Advanced Stylus Shapes: Pics, discussion, patents.

[dlaloum]

You wouldn't perchance have an EPSP205 stylus (worn out) that you want to part with?
I have a stylusless body, and without a stylus, I cannot get it retipped.... very frustrating!

[dutchflea]

No, sorry. Why can't you get a new boron cantilever? Although you won't get the original thing I guess people like vd Hul and SoundSmith should be able to mount something decent on that cart?

I bought the EPC-P205CMK3 new old stock a few years ago and mounted it in a SL-10 which I cleaned and lubricated to perfection, but never got to use it. So the unit is just sitting on a storage shelf with a new cartridge and stylus. I have another SL-10 with a MC310 mounted. I am surprised by how much the popularity of these units has been increasing the last few years.

[dlaloum]

Nice idea, but they need something to mount the stylus in... normally you supply them with the stylus mount - even if the cantilever is broken...

So what I need is a spare stylus mount - then I can send it to VdH or SS (or expert, etc..)

[St.Dunstan]

Many thanks for all, who make this very informative topic, especially for the papers from the initiators of the patents.

[dlaloum]

An addendum...

Using the formula in Walton's late 60's article (Measuring Pickups - in the VE library), I measured the resonant frequency of three Ortofon cartridges, so as to calculate the vinyl groove/stylus compliance constant, to then work backwards to permit calculation of the ETM.

Thread here: viewtopic.php?f=19&t=46785

Given this - it should be apparent that ETM as advertised by the cartridge manufacturers is effectively an alternative restatement of the primary resonance.

If a manufacturer quotes the ETM, we can therefore calculate the primary resonant frequency, and vice versa if they quote the resonant frequency we can calculate the ETM.

What is less clear is whether the "ETM" in fact represents the effective tip mass, rather than being an amalgam of differing factors - effectively a sort of artificial "trackability" factor of sorts.

[Ldg]

For info, here's some of my own high magnification microscopy showing the front on view of some common stylus types, in the location at the extreme tip showing the contact locations.

Ortofon 2M Red, bonded elliptical (bi-radial ?) :



Ortofon 2M Blue, nude true elliptical :



Stanton 500V3, bonded spherical :

[Ldg]

For info, here's one of my markups, showing real front on images of a bi-radial elliptical (left) and FG (right). Note the groove depth scale is somewhat understated, as borrowed from the original, but the contact locations and base clearance should be correct :

[lukpac]

First of all, this is a great thread. Tons of information I haven't seen elsewhere.

However, does anybody know why some stylus shapes have problems with (some?) styrene pressings? My AT440MLa (Microline) will shred Monarch pressed styrene 45s; in addition to permanent distortion (mostly in one channel), shavings can be seen quite clearly coming off of the stylus.

My AT331LP/8008 (Line Contact) does not seem to have the same problem, although it still does leave visible marks if set down between grooves in the lead-in and lead-out areas.

I contacted Audio-Technica about this, and their response was basically "we've heard of these issues, use a different stylus". I have also played a little bit with arm height and anti-skate, but the problem seems relatively constant. And to be clear, I don't have any such issues with vinyl pressings.

As a side note, I have a couple of styli for my AT331LP, and it is interesting how differently they track on some records. It isn't clear to me if perhaps one is damaged or mounted on the cantilever slightly differently or what.

[Ldg]

Hi Lukpac. Although I don't know for sure, I suspect it's associated with stresses associated with reduced minor radius, essentially becoming more blade like. To an extent this seems mitigated by increasing the major radius toward line contact, but this depends on indentation to be effective. See my earlier posts on this thread as to why this might not happen.

If true, it wouldn't surprise me if shredding wasn't vinyl composition sensitive. I attribute similar effects I've encountered on a few older vinyl pressings with an OM40 FG stylus to such things, but again I don't know for sure.

I believe it's why one doesn't generally see higher VTF ranges with line contact stylii. The marketing machine makes a good job of promoting advantages of large major radius (line contact), which are disputable anyway IMO, whilst the issue of downside due to small minor radius are seldom discussed.

I might be wrong, but it's enough to make me cautious about line contact stylii, especially on earlier vinyl pressings. Horses for courses, but I'm preferring sphericals generally these days, when one can find quality examples. And sonically too, esp on older vinyl pressings up to the late 60's.

Just my 2p worth !

[lukpac]

I might be wrong, but it's enough to make me cautious about line contact stylii, especially on earlier vinyl pressings.

Perhaps other people have different experiences, but I've never had an issue with *vinyl*, only styrene.

Horses for courses, but I'm preferring sphericals generally these days, when one can find quality examples. And sonically too, esp on older vinyl pressings up to the late 60's.

While my experiences are arguably fairly limited, I've noticed far more distortion with spherical styli, especially in the tight inner grooves. While the 440 isn't necessarily the best for everything (on some pressings I've noticed a bit more noise than with my 331, for example), I have definitely had better luck with line contact type styli when playing passages often prone to distortion (sibilance in the inner grooves, for example).

[Ldg]

Yes, the occasional shredding experiences I've had with vinyl and an FG stylus are quite rare, and more associated with clogging, with the odd telltale string. I checked carefully for chips too, and I'm pretty certain all is as should be. But it still nags me, hardly surpringly.

I don't note any difference between inner groove/sibilence trackability generally that follows stylus profile, assuming all other things are equal and the stylus of good quality, polish, geometry and shank alignment. It should be generally negligible anyway. Just recently, an astonishingly good tracking cartridge I've had the priviledge to test is equipped with a an 18um spherical, FWIW. But, I'm on a bit of a spherical push these days, see how far it can be taken.

[Hepokatti]

ld, do you have any examples of cartridges having sphericals of good quality? I've heard DL-103 tracking like a beast, is that already an acceptable spherical? My experience with sphericals is from piss poor to poor.

You say that stylus profile doesn't make a noticeable difference when tracking inner grooves/loud passages. I'm actually not that surprised, but sounds interesting nevertheless as I have completely opposite experienes. Then again, I've only seen/heard those cheap sphericals.

Currently my gut feeling about the tracking issue is that a nude high quality (fine line) diamond with a real good cantilever is what gives best performance tracking wise (if we assume mass/compliance matching is perfect).. have I been "off" with my assumptions?

[lukpac]

I don't note any difference between inner groove/sibilence trackability generally that follows stylus profile, assuming all other things are equal and the stylus of good quality, polish, geometry and shank alignment. It should be generally negligible anyway.

Pinch effect is pretty well documented, and the reason elliptical styli were created in the first place. While you may not notice it that much, it is certainly real.

[Hepokatti]

Pinch effect is pretty well documented, and the reason elliptical styli were created in the first place. While you may not notice it that much, it is certainly real.

I want to jump in here and ask if you happen to have a link or something to point me to a direction of such documentation? And I do mean I want to see them, I'm not trying to be rude, simply curious

It was discussed in another topic recently whether ellipticals cut (front/back) from sphericals provide any added benefit, as their groove wall contact area is virtually the same. Front/back cuts do not seem to add to groove wall contact area. They only reduce the diamond mass.

While some pictures, for example in this thread, may suggest that "vertical" tracing is better with ellipticals, the pictures portray unrealistically dense grooves and seem more like marketing material rather than scientific illustrations.