JICO rates stylus wear

the thin end of the wedge
dlaloum
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Post by dlaloum » 31 Jul 2011 07:10

Yes CL & My discussion got a bit heated - best to move it back to this thread!

Going back to the side topic under discussion a couple of months back (Jico stylus information)

I have found that there is a touch more information available.... but one needs to look at the Jico Japan website (with the assistance of Google Chrome auto translate...)

For each stylus they also list the recommended VTF.

In a number of cases, apparently similar styli (Empire 2000, 2000/I, 2000/II, 2000/III) have differing VTF - implying differing compliance - as per the originals.

I think part of the problem is that Jico are not an incredibly good company at marketing themselves!

Has anyone managed to get good pictures of wear levels at differing playing hours? (or know of published information on this?)

bye for now
David

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Post by cafe latte » 31 Jul 2011 07:26

Good question David. I know that how clean the records are, condition, and downforce are all factors, but some good pics would be great..Precious vinyl is at stake!! :D
CL

dlaloum
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Post by dlaloum » 31 Jul 2011 07:37

I would happily endeavour regular pics of my styli at known intervals, but my scope really isn't up to it!

An Aldi Traveller USB scope - with no proper mechanical stage and max resolution of 200x - just won't cut the mustard! (with time and effort I can inspect a stylus for wear - but getting consistent measurable results, where the stylus patch width could be measured is far out of its capabilities)

I keep an eye out every so often for a used scientific scope.... but they usually go for more than I am willing to spend on curiosity!

bye for now

David

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Post by Guest » 31 Jul 2011 08:57

dlaloum wrote:Has anyone managed to get good pictures of wear levels at differing playing hours? (or know of published information on this?)
Other than the pics in the manual of Shure's inspection microscope, which appear extreme IMO, no.

I've never been able to see the so called 'flats' myself, and I've never seen a picture of normal wear at the point one might decide there's excessive distortion.

What's more, i'm not convinced normal wear pattern should be flat (unless one listens to silent grooves !), but rather a region of decreased curvature. And therefore hard to spot ('scuse pun!).

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Post by missan » 31 Jul 2011 13:08

If we imagine that these flat spots are true, when in the stylus life do the they start to appear? Do they appear from the very start, but very small and slowly getting larger, or do they appear in the end of stylus life, and start rapidly to increase, depending on some mechanism, like pinch effect or something?

All seem very unclear to me.
missan

dlaloum
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Post by dlaloum » 31 Jul 2011 15:05

I've definitely seen the flat patches - or at least their reflections under the microscope - pretty much as described in the Shure scope manual.

And usually asymmetrical - one side worse than the other (on styli I've received with used cartridges)

Question is - what does an additional 1% distortion look like?
2%?
4%?

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Post by Guest » 31 Jul 2011 15:29

Not when you think about the surfaces from which the light is reflecting. IF there were flats that reflect side on light so as to appear as two spots, so would a curved surface reflect as two spots at the same location ! There will always be an alignment that reflects as tiny spots, even on a curved surface.

More to point ('scuse pun!) spacing isn't right.

Show me the evidence !

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Post by dlaloum » 31 Jul 2011 15:47

The twin spot reflection requires two lights at 45 degrees out to the side respectively (90 degrees between the two lights, obviously)

So the incoming light is same as the groove angles...

But on my scope it is achieved with a hand held LED light, which I shift around to get first the left side, and then switch hands and do it on the right side.

I can usually light up the "spot" for a conical/eliptical for LC's it can be tricky as the line that you can get reflecting extends far past the actual groove contact area...

When they are in good nick it is hard to differentiate... when they are worn, you sort of see the line reflecting and (when the angle of the light/stylus is just right) you see it bloom out into a "patch"

Here is a TK9e stylus with one side worn...

First the worn side
18362

then the less worn side
18363

It takes patience to get these shots !

With a proper Shure scope it should be a lot quicker!

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Post by Guest » 31 Jul 2011 16:11

Yes, those reflections from side light will happen whether the surface is curved or flat. They'll happen when the side spot light exactly matches the surface angle in 3D to reflect exactly upwards. Glint.

When I've done the same thing, I've found that carefully rotating the stylus on a stage, whilst observing the glint, implies a uniformly curved surface. I've not been able to find flats that stand scrutiny, even on stylii i consider to sound worn.

The acid test is that location of the 'spots' has correct seperation to be contact points, and whether they are of credible size. I reckon those photos are curved surface glint, not wear spots, DL.

One can use cantilever diameter as calibration.

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Post by Doug G. » 31 Jul 2011 20:58

The magnification of those photos is nowhere near high enough to actually see the wear facets.

You need to have more like 200X magnification. Those are only about 50 - 75X.

Go to the sticky thread on Audio Karma called Sparky's Fabulous Stylus Microscope or something like that in the turntables forum.

It's been a while since I've looked at it but I believe there are some representative photos in there of what magnification is needed to actually see stylus wear that means anything.

Doug

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Post by Bebé Tonto » 31 Jul 2011 21:44

I think i have only worn 1 stylus in my whole life and it was a Stanton D89AL conical. I also have a Shibata that might be slightly worn but i have to do some tests.

But i have damaged a lot of styli by mishandling...

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Post by Guest » 31 Jul 2011 22:12

Doug G. wrote:Go to the sticky thread on Audio Karma called Sparky's Fabulous Stylus Microscope or something like that in the turntables forum
Thanks, and I think it serves to illustrate the issue of interpretation here. Some posts there acknowledge that glint happens even on curved surfaces. And actually, some of the images said to have 'severe wear' are looking at reflections from the front/back intentional flat grinds of an eliptical :roll: . Quite a few have the 'flat spots' 90 deg out !

For context of where the contact locations are, here's an SEM image of a sperical in a groove :

http://www.sciencephoto.com/media/215066/enlarge

Assuming that image is stereo 12.5um spherical, top groove width is nominally 50um.

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Post by cafe latte » 01 Aug 2011 00:11

Ok guys, how many hours do you think stylus last?
CL

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Post by cafe latte » 01 Aug 2011 00:16

ld wrote:
Doug G. wrote:Go to the sticky thread on Audio Karma called Sparky's Fabulous Stylus Microscope or something like that in the turntables forum
Thanks, and I think it serves to illustrate the issue of interpretation here. Some posts there acknowledge that glint happens even on curved surfaces. And actually, some of the images said to have 'severe wear' are looking at reflections from the front/back intentional flat grinds of an eliptical :roll: . Quite a few have the 'flat spots' 90 deg out !

For context of where the contact locations are, here's an SEM image of a sperical in a groove :

http://www.sciencephoto.com/media/215066/enlarge

Assuming that image is stereo 12.5um spherical, top groove width is nominally 50um.
Interesting shot ld. That would IMO make Davids spots too low down the diamond as we would expect to see any spots almost at the tip, but on the sides.
CL

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Post by Bebé Tonto » 01 Aug 2011 05:44

cafe latte wrote:Ok guys, how many hours do you think stylus last?
CL
"Long enough" hrs + "long enough" minutes.