishing. The way to test this variable is to make a few dozen simpler shaped styli like ellipticals and shibatas using laser cutting, and compare them to ellipticals and shibatas made by direct polishing techniques.

I always had a dozen excuses as to why a stylus with 300 hours use sounded worse than an identical stylus from the same batch. I always thought it was due to "dirt" getting into the surface pores and imperfections of the diamond, or I thought that perhaps the discs I had played using one stylus were dirtier, or more damaged, or had more crushed vinyl in them etc. There were other factors like the number of times a stylus might have been dropped or the tracking pressure difference. And all of these excuses seemed to satisfy me for each case.

I'm very lucky that I have had 3 sets of cartridges I could use for listening tests in multiples. I have 2 Nagaoka NP-50 bodies and 6 styli. I have 12 Stanton 681 bodies from the 70s-80s and probably 20 styli (2xA, 2xE, 10xEE, 2xEEE and 4xS), in fact I might have a few more sitting around I have never opened. I also purchased 4 Denon 300 cartridges. These are all excellent cartridges and the styli are well made. They are all fine for listening. Recently I have begun to accumulate a number of Shure M97 HE, XE and EJ styli for 3 of those cartridges. They are reasonable too. Using a better quality (often calibrated) cartridge/stylus combo gives me a good starting point for comparative testing. But I don't have a lab, or the best test discs. I have 2 Rocks and 2 Luxman PX-101 turntables in identical condition (although the identical-ness factor can be eliminated if tests are run switching cartridges back and forth). But most important, I don't keep a distortion analysis test set, up and running, all the time to check for TDH at 10 hours, 20 hours, etc. up to the hundreds of hours of stylus use level. I also don't have skilled techs, who can use their "off" time when sales are slow, to do all this testing.

This was one of the great things about working for Disney. We never had to guess about whether we were buying the best 12 inch woofer out of 25 possible "good" choices. I just requisitioned time from our techs in our Dept 395, and they just plowed through the repetitive tests until the best one, or two or three woofers became known. Then we moved on to destruct testing on the cream of the crop. I believe JICO has all of the requirements needed to make real determinations about when styli have lost enough of their profile to be causing substantial distortion.

JICO is testing using pure tones. On the one hand this may make certain distortions more obvious, while music may mask some of these distortions for normal listening. But in the real world there is another factor that can create distortions in the sonic recreations. Flavio mentioned the CD-4 demodulation process, and the rating in hours of styli used for CD-4 discs. Since I was in the retail hifi business when this process was developed and marketed, I remember that the records themselves were rated for only 200-300 hours of use before the carrier signal tracks were assumed to be too badly degraded for reasonable playback. This was what the shibata stylus was introduced for. But it was also one of the first times that very high quality discs began to use band limiting when being cut, because if there was 30KHz information cut into the "normal" stereo groove (from piano harmonics for example), it would interfere with the CD-4 demodulation process and so it had to be filtered out. At that point it became obvious that many discs, had allot of sonic information above 20KHz, cut into their grooves.

Spectrum analysis was becoming the hot test when I switched to the audio manufacturing environment in 1976/1977. When discussions came up about tweeters, I loved pulling out discs and playing them to point out how much information many discs contained above 22.5KHz, and how compressed speakers sounded if the speaker had great high frequency extension (perhaps -10db at 30KHz) and a 21KHz filter was cut into and out of the circuit. Today Tannoy makes a nice (moderate size) loudspeaker with flat on-axis response out to 40KHz for studio monitoring of SACD discs. There were 30ips analog tapes made in the 70s and 80s with allot of high frequency info at 30KHz and remastering these tapes requires a playback system better than the tapes.

The discs with allot of +20KHz information often separated the cartridge "men from the boys". The shibata nude diamond improved the sound of those non-CD-4 albums dramatically. But ellipticals, and worn shibatas, could often sound really bad playing some of these ordinary off-the-rack vinyl albums because of the way they turned extreme high frequency information into hash. Often the IM products of this problem hash, interacting with the 20-20KHz program material, made one cartridge stylus sound much better than another. In other words excessive distortion and mistracking at 25KHz, would influence the quality of the sound at 7-15KHz. A worn shibata stylus, unable to properly track a normal 30KHz bit of program could ruin the overall sonic image in the audible range.

The other factor that involves CD-4 reproduction is that even if the carrier frequency was reproduced with 25% distortion (like turning a sine wave into a triangle wave), since the 50 KHz waveform (of any type) was subtracted, leaving only the differential "music" behind, the ability to track at 50KHz allowed for huge amounts of distortion (with even higher than 30KHz or 50KHz frequency distortion products). The rear channel reproduction was also less "important" than the main stereo "front" image, so higher distortion was less audible.

So I like believing the JICO opinion on profile degradation vs THD. They have the ability to manufacture styli. They have techs who can be assigned test work. They have the NHK right there to help them. They have the lab facilities. And they would have the desire to plot graphs showing the amount of degradation vs hours of use that styli would incur.

When I was hired by Disney at the recommendation of Dick Heyser (who preferred keeping his job at JPL), it was like the perfect storm. I was interested in every aspect of design, acoustics and human interaction with audio reproduction through loudspeakers and Disney had the money and the interest to check/test for anything that might influence human decisions about sound at EPCOT, Tokyo Disneyland and EuroDisney. The "turn-off" factor was death to repeat visitors, and bad sounds could be a turn-off. Since those projects were worth about 5 billion dollars in production costs and the monthly profits from those venues could average 150 million dollars (in 1985 dollars), spending 25 million 1981 dollars to know everything possible about loudspeakers was a small price to pay.

JICO can get their investigations much cheaper than Disney. Disney is an entertainment company that needed to buy a lab and hire people. JICO already has the techs, and the lab, and the know-how, and the help of the NHK.

Never underestimate the audiophile market in Japan. There are so many people in Japan with a truly burning desire to hear the best possible sound from vinyl, it would surprise us all. So the motivation to know all there is to know about stylus wear vs distortion exists in Japan, and at JICO. It is like that perfect storm again. The only difference between my Disney loudspeaker experience and the the regimen JICO is now running, is that I had unlimited financing, while JICO just does this as they go along.

JICO makes/polishes conical, elliptical, shibata and hyperelliptical styli, and they also make AT Microline styli and their own SAS styli. I look forward to seeing JICO list all the stylus profiles they make and test, and the average number of hours of use on a given stylus profile before they are over 5% distortion at various frequencies right in the middle of the disc. In the same way that loudspeaker owners were aghast at distortion numbers in the double digits when I tested their favorite loudspeaker at Disney, we should all be prepared for really short lifespans for stylus tips if JICO publishes info about ellipticals etc.

Electrostatic loudspeaker lovers will really appreciate this knowledge, because full range electrostatics are one of the few loudspeakers with less than 5% distortion at average listening levels across most of their usable bandwidth. I use Martin Logan electrostats because they were made 40 miles away from here. I make other loudspeakers I use, but I don't make electrostats, so I buy them. My own speakers have much higher high frequency extension (-3db @50KHz), but the Martin Logans are lower in distortion over the 20-20KHz range. I wonder what experience other electrostat users in our group have had with cartridges and what they can hear of degradation distortion through electrostatic loudspeakers. Do we have users listening primarily on electrostats, and if so, what phono cartridges do they use, and how easily can they tel when a stylus tip is worn too much? Electrostat listeners would be like the canary in the coal mine.

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