Advanced Stylus Shapes: Pics, discussion, patents.

[chiz]

What do you think about Ortofon Arkiv stylus? Not a hifi but still interesting. It is r/R 13/25 elliptical, major radius bigger than 0.7 mil conical, would it sit higher in the groove?

What headshell does this fit / how is it mounted?

The cartridge was sold in both OM and Concorde versions.
The stylus will fit any standard OM body.

[watchnerd]

I believe due to possibly bigger contact area it would not cause more rapid wear at 3 g VTF than ordinary 0.3x0.7 elliptical at 2 grams.
If Ortofon would make 2-3 gram VTF range 0.6 mil conical for OM/Concorde I would definitely buy one.

I'm curious why archiving would require a stylus any different from a normal hi fi stylus, or perhaps an SPU for old 78s....

[Sunwire]

Can anyone give authoritative dimensions for these Audio Technica advanced stylus shapes?

And which ones are or may be identical to styli used by other manufacturers (Ortofon, etc)

The ones I'm interested in are:

1) Bonded "Linear Contact" as found on the ATN125LC, ATN122LP, ATN3472LC (I think these are all the same, but I could be wrong)

2) Nude-mounted "Linear Contact" as found on the ATN140LC, ATN142LP, ATN155LC, ATN152LP, M14LC (I think these are all the same, but I could be wrong)

The other Audio Technica advanced shapes seem to have been discussed in some detail, but not these two.

Also wondering if anyone has any data or estimates of the masses of these styli compared to Microline, Shibata, or the Special Line Contact diamonds.

My reading makes me think the Microline/SAS is the best stylus available today. How much better is it than the older nude Linear Contact stylus used by Audio Technica?

[patient_ot]

My reading makes me think the Microline/SAS is the best stylus available today. How much better is it than the older nude Linear Contact stylus used by Audio Technica?

Linear Contact, as you know is just a trade name. We'd need more info to figure out what patented shape that really is. In terms of what is available today, the ML is just the trade name for the Namiki Microridge. If you look up info on the MR, including the patent documentation, you will see that the MR has the narrowest side radius of any of the patented shapes. IME it tracks inner grooves better than anything else. The FGs, Oguras, Shibatas, etc. all have larger side radii. AFAIK there has not been a new patent since the late 80s, so anything else not patented is just marketing/trade name.

[chiz]

Nude-mounted "Linear Contact" as found on the ATN140LC

I don't have any contact dimensions but I do have pictures of this one:




Here the shank sizes are given as 0.15mm square for the 140LC and 0.12mm square for the 155LC:

https://www.vinylengine.com/ve_download ... gue_82.pdf

[billshurv]

Good question. My understanding was that the 'LC' stylii were a shibata, but no corroborating evidence. I do know that my one LC has become my second favorite cartridge.

[BlazingArrow74]

I'm definitely no authority on stylus shape, but as I understand it the "Linear Contact" profile describes a broad subset or method of groove scanning: namely, the large major radius. I would guess that although the nude mounted types are sturdier and probably easier to align, the MR, when aligned properly, would yield better sound due to the highly polished minor radius (the "Ridge").

[Sunwire]

Good question. My understanding was that the 'LC' stylii were a shibata, but no corroborating evidence. I do know that my one LC has become my second favorite cartridge.

AT sold Shibata styli during and after their "Linear Contact" styli were on the market, so I imagine there must be some difference.
My nude LC styli are my favorites or tied for favorite status. But that could be due to the beryllium cantilevers they're mounted on.

[patient_ot]

This is pure speculation, but I almost wonder if those older AT LCs are a VDH design. I read an interview where VDH accused Namiki of appropriating his work at one point. One of the VDH designs is spec'd at 3um x 80um.

3um x 80um = .11811 mil x 3.14961 mil

Round that and you've got a .12 radius.

Some of the current ML/MR styli also have a .12 radius. ML/MR is obviously a bit different than VDH though.

Just an idea.

[Sunwire]

Here the shank sizes are given as 0.15mm square for the 140LC and 0.12mm square for the 155LC:

https://www.vinylengine.com/ve_download ... gue_82.pdf

Thanks for that link, chiz.

The brochure says:
The 155LC stylus is a "modified Shibata stylus precision-ground to a linear contact tip shape".
The 140LC stylus is a "linear contact stylus resulting from further refinement of the Shibata stylus"

I remember reading (maybe in this thread) that the Shibata stylus has a curved contact patch. So maybe the AT stylus is a modification to remove that curvature. (?)
None of the drawings showing Shibata contact patches seem to show this curvature, however.

I also noted that the top cartridge described in that AT brochure is the AT1000 (MC), which has an "ultra-low mass (0.006 mg) 0.06 mm square shank natural diamond ground to an elliptical cross section and nude-mounted to a natural diamond, taper-cut cantilever. Moving mass is extremely low, and signal transfer speed is higher than that of any cartridge manufactured today."

Perhaps it's logical to assume the 155LC stylus weighs around four times as much as the AT1000 stylus, or around 0.024 mg. But we don't know how long these diamonds are, do we?

[ray_parkhurst]

I remember reading (maybe in this thread) that the Shibata stylus has a curved contact patch. So maybe the AT stylus is a modification to remove that curvature. (?)
None of the drawings showing Shibata contact patches seem to show this curvature, however.

All new styli have curved contacts (large radius). This allows some initial wiggle room for misalignment. During break-in, wear flattens the contact surfaces, making them more "linear" and orthogonal.

[billshurv]

The shibata is actually curved in 2D. If you go back to page 1 of this thread you can see that.

The confusion comes when you look at the attached and then compare it to the very similar one on page1 of the thread. There appear to be two definitions of Shibata. One is 6x75um and the other is 6x45um. Line contact is 6x75um. At a guess at some point 'small' shibata was defined as shibata and 'large' shibata was defined as 'line contact'.

I'm sure this was all discussed at length back in 2009 and the same lack of conclusions reached :)

[chiz]

There appear to be two definitions of Shibata. One is 6x75um and the other is 6x45um. Line contact is 6x75um. At a guess at some point 'small' shibata was defined as shibata and 'large' shibata was defined as 'line contact'.

On this page Namiki have data for "Line Contact" (6 x 75 μm) and "Type III" (5~8 x 35~45 μm)
From the accompanying drawings these do both appear to be variants of the original Shibata design:

https://www.ad-na.com/en/product/jewel/ ... tylus.html

In the 2014 AT catalogue there are both "Line Contact" and "Special Line Contact" models with a spec of 40 x 7 μm which matches the Namiki Type III:

https://www.vinylengine.com/ve_download ... 014_en.pdf

Also, from page 33:
“Audio-Technica uses Line Contact shape stylus on several high end cartridge styli. The tip of the diamond is such that it allows a contact surface between 50 and 75 μm2. The shape is “similar” to other diamond tips known as Shibata.”

Nothing here to suggest that the 1980s LC were the same spec as the 2014 ones though.

[billshurv]

Does seem so. I'm only really worried about the 80s spec ones mind :)

Of course the reality is that once you get above 40um R it doesn't matter so much as you have most of the line contact goodness. But would be nice to know.