Best stylus shape for playback of acetates?

[Steve E.]

I don't know why this has never occurred to me before.

In general, when playing back an acetate, is there a preferred stylus shape? I'm wondering if conical styli are better. I could imagine that an elliptical stylus might be more likely to shred or cut the soft material. Certainly, some people recommend against using elliptical styli for records pressed into styrene (like 45 singles) for just this reason.

Any thoughts?

[maniman]

Ohhh. interesting , an eliptical stylus not necessarily be more sharpened than an conical stylus , [not ? ,]
in that way a conical stylus is most desireable for me when testing cuts , if not jumps with the conical less with an eliptical , [not ?]
in the other way , a eliptical stylus have better tracking , that can means less weight for a good tracking than with the conical ,
and in that way maybe can be less aggressive with that soft material than a conical , [not ? ,]
only fast lucubration really not use a lot of acetates.

Best Regards and many many thanks to mantain all this Steve.

[pentlandsound]

I'm a comparative newcomer to record-cutting, following the 'Peter King' tradition of embossing on to polycarbonate using a sharpened steel stylus. The records I end up with play fine using a properly calibrated arm with counterweight, and an elliptical stylus (eg OM-10).

I recently acquired one of the recent 'Sound Burger'-style copies - an Ion LP-2-GO - on which none of my home-made discs would play at all. The stylus simply jumped straight across the record to the centre pin. This particular turntable does not seem to have any means of calibrating the arm or adjusting tracking weight etc, and the arm itself shows a hefty bias towards the centre. Nevertheless, commercial pressings play fine on it, as do Peter King's own lathe-cuts and those from PIAPTK.

The stylus on the LP-2-GO is conical, which I think may have been part of the problem - the other being that my home-made grooves weren't deep enough to prevent such a stylus from jumping out. After a great many tests I've finally got my cuts to track OK on the LP-2-GO, by making some changes to my lathe set-up. For what it's worth, these are:

Stylus point: sharpened to 70° - 75°
Stylus rake: trailing 20° - 30°
(If trigonometry serves, this should yield a groove profile somewhere around 90°)
Embossing head weight: increased to 120 grams. (I think Peter King uses 150g, but my Lenco is struggling as it is)

The only problem I have now is a long-standing occasional squeak from the indenting point. I'm still not sure what is causing this! Maybe a heat-lamp might help?

Thanks all

David
13.12.2012

[Steve E.]

bump. I'm still interested in this question, and I'm surprised it doesn't come up more. Is there any data on conical vs elliptical playback of acetate discs and the wear they put on the soft records?

[Greg Reierson]

I remember reading about it in the AES Anthology. Elliptical does more damage to the lacquer but I don't remember the specific recommendation for what does the least amount of damage. I'll take a peak when I get back to the shop.

[concretecowboy71]

What is the intended purpose of the playback stated in the original post?

Dub plates being played in a club or checking test cuts for tracking issues?

I use a wide variety of playback options here to look for tracking issues and I don't care if the test cut get ruined by the stylus.

We have had a number of times over the last few years where a client says a record skips on their system and we cannot get it to do the same here. I have always wondered if it was a difference in stylus that might have been the issue.

Here is a thread with audiophiles discussing their opinions.

http://www.audiokarma.org/forums/archive/index.php/t-169146.html

[Serif]

There are all sorts of opinions on and conditions for what shape stylus makes a record sound good, but sphericals are said to wear out the grooves faster since they don't follow the chisel shaped groove as closely as the elliptical and shibata or nude/fine-line tips do, thereby skidding over tight curves and presenting more drag profile to the material. However, for back-cueing and scratching techniques used by DJ's, in practice the spherical tip is less damaging (during those activities). Counter-intuitive? Do you want to scratch and back cue your dub plates? A heavy elliptical is probably more harmful than a featherweight spherical, but these are the exceptions which only prove the sort of rule.

There's a YouTube of Bob Ludwig explaining how he lost the grandmothering job for Led Zep II because although it was louder than the other examples offered and played perfectly on his reference tt, his cut skipped while played in Ahmet Ertegun's daughter's record player (Close and Pray?). He says at the end that the moral is, when someone asks for a hotter record, give it to them. Of course, this is _NOT_ the answer he's actually presenting, since he lost the job, and it's true that most players out there are not well set up pickups. I don't know what shaped jewel the daughter of Atlantic records founder was using on Ludwigs cut or even if it was a lacquer or pressing, but I guess it was spherical and that the tracking force was excessive and that there was no anti-skate counter-weight applied to the tone arm.

If you want to know what the real world is like and how adequately the grooves will play there, have a relatively heavy tracking 2,5g? spherical (of 0,6 or 0,7 mil radius) tip. My 6g Voice of Music has been banned from playing microgrooves and I call him, the Mangler.

If you want to know how good your acetate can sound, however, and to make them last for future plays back, first try it using an elliptical or fine line stylus with no more than 1,2 g tracking force and with all calibration aspects, from spindle overhang to anti-skate (to avoid right-channel distortion, as explained in the AES paper written by George Alexandrovich, Sr.), stylus centerline-to-arm pivot vertical tracking angle around 15˙, and stylus centerline scanning rake angle orthogonality sorted.



- Serif

[boogievan]

Decent troll thread... Saw this pic over at vinylengine and hope they won't mind my referencing their link. It says it shows on the left the elliptical groove straddle while on the right, the Bang & Olufson Pramanik, named after the inventor of the first tangential arm player Beogram 4000 (not sure about this claim, but he did good). The Pramanik and Beogram were used with 4 channel, but I don't know if it was CD-4 or some other flavor. Pramanik styli are meant to be cut nearly the same as Serif's shibatabata bing bang mentionangg. "She bought a what?" Seriously, the Pramanik looks like a Micropoint®.

conical-eliptical-stylus.jpg

- boogie

[dubcutter89]

There was a paper by J.G.Woodward , M.D.Coutts , E.R.Levin of RCA Labs published by AES
where they use a SEM (scanning electron microscope) to analyse records, needles etc. The paper dates 1968

One of the tests was to look at silent grooves (cut in a lacquer) played back with a sphreical / elliptical stylus 1 or 10 times:
(.7mil radius spherical / .2 x .7 mil elliptical)

"The bearing weight was 2g in each case. A small amount of wear is identifiable after 10 passes with the spherical tip.
With the elliptical tip, wear is discernible after one pass and is conspicuous after 10 passes. It is interesting to note that
most of the wear from the elliptical stylus is near the bottom of the groove."

So i guess a good quality MM-Cartridge with low mechanical impedance and spherical tip is a good starting point...

Lukas

[Greg Reierson]

"The bearing weight was 2g in each case. A small amount of wear is identifiable after 10 passes with the spherical tip.
With the elliptical tip, wear is discernible after one pass and is conspicuous after 10 passes. It is interesting to note that
most of the wear from the elliptical stylus is near the bottom of the groove."

Yes, that's what I was referring to above. Thanks!

[opcode66]

We have had a number of times over the last few years where a client says a record skips on their system and we cannot get it to do the same here. I have always wondered if it was a difference in stylus that might have been the issue.

I'm guessing your clients don't have the proper tracking force set on their tonearm for the cartridge they are using... That is usually why something skips on the other end. The tonearm is set way too light.

[jjgolden]

Yep,
Also mal-adjusted anti skate.

[EmAtChapterV]

For what it's worth, I recently cut a locked groove of a 1 kHz tone at +4 dB, and used it to break in a new elliptical stylus (Ortofon 2M Red). I left it running for five hours, so the same groove on the acetate was played 10,000 times. After it was over, the stylus had a little beard of acetate material, and the split-second point where the groove overlapped sounded fuzzy, but the rest of the groove was surprisingly distortion-free, and still looked shiny and well-defined under a microscope.

I should try this again with actual musical material and see what sort of results I get. I do however note that backcueing an acetate with any elliptical stylus has always meant instant cue burn. Forwards only!

[jjgolden]

Thats good info to know. Was there a level drop afterwards?
If you try it with a 10k tone i bet the results will be very different though. (not at +4 of course...)

[Serif]

Hi,
The elliptical and the spherical tip are not being tested equivalently if their tracking forces are identical (as they are in the Woodward, Coutts, Levin test). The psi is greater with the smaller footprint, so the way to compare the two requires different respective tracking forces for the stylus shapes tested. Not to quibble with RCA labs, but just as there are many AES paper authors who contradict each other, I object to their test method and defer to the papers of Bastiaan and Pramanik who recommend an elliptical tracking force of ideally no more than 1,25g. I suspect that the deformation of the groove bottom is not linear with change in tracking force, but possibly is arithmetic, if not exponential. I like the Scanning Electron pictures, but there should be no elliptical stylus used at a tracking force as high as 2 grams on even vinyl. I use mine at ~1,25 g. The spherical causes less wear at the tracking force used in their test, but it also will have more tracing distortion and a featherweight stylus of even fine-line cut will be much less damaging to lacquer or vinyl than to drag through them any 2 gram jewel. Vinyl deforms at 3g. Furthermore, the jewel tip which is small enough in radius to follow the treble when at the lightest tracking force will be less prone to bang hard into curves, as it will more easily obey the S turns, whereas the spherical is pinched and, in the process, does blur the walls, deburring and lapping.

I'd like to see the scanning electron pictures when the spherical is at a more typically used and more equivalent tracking force of closer to ~3g and the elliptical is dragged through the multiple passes at the more typically fine-tuned and equivalent weight of something less than ~1.5 g.

- Serif

[boogievan]

...you had me at "...electron microscope." The topic reminds me of the difference between tape machine designs - pinch roller but with all rolling guides (guess) or pinch roller-less transpo but with some fixed and some rolling guides. How slowly the tape can be shuttled ends up being the decisive factor in which is gentlest, since it's almost a toss up given that there are so many unshared compromises between the two designs. Similarly, the spherical's tracing distortion can be dealt with using the tracing simulator pre-distorter during the cut, but its efficacy wanes considerably the more refined and Pramanik-like the pickup stylus used on the pre-distorted groove. Better to use no predistortion if the likely playback pickup is fine-line. And no one using spherical expects top sound, does he? Ergo - try one of each for testing, but the lightest touch seems plausible as the better friend to lacquer...




- Tim E.

[Angus McCarthy]

*pic*

Ah, great reference shot. It makes me glad I invested in a 3 mil conical pickup for my standard groove discs!

[THD]

Was it styluses Neil Young was thinking about when he sang: "The Needle And The Damage Done"?

Anyway, here are three cool pages for people who like record players:


http://www.turntablebasics.com/cartridges.html

http://www.ortofon.com/images/stories/stylus/Everything%20you%20need%20to%20know%20about%20cartridges_Stylus%20type.pdf

http://www.vinylengine.com/examining-your-stylus.shtml

[gold]

Hi,
The elliptical and the spherical tip are not being tested equivalently if their tracking forces are identical (as they are in the Woodward, Coutts, Levin test). The psi is greater with the smaller footprint, so the way to compare the two requires different respective tracking forces for the stylus shapes tested.

I'd think that the mass spring characteristics of the cantilever would have a great influence over the appropriate tracking force. I guess you'd have to define whether the object of the test is to find the best tracking force for a comparison with a spherical stylus or the appropriate tracking force for best performance. I bet that you can't reduce the argument to best stylus shape for all cases. I'm guessing it's more of a case by case basis.

Too light a tracking force can destroy the lacquer just as easily. Too heavy a tone arm can be bad for tracking if there is significant vertical modulation. Helps lateral, hurts vertical.

[boogievan]

]I'd think that the mass spring characteristics of the cantilever would have a great influence over the appropriate tracking force.

Indeed. However, the AES literature already states that 1,25 grams is the ideal for the elliptical. To mate such a jewel to a cartridge with spring characteristics that are inappropriate is obviously ill advised. To use such a jewel at more than ~1,5 g is always unwise. The test is a fail.

I guess you'd have to define whether the object of the test is to find the best tracking force for a comparison with a spherical stylus or the appropriate tracking force for best performance.

You'd first have to limit the elliptical tracking gram-force per square inch to that which is sensible for such a small footprint and then have to increase the tracking gram-force per square inch of the conical stylus by a commensurate amount. That conical spreads its weight across more area, so it cheats by only looking heavy. Only then will the stylus shape comparison test be scientific and will address the OP's as well as Woodward's own test on lacquer wear. Indeed, they ran a parlor trick to make ellipticals look bad. Trolls for truth!

I bet that you can't reduce the argument to best stylus shape for all cases. I'm guessing it's more of a case by case basis.

...indeed, the best shape for a pre-distorted record is that which the record was pre-distorted to undistort - this is only the spherical, so far, afaik. But no one interested in pulling all the available good (hi fi) sound from a disc reaches for a conical if he can reach for an elliptical or smaller. The only issue remaining is how not to over-weigh a jewel with such a small area of coverage (albeit a much better fit against the walls), since it puts all the weight on a svelter point.

Too light a tracking force can destroy the lacquer just as easily. Too heavy a tone arm can be bad for tracking if there is significant vertical modulation. Helps lateral, hurts vertical.

Too heavy a tone arm might help lateral tracking to some degree, but it also increases inertia which can cause lifts and skating during heavy modulation of either type (L/L or L/V). If the tracking gram-force is heavy enough to track, it's probably not too light. ymmv



- boogie