This is the same argument / explanation that appeared in the audiophile press of the mid 50s when stereo and right before Hi-Fi records made their debut. After he expenditure of much ink and paper it was the opinion of the majority that the reproducer tip should follow the same line as the recording cutter with the minimum force required to maintain grove contact. There were several different terms for the geometry of the reproducer travel however to add to the general confusion. And, yes Virginia, the elliptical contact diamond styli does cause measurable wear in a vinyl recording grove. The diamond also shows visible wear over time. Much less per play than the machining operation that takes place between a steel needle and shellac record. The bottom line is that tone arm geometry of a classic acoustic phonograph designed for lateral cut records is horrid. I would play nothing on one of these machines that was either valuable or that I wanted to keep. The only good news is that a big stack of well played 78s and a case of shotgun shells can keep a couple of young boys entertained for an entire Saturday afternoon. Greg Bogantz wrote: > Well, Robert, you make some good points in this discussion. But you > are in error on some as well. First, what you term "azimuth" error is > more commonly called "lateral tracking angle error" or LTA by the > tonearm engineers. It was widely discussed and debated, particularly at > the dawn of the stereo LP with many learned papers written about it in > the audio engineering press. This tracking error became more of an > issue with stereo records because it is associated with a slight phase > misalignment of the two walls of the groove (thus the two stereo > signals) as the cartridge tangency changes. (This is a separate issue > from vertical tracking angle error VTA which was also an issue with > stereo records but has no significance to lateral monophonic > recordings.) The result of a lot of "sturm und drang" over LTA error > was that, yes, it exists, and yes, it can be reduced to a minimum with > the choice of the proper offset angle of the head of the tonearm as a > function of the distance of the tonearm pivot to the platter spindle. > You are correct that the shorter this arm pivot to spindle distance, the > more the LTA error. You are also correct that this error results in the > steel needle turning with respect to groove tangency as the record is > played from one diameter to another. It is reasonable to assume at > first blush that this turning will present a sharp edge of the > previously flatted side of the needle to the groove wall and thereby do > some gouging of the wall. However, you are forgetting that the groove > is not without wiggles in it which represent the audio modulation. > Which means that the groove wall is continuously changing in its > instantaneous tangency with the needle. This means that the needle does > not have purely FLAT spots worn on its sides, but rather slightly curved > (convex) spots as the sharp edges are continuously worn down by the > modulation in the groove. The higher the modulation, the more this > curvature will present. Therefore, the additional slight turning of the > needle in its tangency with the groove caused by LTA error is probably > insignificant in its effect on groove wear as the needle doesn't present > but statistically a very tiny amount of additional rotation beyond the > curvature of the flats caused by the previous record modulation. In > other words, the effect of LTA on causing additional record wear is > probably negligible. The effect might be more noticeable on records > with very low modulation such as some classical chamber music or similar. > > Your statement that vinyl record cannot and do not wear diamond styli > is not correct. I was engaged in doing a lot of record compound wear > testing when I worked at the RCA Records manufacturing labs in > Indianapolis. We were developing two radically new record compound > formulations at the time. One was needed for the new CD-4 quadraphonic > audio records which contained supersonic signals up to 45kHz and the > other was needed for the RCA Capacitance Electronic Disc (CED) video > disc system that was still in development (it was vertical modulation, > you might be interested to learn). Consequently, we had installed a > scanning electron microscope (SEM) to evaluate the effects of wear both > on styli and on records. The SEM allows remarkably detailed views of > the minutest surface irregularities with extremely high magnification > and extremely long depth of field view (sharp focus over a wide range of > depth in the specimen) that is not possible with optical microscopes. I > did wear testing of the audio record formulations using several stylus > shapes and tracking forces that represented the typical users of the > day, about 1975. We checked the amount of wear that could be seen at > intervals of 25 plays from 0 to 200 plays using players operating > typical high quality stereo cartridges operating elliptical diamond > styli at 2 grams, Shibata diamond styli (line contact) operating at 2 > grams, and conical diamond styli operating at 5 grams which represented > a good consumer type player of the day. The results were frightening! > The typical stereo vinyl record compound exhibited quite noticeable > "trenching" of the sidewalls of the groove with the 5 gram conical in as > little as 25 plays. When auditioned, especially after 50 plays, these > records sounded well worn with much noise and crackling. The 2 gram > elliptical fared better, but at 100 plays it produced noticeable > trenching as well. The Shibata at 2 grams would show very little wear > of the sidewalls at 200 plays. > > What's more pertinent to this discussion, however, is that the styli > had to be changed at regular intervals as they ALSO exhibited noticeable > flattening of their contact surfaces. I could get upwards of about 1000 > plays from the 5 gram conical diamonds before I decided that they had > gotten too flatted. And, as I have stated above, the "flats" weren't > actually flat but rather broadly convex flatted portions at the contact > points. 2000 to 3000 plays were about where I changed the 2 gram > ellipticals, and the Shibatas could last for 5000 plays or more. And > these vinyl record formulations contained no abrasives. But they DID > wear the styli. > > Lastly, I think you need to take another look at the LTA issue with > the Edison DD player. Yes, the Edison tonearm is pivoted in front of > the pickup as opposed to being pivoted at the back as with all > conventional lateral players. But it is still a pivoted tonearm and it > DOES exhibit LTA error. It just occurs with the reversed tangency arc to > that of the back-pivoted arm. In the typical DD player, the LTA is > fairly low at the outside record diameter but becomes quite high at the > inside music ending diameter. In fact, the LTA error was deliberately > used to advantage in the development of the Duncan electric stop. The > fact that the LTA is very high at the inner diameter of the DD player > causes the stylus to skate toward the spindle with considerable force. > When the stylus falls out of the groove at the inside end of play, the > stylus and weight assembly swing inward until the weight limit pin hits > the limit loop which makes the electrical contact that the Duncan stop > relies on to close the circuit and operate the solenoid which stops the > DD motor. If there were no or very little LTA error, the skating force > would be minimal and the weight would not swing to the edge of the limit > loop. > > Of interest here is that this LTA error on the DD player is basically > irrelevant, assuming the stylus is in good condition. The Edison as > well as the Pathe system relies on the conically shaped stylus tip > sitting directly on the bottom of the groove to properly trace the > vertical modulation. It can do this properly REGARDLESS of the tangency > of the pickup head to the groove. You will note that some record > players designed to play both vertical and lateral discs with their > adjustable reproducers often present the Pathe stylus to the record > groove at quite a radical angle to the tangent. The Brunswick Ultona > comes to mind. Yet the system works because the LTA is irrelevant for > purely vertical modulation. Also note that Pathe tonearms are often > quite short. But the LTA that this causes poses no problem to the > reproduction. > > Back to the case of record wear: The Edison DDs were specifically > designed to have quite a hard surface compared with the shellac material > that was used in lateral records of the day. That's why Edison chose > the condensite material. The playback theory of the lateral records was > to have the abrasive in the record material (which by the way was not > diamond dust which was much too expensive - the abrasive was a > combination of the cheap clay filler and pulverized limestone) wear the > needle rapidly so that the "flats" developed which VASTLY increased the > contact surface area and thereby quickly reduced the pressure on the > sidewalls which reduced further record wear. If you were to play a > shellac record with a new steel needle every few turns of the record > (quite a tedious operation), you would find the record very quickly > wearing out because you would not be allowing the use of a properly worn > in steel needle with the right size flats. You may have noticed that > some records sound particularly noisy during the first few revolutions > of the starting grooves. This is because the use of a new steel needle > causes excessive wear in this portion of the record. > > Contrary to this theory of operation, Edison wanted to wear the > diamond stylus rather than the record surface. So he used a stylus > shape that had a fairly big radius, AND which sat on the groove bottom > with a large percentage of its circumference supported by the matching > radius in the groove. This spread out the high tracking force over a > fairly large contact patch at all times. There was no need to wear > flats on the stylus. Note that even if the point of tangency changes > due to the LTA error of the Edison tonearm, the spherical stylus tip > merely rotates in the groove but STILL presents the same curved contact > surface with the record which does not have any additional effect on > record wear. The choice of the condensite material was such that it's > elastic yield point (permanent deformation) was higher than the pressure > presented to it by the rounded stylus sitting in the rounded groove. > All is well and good until the stylus becomes chipped. When this > happens, the sharp edge of the chipped area presents a much smaller > contact patch to the groove which very quickly yields the condensite > under this very high localized pressure and results in a very visible > brownish-looking scratched appearance. The record surface has now been > permanently damaged and the record will play that area with much > increased noise. Regardless of whether you call it wear or damage, it's > been ruined. > > Greg Bogantz > > > > > ----- Original Message ----- From: "Robert Wright" <esroberto at hotmail.com> > To: "Antique Phonograph List" <phono-l at oldcrank.org> > Sent: Thursday, March 06, 2008 2:19 PM > Subject: Re: [Phono-L] Shellac records and damage from steel needles > > >> "I don't think anyone ever said that no wear (not damage-the choice >> of terms >> shows a prejudice) to a record occurs." >> >> Au contraire, dear Ron, it is eBay seller "nickjay" (or that's what he >> used to go by) who has said in no uncertain terms that he believes >> ZERO damage (or wear) happens with a single playback with a new steel >> needle. So yes, I'm afraid someone has said it, and I'm sure he's not >> the only "true believer" out there, as Rich pointed out. >> >> I'm suprised by the strongly defensive stance you take on behalf of >> steel needles, though I know you must have your reasons. But no >> amount of positive semantics replacing my negatively prejudiced choice >> of terms is going to reduce the amount of shellac dust I find all over >> the tip of every brand new soft-tone steel needle I play a shellac >> record with, so the terms really don't make any difference in the real >> world. >> >> I absolutely agree that optimal set-up on any machine reduces wear to >> a minimum (that's most of what the set-up is for, as minimum wear >> often equals optimum sound), but I was pointing out the one aspect of >> pivoted playback that the purveyors of this myth seem to be either >> ignorant or unaware: that azimuth error reduces the "new needles wear >> down to precisely match the groove and cause little to no wear after >> the first few grooves" theory to bunk. >> >> I also agree some machines had better designs than others. I know a >> lot of earlier, outside-horn machines had tonearms that were pretty >> darn long; every millimeter of added distance between the pivot point >> and the needle tip helps correct the azimuth error by some degree. I >> don't know how much heavier or lighter these older machines register >> at the needle tip, but I'd be willing to bet records suffered less >> wear played on them with new needles than on newer, shorter-tonearm'd >> models. (Unless, of course, there was very little compliance at the >> needle shank pivot on the older machines... I wouldn't know, I've >> never messed with any of them.) >> >> What I don't agree with is there being some great difference between >> wear and damage -- wear IS damage as far as I'm concerned, whether >> expected or not. Frankly, who among us makes such a distinction when >> considering buying a record that we later find out has almost >> completely greyed-out grooves? Who among us minds the occasional edge >> chip or flake? I fully expect those with shellac discs, as a part of >> "normal use" involves handling, and normal handling includes the >> occasional, accidental chipping of a record edge. No, I say it's a >> matter of simple semantics, none of which make any real difference -- >> but by all means, use whatever terms suit you, as will I. >> >> Lastly, a bit of quick clarification: regarding Edison DD's and the >> reasons for their relative lack of wear through playing, Pathe discs, >> unlike Edison DD's, are made of the same stuff as lateral shellac >> discs (minus the diamond dust, I'm assuming), and the only Pathe's I >> find with groove damage have obviously been played on a lateral >> machine with a steel needle at least once (it's a very obvious "look" >> the surface has when subjected to such numbskullery). As I said, >> Pathe's sapphire ball stylus machines offered exactly the same tip >> profile to the groove regardless of position and/or angle of the >> soundbox, because it was spherical; as such, I've never seen a clean >> vertical Pathe disc in the middle -- it has either been shredded to >> nothing by misuse, or its playing surface looks -- and sounds -- >> pristine. >> >> Final point (so to speak, ha ha): you won't get me to believe that >> the world's hardest substance can be altered by one of the world's >> most pliant. Modern cartridges are not "retipped" because of wear to >> the diamond; the entire cantilever is replaced, along with the >> cantilever's suspension. When burning in a new stylus, it is this >> cantilever suspension that is being broken in, and when the stylus >> needs replacing, it is because of the cantilever suspension, which >> cannot support the recommended Vertical Tracking Force after so many >> hours of use, making the magnets attached to the cantilever become >> misaligned with the coils inside the cartridge. Plastic does not wear >> down a diamond. (Playing shellac discs with diamond dust in them is, >> however, another story completely, as a diamond will obviously be >> reshaped by grinding against diamond dust -- that's how jewelers >> shape them to begin with.) >> >> Don't let wear OR damage stop you from playing your records, but do >> know what you're signing up for and act accordingly. >> >> Best as always, >> Robert >> >> >> ----- Original Message ----- From: "Ron L" <lherault at bu.edu> >> To: "'Antique Phonograph List'" <phono-l at oldcrank.org> >> Sent: Thursday, March 06, 2008 9:01 AM >> Subject: RE: [Phono-L] Shellac records and damage from steel needles >> >> >>> I don't think anyone ever said that no wear (not damage-the choice >>> of terms >>> shows a prejudice) to a record occurs. That is clearly wrong for the >>> reasons you have stated. Wear to the needle continues throughout the >>> play >>> of the record. If a machine is properly maintained and the >>> reproducer has >>> compliant parts, when a new steel needle(not a nail - see comment in >>> parentheses above) is used, wear is kept to a minimum. Having said that, >>> further qualification should be made. Some machines had better >>> designs than >>> others. Steel needles are ground to a point and tumbled to create a >>> particular radius on the tip they are not merely, "headless nails." What >>> has happened over time is that the whole playback system has become >>> refined. >>> Even diamond styli are worn by vinyl records and the records >>> themselves are >>> worn (degraded) every time they are played. No contact system of >>> playback >>> will eliminate this. If you have a super-valuable/rare record, >>> should you >>> play it repeatedly with a steel needle? No. But then again, you >>> probably >>> shouldn't play it repeatedly with any needle/stylus. >>> >>> I think Greg Boganz mentioned the lack of wear on DDs on the >>> Electrola list >>> recently. It is not entirely because of the tone arm and has to do with >>> vertical grooves and the nature of the DD surface. >>> >>> Ron L >> >> _______________________________________________ >> Phono-L mailing list >> http://phono-l.oldcrank.org > > _______________________________________________ > Phono-L mailing list > http://phono-l.oldcrank.org > >