Subject: [teres] RAHE cartridge alignment VTA files Date: Thu, 17 Aug 2000 07:42:11 -0700 From: Steve Zettel, Steve Zettel To: teres@aiko.com This stuff was posted to rec.audio.high-end. I don't note any copyrights, and it was posted to a public forum and can be retrieved by any member of the public using the directions at the end of the digest, so I assume this is public domain information. No intent to misuse the information herein (and other legal mumbo-jumbo). Better to beg for forgiveness than ask for permission. . . Steve Z near Libby, MT USA From: owner-rahe-digest@graphics.cornell.edu (Rec.Audio.High-End Digest) To: rahe-digest@graphics.cornell.edu Subject: Rec.Audio.High-End Digest -- Cartridge VTA (Special Edition) Reply-To: rahe-usenet@graphics.cornell.edu Sender: owner-rahe-digest@graphics.cornell.edu Errors-To: owner-rahe-digest@graphics.cornell.edu Precedence: bulk Rec.Audio.High-End Digest Friday, July 24 1998 Cartridge VTA In this issue: VTA observations and questions Re: VTA observations and questions Re: VTA observations and questions Re: VTA observations and questions Re: VTA observations and questions Re: VTA observations and questions Re: VTA observations and questions Re: VTA observations and questions Re: VTA observations and questions Re: VTA observations and questions Re: VTA observations and questions Re: VTA observations and questions Re: VTA observations and questions VTA Tips and Discoveries Re: VTA Tips and Discoveries Re: VTA Tips and Discoveries Re: VTA Tips and Discoveries Re: VTA Tips and Discoveries Re: VTA Tips and Discoveries ---------------------------------------------------------------------- From: "Michael R. Clements" Subject: VTA observations and questions Date: 9 Jul 1998 18:57:16 GMT Message-ID: <6o33qc$dpl$1@agate.berkeley.edu> On a previous thread we had discussed different ideas regarding cartridge alignment. The results as I understand them are summed in the following paragraph: The cartridge should be tangent to the record at every point. But it can't be because the arm rotates around the tonearm pivot. So you can get a maximum of two points along the path it tracks, where it's perfectly tangent. These are called NULL points. Normally, you'd choose a point near the innermost groove, and a point near the outermost groove. Distortion is higher near the innermost groove because (a) the record is moving slower across the needle and (b) the tracking error increases rapidly as you move inward from the innermost NULL point. If you a single point alignment, with the NULL point chosen near the innermost groove, you'll get less distortion past that point, but more distortion near the outermost groove, when compared with a two-point alignment. Given this I bought the MoFi GeoDisc and the DB gauge from the Needle Doctor. The DB gauge enabled me to align the thing *extremely* accurately, much more so than the GeoDisc. Also, the GeoDisk is a single-point guide, where the DB is a dual-point guide. My preference was for the DB gauge (BTW I'll sell my brand new Geodisc cheap to anyone who wants it, just drop me an email). Now I've been messing around with VTA. My cartridge (and most other cartridges) calls for 20 degrees. First, I wonder whether this applies to the cartridge body, or to the needle? I'm assuming the cartridge body, because as far as I can tell it's impossible to measure the angle at which the needle is tracking the groove, but it's quite easy to measure the angle of the cartridge body. I made some big cardboard cutouts at 10, 15, 20 and 25 degrees and held them up against the cartridge while it was down on a record of average thickness. First thing I discovered is that 20 degrees is a LOT of VTA. Starting from zero, more VTA gives more precise spatial placement and an overall tighter, more controlled and detailed sound. Basically, increasing VTA from 0 takes the sound from "fuzzy" to "soft" to "precise" to "hard". Then at a certain point it starts to sound hard and strident. The goal is to find the sweet spot. On my setup, this is around 10 degrees -- measuring from the cartridge body. The latest issue of Primyl Vinyl has an article talking about the Rega 300 and mentions VTA. The author talks of having the cartridge body parallel to the record for testing -- which is a VTA of zero. Do I completely misunderstand VTA, or is this way outside the specification for the cartridge? If this is a case of somebody setting the cartridge way outside the specification range because he *liked* it that way, then I understand. But it makes me wonder whether the manufacturers's recommended VTA refers to the angle of the *needle*, not the cartridge, and perhaps they design the cartridge so that when it's parallel to the record the VTA of the *needle* is correct? My goal is to set up the alignment to the manufacturer's specification, then tweak it around from there to get the sound I like. So the basic question is, "Do you set the cartridge *body* at the VTA angle, or do you set the cartridge *body* parallel to the record, assuming the VTA applies to the *needle* ? ------------------------------ From: Curtis Leeds Subject: Re: VTA observations and questions Date: 9 Jul 1998 19:49:19 GMT Message-ID: <6o36rv$ghr$1@agate.berkeley.edu> References: <6o33qc$dpl$1@agate.berkeley.edu> It's time for another episode of "Reasons To Despise Vinyl, #12 & 35". Michael R. Clements wrote: > On a previous thread we had discussed different ideas regarding > cartridge alignment. The results as I understand them are summed in > the following paragraph:... > Distortion is higher near the innermost groove > because (a) the record is moving slower across the needle and (b) the > tracking error increases rapidly as you move inward from the innermost > NULL point. The former more than the latter; it's the change (decrease) in velocity that tends to add distortion to the inner grooves. However, fine-line styli can minimize this factor to a considerable degree. >...The DB gauge enabled me to align the thing *extremely* > accurately, much more so than the GeoDisc... > Now I've been messing around with VTA. My cartridge (and most other > cartridges) calls for 20 degrees. First, I wonder whether this applies > to the cartridge body, or to the needle? I'm assuming the cartridge > body, because as far as I can tell it's impossible to measure the > angle at which the needle is tracking the groove, but it's quite easy > to measure the angle of the cartridge body. No, you're confused here. VTA (vertical tracking angle) is "the angle between the surface of the record and the line described by the contact point of the stylus and the pivot point of the cantilever". (Credit to Jon Risch, who stated it as simply as possible but not simpler.) There is also - as Risch observed - the matter of SRA (stylus rake angle), and this is an important factor in cartridge alignment, especially with fine-line styli. And since the cantilever is responsible for the angle, VTF effects VTA/SRA. Are we having fun yet? > The latest issue of Primyl Vinyl has an article talking about the Rega > 300 and mentions VTA. The author talks of having the cartridge body > parallel to the record for testing -- which is a VTA of zero. Do I > completely misunderstand VTA, or is this way outside the specification > for the cartridge? You completely misunderstand. > My goal is to set up the alignment to the manufacturer's > specification, then tweak it around from there to get the sound I > like. > > So the basic question is, "Do you set the cartridge *body* at the > VTA angle... Well, here's another wrinkle to consider: many cartridges have slightly imperfect alignment between cartridge body and cantilever so - if you rely on the cartridge body alone for alignment - you'll be misaligned. That's why the best gauges rely on a mirrored surface for alignment. I r-e-a-l-l-y like the WallyTraktor that I reviewed in the latest issue of Ultimate Audio. The CartAlign is also good. The best single reference on this stuff is Risch & Maier, Audio, March 1981. - - *************************************************** cleeds@idt.net "I stood unwound beneath the skies And clouds unbound by laws. The cryin' rain like a trumpet sang And asked for no applause." (Bob Dylan) *************************************************** ------------------------------ From: "Michael R. Clements" Subject: Re: VTA observations and questions Date: 9 Jul 1998 20:39:23 GMT Message-ID: <6o39pr$osd@news01.aud.alcatel.com> References: <6o33qc$dpl$1@agate.berkeley.edu> <6o36rv$ghr$1@agate.berkeley.edu> Curtis Leeds wrote: > No, you're confused here. VTA (vertical tracking angle) is > "the angle between the surface of the record and the line > described by the contact point of the stylus and the pivot > point of the cantilever". (Credit to Jon Risch, who stated > it as simply as possible but not simpler.) > There is also - as Risch observed - the matter of SRA > (stylus rake angle), and this is an important factor in > cartridge alignment, especially with fine-line styli. > And since the cantilever is responsible for the angle, VTF > effects VTA/SRA. Are we having fun yet? > Well, here's another wrinkle to consider: many cartridges > have slightly imperfect alignment between cartridge body and > cantilever so - if you rely on the cartridge body alone for > alignment - you'll be misaligned. That's why the best gauges > rely on a mirrored surface for alignment. I r-e-a-l-l-y like > the WallyTraktor that I reviewed in the latest issue of > Ultimate Audio. The CartAlign is also good. Hmmm. . . So it's totally impossible to know what the actual VTA *is*, because the pivot point is inside the cartridge body, and hence, invisible. So the obvious question is, how do we go forward from here? Do the cartridge manufacturers generally expect owners to set up the VTA so the cartridge body is roughly parallel to the surface of the record? I'm wondering because if I set my cartridge body parallel to the record, the sound is warmer and more lush, but the bass is a bit loose. If I take the cartridge body to 10 degrees VTA, the bass is tighter but the sound is bit bright and strident. ------------------------------ From: johno@vcd.hp.com (John Ongtooguk) Subject: Re: VTA observations and questions Date: 9 Jul 1998 21:04:27 GMT Message-ID: <6o3b8r$kaa$1@agate.berkeley.edu> References: <6o33qc$dpl$1@agate.berkeley.edu> Michael R. Clements (mrc01@flash.net) wrote: : So the basic question is, "Do you set the cartridge *body* at the VTA : angle, or do you set the cartridge *body* parallel to the record, : assuming the VTA applies to the *needle* ? The VTA applies to the stylus, and the cartridge body parallel is a good place to start unless you've been informed otherwise. John Ongtooguk (johno@vcd.hp.com) ------------------------------ From: "Michael R. Clements" Subject: Re: VTA observations and questions Date: 9 Jul 1998 21:48:13 GMT Message-ID: <6o3dqt$mjo$1@agate.berkeley.edu> References: <6o33qc$dpl$1@agate.berkeley.edu> <6o36rv$ghr$1@agate.berkeley.edu> <6o39pr$osd@news01.aud.alcatel.com> <6o3cat$q9i@news01.aud.alcatel.com> Curtis Leeds wrote: > >...If I take the cartridge body to 10 degrees VTA, the bass is > > tighter but the sound is bit bright and strident. > That's a pretty low VTA, unless you actually mean that you > have the cartridge body at 10 degrees to the LP surface, Yes, that's what I mean. > in which case you have a very, very high VTA. If this works best for > you, it might indicate a badly misaligned cartridge. It doesn't work best. It sounds bright and strident. But it does have better bass definition than being parallel. I haven't tried the old (cartridge body parallel) method since I put my turntable on the sandbox. It could well be the increased bass definition came from moving my TT to my new sandbox, rather than the greatly exaggerated VTA. Thanks for the advice; I will try the cartridge body parallel method again. . . ------------------------------ From: Curtis Leeds Subject: Re: VTA observations and questions Date: 9 Jul 1998 21:22:36 GMT Message-ID: <6o3cat$q9i@news01.aud.alcatel.com> References: <6o33qc$dpl$1@agate.berkeley.edu> <6o36rv$ghr$1@agate.berkeley.edu> <6o39pr$osd@news01.aud.alcatel.com> Michael R. Clements wrote: > So it's totally impossible to know what the actual VTA *is*, because > the pivot point is inside the cartridge body, and hence, invisible. You can can quite close, because even a bad guess on the pivot point won't change the resulting angle by much. Some users (I think it was John Elison who suggested this) make little paper cutouts representing the angle they need, and then hold it close to the cartridge during set-up. > Do the cartridge manufacturers generally expect owners to set up the > VTA so the cartridge body is roughly parallel to the surface of the > record? Usually, yes. But some cartridges prefer slight deviation. >...If I take the cartridge body to 10 degrees VTA, the bass is > tighter but the sound is bit bright and strident. That's a pretty low VTA, unless you actually mean that you have the cartridge body at 10 degrees to the LP surface, in which case you have a very, very high VTA. If this works best for you, it might indicate a badly misaligned cartridge. Remember, too: when you change the VTA, you alter the overhang. - - *************************************************** cleeds@idt.net "I stood unwound beneath the skies And clouds unbound by laws. The cryin' rain like a trumpet sang And asked for no applause." (Bob Dylan) *************************************************** ------------------------------ From: Thorsten@tnt-audio.com Subject: Re: VTA observations and questions Date: 10 Jul 1998 16:34:55 GMT Message-ID: <6o5frf$df7$1@agate.berkeley.edu> References: <6o33qc$dpl$1@agate.berkeley.edu> <6o36rv$ghr$1@agate.berkeley.edu> <6o39pr$osd@news01.aud.alcatel.com> <6o3cat$q9i@news01.aud.alcatel.com> <6o3dqt$mjo$1@agate.berkeley.edu> Hi Folks, > > >...If I take the cartridge body to 10 degrees VTA, the bass is > > > tighter but the sound is bit bright and strident. > > That's a pretty low VTA, unless you actually mean that you > > have the cartridge body at 10 degrees to the LP surface, > Yes, that's what I mean. Having the Cartidge Body at 10 Degree and the Cantilever at a nominal 20 Degrees gives together 30 Dgrees VTA. I'd say this is definitly too high. > It doesn't work best. It sounds bright and strident. But it does have > better bass definition than being parallel. Try something more middeling. The best way is to first get used to the sound of the Cart with the Cartridge body parallel to the Record, then move the Arm up somewhat and listen and then again move the Arm below parallel and listen again. You will then have some handle on the Direction you want to move things. The next step is to start moving from the Arm/Cartridgebody parallel to the record-surface in small increments into the Direction you determined before. continue moving the Arm Up/Down untill the sound does no longer improve. BTW, Cartridges having a line-stylus are much more sensible to VTA Changes than those with elliptical Stylii. To my ears the Line-Stylii when set up correctly sound a lot better though.... You might have to re-align the Cartridge, it also pay's to play with the Tracking force and Anti-skating.... All these settings are somewhat slightly interactive in their sonic effects. Allways start however with manufacturers default settings.... Cartridge Loading is another issue. I have found in a few instances that the Manufacturers recomendation will not give the best results. I'm currently running a Cartridge with a recommended loading of 100 Ohm and less than 500pF Capacitance with 10 Ohm and 22nF as Load.... Of course after changing the loading one needs to re-examine VTF and VTA. I end up doing at lest three loops around thsi untill I get the best from a Cartridge.... BTW, what Cart, Arm and Table do you use? Kind regards Thorsten. ====================================== e-mail: Thorsten@tnt-audio.com Visit TNT-Audio on the Web - the only advertising free audio web-zine. http://www.tnt-audio.com ====================================== - ----== Posted via Deja News, The Leader in Internet Discussion ==----- http://www.dejanews.com/rg_mkgrp.xp Create Your Own Free Member Forum ------------------------------ From: sduraybito@aol.com (SDuraybito) Subject: Re: VTA observations and questions Date: 10 Jul 1998 16:46:17 GMT Message-ID: <6o5ggp$dmj$1@agate.berkeley.edu> References: <6o39pr$osd@news01.aud.alcatel.com> "Michael R. Clements" writes: >So it's totally impossible to know what the actual VTA *is*, because >the pivot point is inside the cartridge body, and hence, invisible. > >So the obvious question is, how do we go forward from here? > >Do the cartridge manufacturers generally expect owners to set up the >VTA so the cartridge body is roughly parallel to the surface of the >record? > >I'm wondering because if I set my cartridge body parallel to the >record, the sound is warmer and more lush, but the bass is a bit >loose. If I take the cartridge body to 10 degrees VTA, the bass is >tighter but the sound is bit bright and strident. I think you've answered the question. It doesn't really matter what angle the cartridge body is at. What matters is you achieve the best balance between bass and treble for your ears and you can only get there by listening. Siegfried - - Solid-state = spin-fishing -- - - Tubes = fly-fishing! -- ------------------------------ From: "Michael R. Clements" Subject: Re: VTA observations and questions Date: 10 Jul 1998 18:25:03 GMT Message-ID: <6o5m9v$fc@news01.aud.alcatel.com> References: <6o33qc$dpl$1@agate.berkeley.edu> <6o36rv$ghr$1@agate.berkeley.edu> <6o39pr$osd@news01.aud.alcatel.com> <6o3cat$q9i@news01.aud.alcatel.com> <6o3dqt$mjo$1@agate.berkeley.edu> <6o5frf$df7$1@agate.berkeley.edu> Thorsten@tnt-audio.com wrote: > Try something more middeling. The best way is to first get used to the > sound of the Cart with the Cartridge body parallel to the Record, then > move the Arm up somewhat and listen and then again move the Arm below > parallel and listen again. You will then have some handle on the > Direction you want to move things. I moved the turntable to the sandbox at the same time I increased the cartridge *body* VTA from 5 to 10 degrees. The overall effect was that the sound became bright and hard (bad) but with better bass definition (good). I hope the greater bass definition came from the sandbox and the bright, hard sound came from the 30 degree VTA. If so I should have some pretty good sound this weekend when I take the cartridge *body* back down somewhere between 0 and 5 degrees VTA. > BTW, Cartridges having a line-stylus are much more sensible to VTA > Changes than those with elliptical Stylii. To my ears the Line-Stylii > when set up correctly sound a lot better though.... This is an Ortofon MC-10 Super Mk 2, a low (0.2 mV) output MC. It has a "Fritz Geiger Type II nude" stylus, whatever that is. . . Sounds pretty good to me, though. To my ears, it beats the pants of the Sumiko BPS and it's also more transparent and compelling sounding than the Ortofon X5-MC. I'm using it on a Thorens TD-318 Mk2 turntable with the Thorens arm on a 100 lb. vibration isolation sandbox I built myself and described in an earlier post. I used to listen to high output MCs and this cartridge was an experiment. It's the first low output MC I have used. The experiment was successful because this one sounds clearly better than any other cartridge I've used. > You might have to re-align the Cartridge, it also pay's to play with > the Tracking force and Anti-skating.... > All these settings are somewhat slightly interactive in their sonic > effects. Agreed. It's currently aligned according to the DB dual point gauge. Tracking force seems optimal at 2.0 grams. > Cartridge Loading is another issue. I have found in a few instances > that the Manufacturers recomendation will not give the best > results. I'm currently running a Cartridge with a recommended loading > of 100 Ohm and less than 500pF Capacitance with 10 Ohm and 22nF as First rule of engineering says, "If it ain't broke, don't fix it" and I don't intend to mess around with the loading. Besides, my preamp (a Rotel RC-990 BX) doesn't have adjustable loading. It's set to 47 kOhm on MM and 100 Ohm on MC. This is a pretty minimalist preamp, just a volume control and function selector. Inside, it's also a very clean, minimalist design. I certainly don't want to add new components into the signal path, especially when the sound I'm getting now is so good. Thanks for the good advice. I'll post again next week when I have some results. ------------------------------ From: "Jon M. Risch" Subject: Re: VTA observations and questions Date: 13 Jul 1998 16:46:27 GMT Message-ID: <6oddl3$grj@news01.aud.alcatel.com> References: <6o33qc$dpl$1@agate.berkeley.edu> Michael R. Clements wrote: > Now I've been messing around with VTA. My cartridge (and most other > cartridges) calls for 20 degrees. First, I wonder whether this applies > to the cartridge body, or to the needle? I'm assuming the cartridge > body, because as far as I can tell it's impossible to measure the > angle at which the needle is tracking the groove, but it's quite easy > to measure the angle of the cartridge body. snip > If this is a case of somebody setting the cartridge way outside the > specification range because he *liked* it that way, then I > understand. But it makes me wonder whether the manufacturers's > recommended VTA refers to the angle of the *needle*, not the > cartridge, and perhaps they design the cartridge so that when it's > parallel to the record the VTA of the *needle* is correct? This is what is usually done. > So the basic question is, "Do you set the cartridge *body* at the VTA > angle, or do you set the cartridge *body* parallel to the record, > assuming the VTA applies to the *needle* ? Based on my own research into VTA vs. SRA, it is imperative that the SRA be set to a good angle, virtully i\gnoring the actual VTA of the setup. This is becasue the fine-line stylii require the proper orientation with respect to the angle of the modulated grooves in order to retrieve maximum information, and minimize tracing distortion. If the SRA is off, it is like the head of a tape machine being skewed from proper alignment, the highs are not read fully, and what is read is distorted. With a diamond stylus and vinykl groove, it is much worse, in that there are mechanical interface problems involved, and the stylus is being torqued and grabbed funny by any mis-alignment, causing a lot more distortion than with a tape machine. When the SRA is set too high (the cartridge angled tipped forward), it tends to sound bright and fatiguing, with it set too low (cartridge angled tipped back) it tends to sound more wooly and underwater sounding, yet still with some harshness. Get the SRA just right, and the HF's snap into focus, and the smallest details will be retrieved from the groove with ease. How do you align SRA? After studying the then and still current crop of vinyl mastering lathes, it was found that the SRA of the groove was at a majority average of about 1 degree forward tilt from vertical. That is, the stylus itself should make a 1 degree angle forward, or away from the tonearm. This can be seen using a bright backlight for the stylus as it plays under normal tracking force and alignment. An easy way to eyeball the proper angle is to construct a visual reference using a protractor and a piece of paper, and drawing a line that is superimposed on a perfectly vertical line that is one degree off of vertical, and tilting toward 11 o'clock. Have this paper handy and use it to A/B the angle of the stylus. SRA or stylus rake angle, as opposed to VTA, was first discussed in a November 1980 Popular Electronics article titled: "Phonograph Playback: It's better than you think." by myself and Dr. Maier, p. 48. The article touched on several aspects of vinyl playback, some of which are relevant to this discussion. I urge readers to look it up at the library, as it has some excellent SEM photomicrographs of groove walls, and some interesting diagrams. The next mention of SRA was a two page note by the editors of High Fidelity in the March, 1981 issue on page 31. They basically recap the research at Discwasher about SRA. The big article was a multipage article with diagrams, graphs and photo's in Audio magazine, March 1981, page 21, "More Than One VTA", again by Dr. Maier and myself. This went into detail, presenting distortion graphs, etc., outlining the difference between VTA and SRA quantifiably. The article included instructions on how to set up your phono cartridge for best compromise VTA/SRA, for those who did not wish to re-adjust for each record. Jon Risch ------------------------------ From: Thorsten@tnt-audio.com Subject: Re: VTA observations and questions Date: 13 Jul 1998 20:42:16 GMT Message-ID: <6odrf8$ajg$1@agate.berkeley.edu> References: <6o33qc$dpl$1@agate.berkeley.edu> <6o36rv$ghr$1@agate.berkeley.edu> <6o39pr$osd@news01.aud.alcatel.com> <6o3cat$q9i@news01.aud.alcatel.com> <6o3dqt$mjo$1@agate.berkeley.edu> <6o5frf$df7$1@agate.berkeley.edu> <6o5m9v$fc@news01.aud.alcatel.com> Hi there, > I moved the turntable to the sandbox at the same time I increased the > cartridge *body* VTA from 5 to 10 degrees. The overall effect was > that the sound became bright and hard (bad) but with better bass > definition (good). There is "lesson" one. Intelligent tweaking involves never to change more one variable deliberatly. If you change too many things at the same time it is hard to acertain exactly which change in setup led to which sonical change.... Taking things step-by-step takes initially more time but will in the long run pay by incresing your understanding of the matter and by preventing (potentially costly) mistakes (like purchasing one expensive to undo what another expensive tweak did in the first place....). > I hope the greater bass definition came from the sandbox and the > bright, hard sound came from the 30 degree VTA. If so I should have > some pretty good sound this weekend when I take the cartridge *body* > back down somewhere between 0 and 5 degrees VTA. As said. Experiment carefully and explore the whole range of possible adjustments. As cartridges are individually made and often with significant manual work, no two of them are 100% identical.... > This is an Ortofon MC-10 Super Mk 2, a low (0.2 mV) output MC. It has > a "Fritz Geiger Type II nude" stylus, whatever that is. . . The Fritz Gyger II Stylus is a Line-Stylus and has the same Profile my own Cartridge uses. Other Profiles would be Van denHul or for example the Ogura Pathfinder. All these denote slightly different cut's of the Diamond and have different sonic properties. > I used to listen to high output MCs and this cartridge was an > experiment. It's the first low output MC I have used. The experiment > was successful because this one sounds clearly better than any other > cartridge I've used. I'd agree with that. High Output MC's often have too high a moving mass.... > Agreed. It's currently aligned according to the DB dual point gauge. > Tracking force seems optimal at 2.0 grams. I find that my Goldring Elite tracks perfectly well at 1.9 g and increasing it further produces a "sat upon" sound. Much less than the 1.9 g and mistracking results.... Again, this is somewhat dependant on the individual Cartridge you have. > > Cartridge Loading is another issue. I have found in a few instances > > that the Manufacturers recomendation will not give the best > > results. I'm currently running a Cartridge with a recommended loading > > of 100 Ohm and less than 500pF Capacitance with 10 Ohm and 22nF as > > First rule of engineering says, "If it ain't broke, don't fix it" As you seem not entirely happy with the sound, it is "broke".... > I don't intend to mess around with the loading. Besides, my preamp (a > Rotel RC-990 BX) doesn't have adjustable loading. It's set to 47 kOhm > on MM and 100 Ohm on MC. This is a pretty minimalist preamp, just a > volume control and function selector. Inside, it's also a very clean, > minimalist design. I certainly don't want to add new components into > the signal path, especially when the sound I'm getting now is so > good. Is it soo good? Let me just state "for the record" that the changes obtained by changing the loading can be more dramatic than those from changing VTA.... As for the story of how I arrived at the 10 ohm loading for my Cartridge, have a read here: http://www.tnt-audio.com/sorgenti/elite1.html One option to try out different loadings would be to make a small adaptor to be inserted between Preamp Input and Phono-Lead, that would allow to try different loadings. Once you have convinced yourself that the 100 Ohm from the factory are fine simply remove the Adaptor and leave things as they are or replace the 100 ohm with whatever value you found works best.... My own Preamp (I designed it - so it is my own ;-) ) uses a second set of RCA Jacks in parallel to the Input Jacks. There I plug in an additional RAC Plug with the appropriate components soldered in. > Thanks for the good advice. I'll post again next week when I have > some results. Good luck and don't forget to Enjoy the Music.... Kind regards Thorsten. ====================================== e-mail: Thorsten@tnt-audio.com Visit TNT-Audio on the Web - the only advertising free audio web-zine. http://www.tnt-audio.com ====================================== - ----== Posted via Deja News, The Leader in Internet Discussion ==----- http://www.dejanews.com/rg_mkgrp.xp Create Your Own Free Member Forum ------------------------------ From: johno@vcd.hp.com (John Ongtooguk) Subject: Re: VTA observations and questions Date: 13 Jul 1998 20:51:01 GMT Message-ID: <6odrvl$asi$1@agate.berkeley.edu> References: <6o33qc$dpl$1@agate.berkeley.edu> <6oddl3$grj@news01.aud.alcatel.com> Jon M. Risch (jrisch@cybertron.com) wrote: : When the SRA is set too high (the cartridge angled tipped forward), : it tends to sound bright and fatiguing, with it set too low : (cartridge angled tipped back) it tends to sound more wooly and : underwater sounding, yet still with some harshness. Get the SRA just : right, and the HF's snap into focus, and the smallest details will be : retrieved from the groove with ease. One of the better details to listen for is a nice long decay on bells and triangles and such, where the soundstage will also end up being better defined with a good adjustment. John Ongtooguk (johno@vcd.hp.com) ------------------------------ From: "Michael R. Clements" Subject: Re: VTA observations and questions Date: 13 Jul 1998 21:27:49 GMT Message-ID: <6odu4l$qt1@news01.aud.alcatel.com> References: <6o33qc$dpl$1@agate.berkeley.edu> <6o36rv$ghr$1@agate.berkeley.edu> <6o39pr$osd@news01.aud.alcatel.com> <6o3cat$q9i@news01.aud.alcatel.com> <6o3dqt$mjo$1@agate.berkeley.edu> <6o5frf$df7$1@agate.berkeley.edu> <6o5m9v$fc@news01.aud.alcatel.com> Michael R. Clements wrote: > I moved the turntable to the sandbox at the same time I increased the > cartridge *body* VTA from 5 to 10 degrees. The overall effect was > that the sound became bright and hard (bad) but with better bass > definition (good). > I hope the greater bass definition came from the sandbox and the > bright, hard sound came from the 30 degree VTA. If so I should have > some pretty good sound this weekend when I take the cartridge *body* > back down somewhere between 0 and 5 degrees VTA. > Thanks for the good advice. I'll post again next week when I have > some results. Well I said I'd experiment and report back, and I've done so. Went back and took the cartridge off the arm again to redo the alignment. Took off my custom super-VTA spacer to get the cartridge body parallel to the surface of the record. Realigned to the two-point DB gauge to the point where the cartridge was perfectly tangent (to the naked eye) at both NULL points, and the VTA (of the cartridge body) was zero on thick (220 gram) records like MoFis, and *slightly* more on thin (normal) records like Opus 3. Set tracking force (using the Shure gauge) to 1.9 grams; tested at 1.95 and 1.85 to make sure the force was really 1.9 grams. Set anti-skating appropriately. The sound had just a tad less bass definition than it did with 10 degrees more VTA. But the bass was going deeper with this setup. Could be it was just as tight, just going deeper made it sound different. Whatever it was, the kick drums on my Audioquest Bruce Katz band records sounded quite lifelike, super deep with great resolution. Overall the sound had lost its hard edge, but was still precise and detailed. I can't say it sounded "warmer", but it did sound rich and lush. The annoying echoing noises on my Opus 3 piano recordings were more tolerable (did Opus 3 ever make a good piano recording? Their string recordings are superb but all four of the Opus 3 piano recordings I have suck.) The Telefunkens were still on the bright side of realism, but were more enjoyable as there was greater midrange detail and the bass came out better. Midrange, especially piano, sounds noticeably better than before. Acoustic instruments sound more lifelike and good jazz just rocks like never before. I ended up increasing the VTA ever so slightly, so that on a 180 gram record the cartridge body is just barely tilted, adding about 1 degree to the VTA. Spent several enjoyable hours listening to music in beautiful high fidelity splendor thanks to your good advice. Learned something about cartridge setup, too. BTW, the sandbox makes a noticeable improvement. Experience has taught me that vibration isolation and setup is extremely important for good analog sound, and when you go with a low output MC, it's more critical than ever. The low output MCs are more sensitive and finicky, but when you get them right, the sound quality is simply stunning. Regards, ------------------------------ From: "Michael R. Clements" Subject: VTA Tips and Discoveries Date: 20 Jul 1998 18:24:41 GMT Message-ID: <6p0219$lo8@news01.aud.alcatel.com> Last weekend I wanted to play around with different VTA angles to get the best sound possible out of my setup. The problem was that my turntable (a Thorens TD318 Mk 2) does not have easily adjustable VTA. You have to take the cartridge off the arm and put a different width spacer between cartridge and arm, which means a complete realignment. I found a way to adjust the VTA and get the best sound I've gotten so far out of the system. Thought I'd drop a note so others might benefit from my experience. . . Found a more convenient way to adjust VTA (probably reinvented the wheel here, but oh well. . .). Went down to TAP Plastics and got 4 square feet of 20 mil clear acrylic vinyl. If I had to guess I'd say each sheet is about 1/32" inch thick. Cut it out into 12" circles and to avoid wrinkling I cut 8 slits spaced every 45 degrees. Adjusted the cartridge/arm assembly with (what appeared to be) just a tad (about 1 degree) too much VTA. Then put the acrylic spacers between the TT platter and the mat. With all 4 spacers installed, the VTA was less than the recommended 20 degrees (cartridge body was at a slightly negative angle). With none, it was slightly positive. Now I could adjust VTA without touching the arm, merely by putting a different number of spacers between the TT platter and mat. Sound differences: With all 4 spacers, the angle of the cartridge body was just a bit negative (back edge lower than the front edge). The sound had audible breakup distortion at times. It was also soft and fuzzy, not very involving sounding. When I looked from the front of the turntable at the angle of the actual needle while playing (with a magnifying glass and a light) the needle was at a slightly negative angle, like this "/". As I removed spacers the sound became more precise and the distortion went away. There was a very hard-to-get spot where the distortion was gone but the precision was there -- but the sound was still warm and lush sounding with no hardness. This spot was hard to get because it seemed the closer I got to the "perfect" VTA, the more sensitive slight changes were. When I was way off, changing it a few degrees didn't do much. But when it got really close, the adjustment got extremely sensitive and changes of less than 1 degree were audible. I discovered that the best sound was with *no* spacers. Then I measured it in this position. The cartridge body was ever so slightly (about 1 degree) away from parallel to the record (in the direction of increasing VTA). But the needle tracking the groove was as perfectly up-and-down vertical as I could see. Now the recommended tracking force range is 1.6 to 2.0 grams. I have it set somewhere between 1.9 and 1.95 grams. This force is higher than the midpoint of 1.8 grams, thus tends to decrease the VTA. I would suspect that at 1.8 grams the needle would be straight up and down when the cartridge body was parallel to the record. The extra 1 degree or so of VTA that I have applears to be just counteracting the slightly increased tracking force that I'm using. The sound I'm getting now is pretty satisfying. Deep but not overpowering bass, smooth and detailed midrange, great sounding highs. Brass instruments -- trumpets and trombones especially -- sound absolutely spectacular. My old 1950s mono jazz records never sounded better. Even Opus 3 piano recordings -- which tend to have annoying resonances in the midrange -- are listenable. And the high quality Chesky, Audioquest, BMG and MoFi vinyl sounds superb. ------------------------------ From: Curtis Leeds Subject: Re: VTA Tips and Discoveries Date: 20 Jul 1998 20:10:56 GMT Message-ID: <6p088g$pvn@news01.aud.alcatel.com> References: <6p0219$lo8@news01.aud.alcatel.com> Michael R. Clements wrote: > Last weekend I wanted to play around with different VTA angles to get > the best sound possible out of my setup. The problem was that my > turntable (a Thorens TD318 Mk 2) does not have easily adjustable VTA. > You have to take the cartridge off the arm and put a different width > spacer between cartridge and arm, which means a complete realignment. Spacers also change the mass of the pickup arm, so it introduces another variable into the process. > I found a way to adjust the VTA and get the best sound I've gotten > so far out of the system... Found a more convenient way to adjust > VTA (probably reinvented the wheel here, but oh well. . .). Went > down to TAP Plastics and got 4 square feet of 20 mil clear acrylic > vinyl... Cut it out into 12" circles and to avoid wrinkling I cut 8 > slits spaced every 45 degrees. Adjusted the cartridge/arm assembly > with (what appeared to be) just a tad (about 1 degree) too much > VTA. Then put the acrylic spacers between the TT platter and the > mat. Such an arrangement also decouples the LP from the platter - and that's usually not a good idea either. - - *************************************************** cleeds@idt.net "I stood unwound beneath the skies And clouds unbound by laws. The cryin' rain like a trumpet sang And asked for no applause." (Bob Dylan) *************************************************** ------------------------------ From: Floyd Sense Subject: Re: VTA Tips and Discoveries Date: 21 Jul 1998 15:19:52 GMT Message-ID: <6p2bio$2s5@news01.aud.alcatel.com> References: <6p0219$lo8@news01.aud.alcatel.com> In my experience, the best way to observe the differences caused by varying the VTA is to be able to vary it while the music is playing. The ET-2 arm allows such real-time VTA adjustment. Without attempting to describe what the differences sound like, I can tell you that there is clearly a point where the music just sounds better. With the ET-2, you can sweep back and forth over that point several times until you're satisfied that you have the best sounding position. [quoted text deleted -- deb] ------------------------------ From: Bob Trosper Subject: Re: VTA Tips and Discoveries Date: 21 Jul 1998 23:05:10 GMT Message-ID: <6p36r6$cmu$1@agate.berkeley.edu> References: <6p0219$lo8@news01.aud.alcatel.com> <6p088g$pvn@news01.aud.alcatel.com> <6p0be6$ruh@news01.aud.alcatel.com> <6p1b9n$8vv$1@agate.berkeley.edu> The VPI jr. at least, and I thought the VPI HW series in general, lets you adjust the VTA runtime by varying the height of the platter. This wouldn't seem to be any different than varying the arm height. Am I missing something here? In any case, I just put the sucker up on 4 tins of canned goods (the adjustment screw is underneath the bearing well), level it, adjust the VTA, bring it back down, and re-level. Rest assured I don't do that for every record. If I were that neurotic I'd leave it up on the cans. I wonder if peas would sound better than corn? Does solid pack pumpkin have superior damping properties to yams in heavy syrup? How about light syrup? I must write J-ten and get him onto this new tweak :=) - - Bob T. ------------------------------ From: "Michael R. Clements" Subject: Re: VTA Tips and Discoveries Date: 20 Jul 1998 21:05:10 GMT Message-ID: <6p0be6$ruh@news01.aud.alcatel.com> References: <6p0219$lo8@news01.aud.alcatel.com> <6p088g$pvn@news01.aud.alcatel.com> Curtis Leeds wrote: > > wheel here, but oh well. . .). Went down to TAP Plastics and got 4 > > square feet of 20 mil clear acrylic vinyl... Cut it out into 12" > > circles and to avoid wrinkling I cut 8 slits spaced every 45 > > degrees. Adjusted the cartridge/arm assembly with (what appeared > > to be) just a tad (about 1 degree) too much VTA. Then put the > > acrylic spacers between the TT platter and the mat. > Such an arrangement also decouples the LP from the platter - > and that's usually not a good idea either. So it's possible the increased distortion I heard was caused by this decoupling rather than by the VTA changes? Is this decoupling distortion audible? If so, how would you characterize it? What should one listen for? ------------------------------ From: Curtis Leeds Subject: Re: VTA Tips and Discoveries Date: 21 Jul 1998 06:08:55 GMT Message-ID: <6p1b9n$8vv$1@agate.berkeley.edu> References: <6p0219$lo8@news01.aud.alcatel.com> <6p088g$pvn@news01.aud.alcatel.com> <6p0be6$ruh@news01.aud.alcatel.com> Michael R. Clements wrote: > > > ...Went down to TAP Plastics and got 4 square feet of 20 mil > > > clear acrylic vinyl... Cut it out into 12" circles and to avoid > > > wrinkling I cut 8 slits spaced every 45 degrees. Adjusted the > > > cartridge/arm assembly with (what appeared to be) just a tad > > > (about 1 degree) too much VTA. Then put the acrylic spacers > > > between the TT platter and the mat. And I noted: > > Such an arrangement also decouples the LP from the platter - > > and that's usually not a good idea either. Now Michael R. Clements asks: > So it's possible the increased distortion I heard was caused by this > decoupling rather than by the VTA changes? Yes. You introduced two variables (a change in VTA/SRA, and a change in LP to platter coupling). When you introduce two variables simultaneously, it's difficult to know how each contributes to the outcome. This is all part of why it's hard for me to accept a tonearm that doesn't permit VTA adjustment. - - *************************************************** cleeds@idt.net "I stood unwound beneath the skies And clouds unbound by laws. The cryin' rain like a trumpet sang And asked for no applause." (Bob Dylan) *************************************************** ------------------------------ End of Rec.Audio.High-End Digest -- Cartridge VTA ************************************************* To subscribe to the Rec.Audio.High-End Digest, send the command subscribe rahe-digest in the body of a message to . If you want to subscribe something other than the account the mail is coming from, such as a local redistribution list, then append that address to the "subscribe" command; for example, to subscribe "local-audio" send subscribe rahe-digest local-audio@your.domain.net All past Digest issues are accessible via anonymous ftp from the server "ftp.graphics.cornell.edu" in the directory "pub/rahe/digest". World Wide Web access is via the URL "ftp://ftp.graphics.cornell.edu/pub/rahe/digest". Digests beginning with Volume 63 (November 1997) are available from the Majordomo server at the above address. Details on accessing list server archives, as well as other useful information on interacting with the server, may be obtained by sending the command "help" to the server. Subject: [teres] RAHE cartridge aligment guides and use Date: Thu, 17 Aug 2000 07:44:40 -0700 From: Steve Zettel, Steve Zettel To: teres@aiko.com Same as before. Public domain info as far as I can tell. Steve Z near Libby, MT USA From: owner-rahe-digest@graphics.cornell.edu (Rec.Audio.High-End Digest) To: rahe-digest@graphics.cornell.edu Subject: Rec.Audio.High-End Digest -- Cartridge Alignment (Special Edition) Reply-To: rahe-usenet@graphics.cornell.edu Sender: owner-rahe-digest@graphics.cornell.edu Errors-To: owner-rahe-digest@graphics.cornell.edu Precedence: bulk Rec.Audio.High-End Digest Friday, June 19 1998 Cartridge Alignment In this issue: cartridge alignment guide ? Re: cartridge alignment guide ? Re: cartridge alignment guide ? Re: cartridge alignment guide ? Re: cartridge alignment guide ? Re: cartridge alignment guide ? Re: cartridge alignment guide ? Re: cartridge alignment guide ? Re: cartridge alignment guide ? Re: cartridge alignment guide ? Re: cartridge alignment guide ? Re: cartridge alignment guide ? Re: cartridge alignment guide ? Re: cartridge alignment guide ? Re: cartridge alignment guide ? Re: cartridge alignment guide ? Re: cartridge alignment guide ? Re: cartridge alignment guide ? Re: cartridge alignment guide ? Re: cartridge alignment guide ? ---------------------------------------------------------------------- Date: 14 Jun 1998 03:48:37 GMT From: "Michael R. Clements" Subject: cartridge alignment guide ? Message-ID: <6lvh6l$1de$1@agate.berkeley.edu> After leaving behind all my cartridge alignment stuff (including my protractor, turntable platter guide and painstakingly carefully made VTA angle cutouts) while visiting my parents, and having them throw it all away by accident, I'm looking for replacement stuff. Anyone know of any good sources in the SF Bay Area to get all this kind of stuff, including but not limited to: 1. tracking force scale/gauge 2. azimuth/overhang guide (the kind that sits on the turntable platter and you adjust the arm to it) 3. VTA angle scale/gauge (protractor or cutouts) I prefer adjusting overhang at a single-point near the leadout groove because this helps reduce distortion on problematic records that have high cutting levels or > 25 minutes per side. I'll consider mailorder too but prefer to but this stuff from a real shop that knows turntables well. Thanks in advance for the advice, ------------------------------ Date: 14 Jun 1998 16:32:31 GMT From: johno@vcd.hp.com (John Ongtooguk) Subject: Re: cartridge alignment guide ? Message-ID: <6m0tuv$12l$1@agate.berkeley.edu> References: <6lvh6l$1de$1@agate.berkeley.edu> Michael R. Clements (mrc01@flash.net) wrote: : After leaving behind all my cartridge alignment stuff (including my : protractor, turntable platter guide and painstakingly carefully made : VTA angle cutouts) while visiting my parents, and having them throw it : all away by accident, I'm looking for replacement stuff..... : : I prefer adjusting overhang at a single-point near the leadout groove : because this helps reduce distortion on problematic records that have : high cutting levels or > 25 minutes per side. If you want to use your own 'null points' you should probably just work out the math using your own assumptions, instead of relying upon the assumptions that someone else used. Usually you start with assumptions on over what distance on the LP you would like to minimize the tracking error and then solve for two null points, which also requires solving an optimum turntable spindle to tonearm pivot distance for a given length of tonearm. For a given distance over which you want to minimize the tracking error you end up with two null points that change very little over a wide range of tonearm lengths. Like you have come to prefer, it's probably better to live with a bit more error at the start and in the middle of an LP in order to minimize the potentially high errors at the end of an LP. John Ongtooguk (johno@vcd.hp.com) ------------------------------ Date: 14 Jun 1998 19:29:29 GMT From: "Michael R. Clements" Subject: Re: cartridge alignment guide ? Message-ID: <6m18ap$ae9@news01.aud.alcatel.com> References: <6lvh6l$1de$1@agate.berkeley.edu> <6m0tuv$12l$1@agate.berkeley.edu> John Ongtooguk wrote: > If you want to use your own 'null points' you should probably just > work out the math using your own assumptions, instead of relying > upon the assumptions that someone else used. Usually you start with And those assumptions would be. . . I'm guessing here. . . That you want the cartridge to be tangent to the groove the needle is tracking? The next question would be one of overhang, or how long to make the tonearm. You can effectively change the length of the tonearm by positioning the cartridge further "in" or further "out" along the arm. Once you adjust tangency, if you change overhang you're no longer tangent -- or at least not at that point, you may be tangent at a different point. And vice versa. Ah, I understand now. This is all irrelevant. Explanation: All you do is cut out a cardboard or plastic "record" with a spindle hole in the center, then draw a radius line out from the spindle hole to the edge of the "record". Now decide where on this radius line you want to adjust the cartridge so it is perfectly tangent at this point. This will be somewhere near the "average" lead-out groove position, which is about 2.5" from the center of the "record". Then you make a bunch of parallel lines, all perpendicular to the radius line. You use these parallel lines and the perpendicular radius line to adjust the cartridge straight at the point you picked. Is that right? If so, the only difference between different alignment gauges is where they put the zero-error tangent point. ------------------------------ Date: 15 Jun 1998 08:57:38 -0400 From: johno@vcd.hp.com (John Ongtooguk) Subject: Re: cartridge alignment guide ? Message-ID: <6m35o2$ihv@jamesv.warren.mentorg.com> References: <6lvh6l$1de$1@agate.berkeley.edu> <6m0tuv$12l$1@agate.berkeley.edu> <6m18ap$ae9@news01.aud.alcatel.com> Michael R. Clements (mrc01@flash.net) wrote: : All you do is cut out a cardboard or plastic "record" with a spindle : hole in the center, then draw a radius line out from the spindle hole : to the edge of the "record". Now decide where on this radius line you : want to adjust the cartridge so it is perfectly tangent at this : point. This will be somewhere near the "average" lead-out groove : position, which is about 2.5" from the center of the "record". Then : you make a bunch of parallel lines, all perpendicular to the radius : line. You use these parallel lines and the perpendicular radius line : to adjust the cartridge straight at the point you picked. : : Is that right? If so, the only difference between different alignment : gauges is where they put the zero-error tangent point. It doesn't matter if 'somehwere' and 'about' are acceptable :^) I've found music down to a radius of 2.25in on some LPs and due to the nature of tracking error it changes a lot at the minimum radius, more than at the start and in the middle of an LP. It's best to adjust at two null points as you're changing offset angle as well as overhang, where obviously a wide range of angles and overhangs can produce a null at one point, but only one combination is a solution for a given set of assumptions. I've assumed that music extends from 2.25in to 5.75in on LPs, so minimizing the tracking error produces similar errors at 2.25in, 3.23in, and 5.75in. A nominal 9in tonearm needs to be set up to a spindle to pivot distance of 8.332in, and the null points at 2.469in and 4.691in only change 0.005in for tonearms (set up properly) that range from 7in to 12in. To set up the cartridge within +/- 0.1 degree per inch error of the minimum that can be obtained you need to adjust the overhang within +/- 0.005in and the offset angle within +0.2/-0.1 of target, which is difficult to do. If you can only hold +/-0.020in and +/-0.5deg then you more than double the error at 2.25in compared to the minimum attainable. A static alignment using the cartridge body or stylus may not always correlate with the dynamic conditions, which is another souce of error. John Ongtooguk (johno@vcd.hp.com) ------------------------------ Date: 15 Jun 1998 13:43:43 -0400 From: "Michael R. Clements" Subject: Re: cartridge alignment guide ? Message-ID: <6m3mgf$606@spectrum.warren.mentorg.com> References: <6lvh6l$1de$1@agate.berkeley.edu> <6m0tuv$12l$1@agate.berkeley.edu> <6m18ap$ae9@news01.aud.alcatel.com> <6m35o2$ihv@jamesv.warren.mentorg.com> John Ongtooguk wrote: > set of assumptions. I've assumed that music extends from 2.25in to > 5.75in on LPs, so minimizing the tracking error produces similar > errors at 2.25in, 3.23in, and 5.75in. A nominal 9in tonearm needs > to be set up to a spindle to pivot distance of 8.332in, and the > null points at 2.469in and 4.691in only change 0.005in for tonearms > (set up properly) that range from 7in to 12in. To set up the cartridge > within +/- 0.1 degree per inch error of the minimum that can be > obtained you need to adjust the overhang within +/- 0.005in and > the offset angle within +0.2/-0.1 of target, which is difficult > to do. If you can only hold +/-0.020in and +/-0.5deg then you more > than double the error at 2.25in compared to the minimum attainable. > A static alignment using the cartridge body or stylus may not always > correlate with the dynamic conditions, which is another souce of > error. OK, my understanding of all this techno-speak is that if I'm building my own gauge follow these rules: 1. Draw a radius line from the center of the gauge to the its outer edge. 2. Mark two points on the line, 2.469" and 4.691" from the center 3. Draw some lines perpendicular to the radius line near these points (for aligning the sides of the cartridge body) 4. Draw some lines parallel to the radius line near these points (for aligning the front edge of the cartridge body) This would make a two-point alignment, where the arm would have zero tracking angle error at each of these two points -- one near the lead-out groove, one near the beginning of the record. ------------------------------ Date: 15 Jun 1998 16:53:07 -0400 From: Curtis Leeds Subject: Re: cartridge alignment guide ? Message-ID: <6m41jj$j5a@jamesv.warren.mentorg.com> References: <6lvh6l$1de$1@agate.berkeley.edu> <6m0tuv$12l$1@agate.berkeley.edu> <6m18ap$ae9@news01.aud.alcatel.com> <6m35o2$ihv@jamesv.warren.mentorg.com> John Ongtooguk wrote: > A static alignment using the cartridge body or stylus may not always > correlate with the dynamic conditions, which is another souce of > error. How can this be? Provided that the cartridge mounting hardware is tight, how can its tangency under playback conditions be different than during set-up? - - *************************************************** cleeds@idt.net "I stood unwound beneath the skies And clouds unbound by laws. The cryin' rain like a trumpet sang And asked for no applause." (Bob Dylan) *************************************************** ------------------------------ Date: 15 Jun 1998 16:52:48 -0400 From: Curtis Leeds Subject: Re: cartridge alignment guide ? Message-ID: <6m41j0$j4f@jamesv.warren.mentorg.com> References: <6lvh6l$1de$1@agate.berkeley.edu> <6m0tuv$12l$1@agate.berkeley.edu> John Ongtooguk wrote (regarding the null points chosen for setting phono cartridge tangency): >...Like you have come to prefer, it's probably > better to live with a bit more error at the start and in the > middle of an LP in order to minimize the potentially high errors > at the end of an LP. The tracking error towards the center of an LP is not "potentially high" (relative to the rest of the LP) if you use the standard two-point alignment scheme. It may be that tracking error is slightly more *audible* in the inner grooves, but the audibility of that can be reduced by choosing a cartridge with a line-contact type stylus. In my system, I've never heard any artifact attributable to changing cartridge tangency as the cartridge traverses the LP surface. (That's using line-contact styli and two-point alignment.) - - *************************************************** cleeds@idt.net "I stood unwound beneath the skies And clouds unbound by laws. The cryin' rain like a trumpet sang And asked for no applause." (Bob Dylan) *************************************************** ------------------------------ Date: 15 Jun 1998 21:58:54 GMT From: "Michael R. Clements" Subject: Re: cartridge alignment guide ? Message-ID: <6m45eu$4s8@news01.aud.alcatel.com> References: <6lvh6l$1de$1@agate.berkeley.edu> <6m0tuv$12l$1@agate.berkeley.edu> <6m41j0$j4f@jamesv.warren.mentorg.com> Curtis Leeds wrote: > choosing a cartridge with a line-contact type stylus. In my > system, I've never heard any artifact attributable to > changing cartridge tangency as the cartridge traverses the > LP surface. (That's using line-contact styli and two-point > alignment.) Not even on Telefunken's Brandenburg Concertos 2, 4, 6 reissue? On this one I get audible distortion in the leadout groove no matter what I do. And the cutting level isn't very loud either. Maybe it's a defective record but Paul Wakeen of Media Access says others have reported this problem. I'm hoping with a two point alignment this problem may go away. What do you think of Ongtooguk's two points (2.469" and 4.691")? What do you use on your alignments? ------------------------------ Date: 15 Jun 1998 21:58:29 GMT From: Curtis Leeds Subject: Re: cartridge alignment guide ? Message-ID: <6m45e5$4r0@news01.aud.alcatel.com> References: <6lvh6l$1de$1@agate.berkeley.edu> <6m0tuv$12l$1@agate.berkeley.edu> <6m18ap$ae9@news01.aud.alcatel.com> <6m35o2$ihv@jamesv.warren.mentorg.com> <6m3mgf$606@spectrum.warren.mentorg.com> Michael R. Clements wrote: > OK, my understanding of all this techno-speak is that if I'm building my own > gauge follow these rules: > > 1. Draw a radius line from the center of the gauge to the its outer edge. > 2. Mark two points on the line, 2.469" and 4.691" from the center > 3. Draw some lines perpendicular to the radius line near these points (for > aligning the sides of the cartridge body) > 4. Draw some lines parallel to the radius line near these points (for aligning > the front edge of the cartridge body) > > This would make a two-point alignment, where the arm would have zero tracking > angle error at each of these two points -- one near the lead-out groove, one > near the beginning of the record. Yes and no. Ya' really gotta love (hate) the LP. First, you've made assumptions about the relative audibility of tracking error across the LP by selecting these null points. Second, your gauge aligns only the stylus tip and cartridge shell - not the actual cantilever. So if the cantilever is just a bit out of alignment, you're going to suffer azimuth error unless you otherwise adjust for it. That's the value of the mirrored gauges such as CartAlign and WallyTracktor. - - *************************************************** cleeds@idt.net "I stood unwound beneath the skies And clouds unbound by laws. The cryin' rain like a trumpet sang And asked for no applause." (Bob Dylan) *************************************************** ------------------------------ Date: 16 Jun 1998 00:44:55 GMT From: Curtis Leeds Subject: Re: cartridge alignment guide ? Message-ID: <6m4f67$ju6$1@agate.berkeley.edu> References: <6lvh6l$1de$1@agate.berkeley.edu> <6m0tuv$12l$1@agate.berkeley.edu> <6m18ap$ae9@news01.aud.alcatel.com> John Ongtooguk wrote: > > If you want to use your own 'null points' you should probably just > > work out the math using your own assumptions, instead of relying > > upon the assumptions that someone else used. and Michael R. Clements answers: > > And those assumptions would be. . . I'm guessing here. . . That you > want the cartridge to be tangent to the groove the needle is > tracking? Tangent, yes. But where? At what points? These decisions effect the tracking error (and, hence, distortion) limits of the final set-up. > The next question would be one of overhang, or how long to make the > tonearm. You can effectively change the length of the tonearm by > positioning the cartridge further "in" or further "out" along the > arm. On some arms, yes. On others, the cartridge mounting holes are fixed. Also, if you fiddle with the "effective length" of the arm, you are also altering the arm's offset angle and azimuth. So as a practical matter, arms have a fixed effective length. > Once you adjust tangency, if you change overhang you're no longer > tangent -- or at least not at that point, you may be tangent at a > different point. And vice versa. Ah, I understand now. This is all > irrelevant. It is very relevant if you are seeking highest possible performance. >Explanation: > > All you do is cut out a cardboard or plastic "record" with a spindle > hole in the center, then draw a radius line out from the spindle hole > to the edge of the "record". Now decide where on this radius line you > want to adjust the cartridge so it is perfectly tangent at this > point. This will be somewhere near the "average" lead-out groove > position, which is about 2.5" from the center of the "record". Not necessarily. In fact, if you set one of the null points this close to the average leadout groove, you will suffer higher average tracking error across the rest of the LP. > Then > you make a bunch of parallel lines, all perpendicular to the radius > line. You use these parallel lines and the perpendicular radius line > to adjust the cartridge straight at the point you picked. But you cannot achieve tangency at more than two points. > Is that right? If so, the only difference between different alignment > gauges is where they put the zero-error tangent point. Yes. But there can be a wide variation in performance - dependent in part on stylus geometry - based on where those points are set. - - *************************************************** cleeds@idt.net "I stood unwound beneath the skies And clouds unbound by laws. The cryin' rain like a trumpet sang And asked for no applause." (Bob Dylan) *************************************************** ------------------------------ Date: 16 Jun 1998 00:47:24 GMT From: Curtis Leeds Subject: Re: cartridge alignment guide ? Message-ID: <6m4fas$jvg$1@agate.berkeley.edu> References: <6lvh6l$1de$1@agate.berkeley.edu> <6m0tuv$12l$1@agate.berkeley.edu> <6m41j0$j4f@jamesv.warren.mentorg.com> <6m45eu$4s8@news01.aud.alcatel.com> I wrote: > >...In my > > system, I've never heard any artifact attributable to > > changing cartridge tangency as the cartridge traverses the > > LP surface. (That's using line-contact styli and two-point > > alignment.) And Michael R. Clements asks: > Not even on Telefunken's Brandenburg Concertos 2, 4, 6 reissue? On > this one I get audible distortion in the leadout groove no matter > what I do. And the cutting level isn't very loud either. Maybe it's a > defective record but Paul Wakeen of Media Access says others have > reported this problem. Well, I don't have this LP, so I can't answer your question. Is this the only LP that you're having trouble with? If so, it sounds like a defective LP to me. That others report the same problem with it does nothing to dispel that notion. > I'm hoping with a two point alignment this problem may go away. The two-point alignment system isn't going to help in those critical inner grooves; if that is your overiding concern, you should experiment with the one-point method. > What > do you think of Ongtooguk's two points (2.469" and 4.691")? What do > you use on your alignments? Establishing the nulls is a matter of judgement, becuase you have to make some assumption as to the mimimum groove radius. I really like the WallyTracktor gauge, and it sets the nulls at 66mm and 121mm. - - *************************************************** cleeds@idt.net "I stood unwound beneath the skies And clouds unbound by laws. The cryin' rain like a trumpet sang And asked for no applause." (Bob Dylan) *************************************************** ------------------------------ Date: 16 Jun 1998 05:31:59 GMT From: "Michael R. Clements" Subject: Re: cartridge alignment guide ? Message-ID: <6m500f$232$1@agate.berkeley.edu> References: <6lvh6l$1de$1@agate.berkeley.edu> <6m0tuv$12l$1@agate.berkeley.edu> <6m18ap$ae9@news01.aud.alcatel.com> <6m4f67$ju6$1@agate.berkeley.edu> Curtis Leeds wrote: > > and Michael R. Clements answers: > > > > And those assumptions would be. . . I'm guessing here. . . That you > > want the cartridge to be tangent to the groove the needle is > > tracking? > > Tangent, yes. But where? At what points? These decisions > effect the tracking error (and, hence, distortion) limits of > the final set-up. It's a question of geometry. You can set it up so that there's a single point where the cartridge is tangent, or two points. Where you put these points is a judgement call. You're always reducing distortion at one point, at the expense of increasing it somewhere else. If you use a two point method, you'll get more distortion at the leadout groove even if one of the two points is near the groove. That's because in a two point alignment, the curve the needle sweeps as it moves from the outside to the inside of the record, has more curvature near the leadout groove than in the single point method. So if you want better sound in the middle of the record at the expense of more distortion near the leadout groove, use a two point alignment. If you want to minimize leadout groove distortion at the expense of more distortion in the beginning and middle of the record, use a one point alignment. My personal experience is that distortion near the leadout groove is a LOT more audible than anywhere else. So I'm willing to accept more distortion at the beginning and middle of the record -- which is less noticeable -- to get rid of the audible distortion at the leadout groove. Of course it all depends on how much you give up for what you get, which is why it's a judgement call. Try different ones and see what you like. . . > > Then > > you make a bunch of parallel lines, all perpendicular to the radius > > line. You use these parallel lines and the perpendicular radius line > > to adjust the cartridge straight at the point you picked. > > But you cannot achieve tangency at more than two points. Yeah, I should have been more precise. You'd draw multiple parallel lines merely for convenience. The needle is always placed at the point(s) you've already picked along the radius, and the multiple parallel lines are there to eye the alignment from above w.r.t. the cartridge. > > Is that right? If so, the only difference between different alignment > > gauges is where they put the zero-error tangent point. > > Yes. But there can be a wide variation in performance - > dependent in part on stylus geometry - based on where those > points are set. YES, Certainly!! > > What > > do you think of Ongtooguk's two points (2.469" and 4.691")? What do > > you use on your alignments? > > Establishing the nulls is a matter of judgement, becuase you > have to make some assumption as to the mimimum groove > radius. I really like the WallyTracktor gauge, and it sets > the nulls at 66mm and 121mm. The WallyTractor settings and John's recommended settings are very close, viz: WallyTractor 66 mm = 2.598" vs. John's 2.469", about 1/8" difference WallyTractor 121mm = 4.764 vs. John's 4.691", about 1/14" difference These are so close that I think it'd be pretty darn tough to actually hear the difference. I'd be tempted to go with John's, because they're a bit closer to the center of the record where most of the distortion is going to be. Actually, I'm going to make at least three different gauges and compare. One matching the WallyTractor, one matching John's, and a third like the MoFi GeoDisc or the DB alignment disc. Thanks for all the great info. ------------------------------ Date: 16 Jun 1998 07:25:36 -0400 From: johno@vcd.hp.com (John Ongtooguk) Subject: Re: cartridge alignment guide ? Message-ID: <6m5kng$jk6@jamesv.warren.mentorg.com> References: <6lvh6l$1de$1@agate.berkeley.edu> <6m0tuv$12l$1@agate.berkeley.edu> <6m41j0$j4f@jamesv.warren.mentorg.com> Curtis Leeds (cleeds@idt.net) wrote: : John Ongtooguk wrote (regarding the null points chosen for : setting phono cartridge tangency): : >...Like you have come to prefer, it's probably : > better to live with a bit more error at the start and in the : > middle of an LP in order to minimize the potentially high errors : > at the end of an LP. : The tracking error towards the center of an LP is not : "potentially high" (relative to the rest of the LP) if you : use the standard two-point alignment scheme. It may be that : tracking error is slightly more *audible* in the inner : grooves, but the audibility of that can be reduced by : choosing a cartridge with a line-contact type stylus. In my : system, I've never heard any artifact attributable to : changing cartridge tangency as the cartridge traverses the : LP surface. (That's using line-contact styli and two-point : alignment.) There are different ways to weight the error and to attempt to minimize it, but a simple one is 'degrees of tracking error per inch of record radius'. When tracing across an LP the error will tend to look like: * * * * * * * * start end where the error goes from some negative value to zero to some positive value to zero to some negative value again. The zeros are the null points, and to minimize the error the magnitude of the error at the negative values, which are the assumed start and end points of music on the LP, and at the maximum positive value in the center of the LP, should all be the same and at the minimum attainable. At the end of the LP the slope of the error is steeper than elsewhere, where the error can increase quickly if the alignment wasn't performed correctly or if the alignment didn't assume music extending to such a small radius on the LP. So, one method of minimizing tracking error is to use two null points of adjustment, where error will be the same at the assumed start and end points as well as at some point between. John Ongtooguk (johno@vcd.hp.com) ------------------------------ Date: 16 Jun 1998 14:19:57 -0400 From: johnafr@aol.com (JohnAFR) Subject: Re: cartridge alignment guide ? Message-ID: <6m6d0d$ksv@jamesv.warren.mentorg.com> References: <6m5kng$jk6@jamesv.warren.mentorg.com> John Ongtooguk wrote:>So, one method of minimizing tracking error is to use two null> points of adjustment, where error will be the same at the assumed> start and end points as well as at some point between. Another method, which is probably more common, is to attempt to minimize distortion at the beginning and end points as well as the maximum point in-between the nulls. This results in a larger maximum tracking error at the outer edge of the record than in the middle or the innermost groove because less distortion is produced from a given tracking error in the outer grooves than by the same tracking error at the inner grooves. In fact, the null points of 66mm and 121mm recommended by Curtis Leeds are designed specifically for this purpose. They are based on minimizing peak distortion between an extreme inner groove of 60.3mm and an outermost groove of 146mm using the equation k(e/r), where: k is a scaling constant, e is the tracking error, and r is the record groove radius. Another equation which provides almost identical results is k(tan(e))/r.In addition to these two methods, some people prefer to minimize average distortion between the groove extremes by minimizing the area under the distortion curve. This results in very low distortion in the middle part of the record between about 65mm and 138mm, but produces sharply rising distortion on the extreme innermost grooves and somewhat higher distortion on the outermost grooves. The justification for this type of alignment is that many records don't have grooves much below 65mm and the overall distortion in the middle of the record will be very low for the greatest amout of playing time. Null points for this type of alignment are usually around 70 to 73mm for the inner null and between 112 to around 116 for the outer null.Aligning a cartridge for a different set of null point than was intended for a specific tonearm will require changing the offset by angling the cartridge in the headshell. My guess is that most modern tonearms are designed for the 66/121 alignment, but this is only a guess. I know my SME Series III is designed for these null points and so are Graham tonearms according the white paper on Bob Grahams web site. I use a DB Protractor, which is also designed for 66/121, but actually can be used to align to any other null points.Several months ago I developed an Excel 97 spreadsheet to model tonearm geometry. It allows experimentation with different tonearm lengths, offsets, and overhangs, while observing, graphically, how the null points and tracking error change. It also allows optimizing null points for minimum peak or average distortion using the Excel Solver function. If anyone would like a copy, I'd be happy to send it to you.Best Regards,John Elison ------------------------------ Date: 16 Jun 1998 20:16:31 GMT From: johno@vcd.hp.com (John Ongtooguk) Subject: Re: cartridge alignment guide ? Message-ID: <6m6jqv$isq@news01.aud.alcatel.com> References: <6lvh6l$1de$1@agate.berkeley.edu> <6m0tuv$12l$1@agate.berkeley.edu> <6m18ap$ae9@news01.aud.alcatel.com> <6m4f67$ju6$1@agate.berkeley.edu> <6m500f$232$1@agate.berkeley.edu> Michael R. Clements (mrc01@flash.net) wrote: : So if you want better sound in the middle of the record at the expense : of more distortion near the leadout groove, use a two point : alignment. If you want to minimize leadout groove distortion at the : expense of more distortion in the beginning and middle of the record, I don't think so. The reason for using two points is to attempt to control the tracking error, which is governed by the overhang and offset angle adjustments relative to the rest of the fixed turntable and LP geometry, without having to specifically adjust the overhang and offset angle. If you want to only use one point you will need to adjust the overhang and offset angle to specific values at the null point, as a range of such values at one point can produce zero tracking error and yet not be the desired solution. John Ongtooguk (johno@vcd.hp.com) ------------------------------ Date: 16 Jun 1998 15:03:28 GMT From: johno@vcd.hp.com (John Ongtooguk) Subject: Re: cartridge alignment guide ? Message-ID: <6m61g0$7fm@news01.aud.alcatel.com> References: <6lvh6l$1de$1@agate.berkeley.edu> <6m0tuv$12l$1@agate.berkeley.edu> <6m18ap$ae9@news01.aud.alcatel.com> <6m35o2$ihv@jamesv.warren.mentorg.com> <6m3mgf$606@spectrum.warren.mentorg.com> Michael R. Clements (mrc01@flash.net) wrote: : OK, my understanding of all this techno-speak is that if I'm building my own : gauge follow these rules: : : 1. Draw a radius line from the center of the gauge to the its outer edge. : 2. Mark two points on the line, 2.469" and 4.691" from the center : 3. Draw some lines perpendicular to the radius line near these points (for : aligning the sides of the cartridge body) : 4. Draw some lines parallel to the radius line near these points (for aligning : the front edge of the cartridge body) : : This would make a two-point alignment, where the arm would have zero tracking : angle error at each of these two points -- one near the lead-out groove, one : near the beginning of the record. If you have a typical 9in tonearm roughly check that the spindle to pivot distance is correct, where it needs to be close enough for the amount of overhang adjustment that is available. A suggestion on the gage is to make it in two pieces, one for each null point. You would then prevent the platter from moving, using 'door stops' made from erasers or whatever, and then would rotate each gage about the spindle until the null point is being traced by the tonearm, and adjust the offset angle and overhang. This is obviously an iterative process. Maybe a pinhole will make it easier to locate the stylus, and be careful about anti-skate messing up the alignment. John Ongtooguk (johno@vcd.hp.com) ------------------------------ Date: 16 Jun 1998 20:16:39 GMT From: johno@vcd.hp.com (John Ongtooguk) Subject: Re: cartridge alignment guide ? Message-ID: <6m6jr7$ist@news01.aud.alcatel.com> References: <6m5kng$jk6@jamesv.warren.mentorg.com> <6m6d0d$ksv@jamesv.warren.mentorg.com> JohnAFR (johnafr@aol.com) wrote: : John Ongtooguk wrote: : :: So, one method of minimizing tracking error is to use :: two null points of adjustment, where error will be the :: same at the assumed start and end points as well as at :: at some point between. : Another method, which is probably more common, is to attempt : to minimize distortion at the beginning and end points as well : and end points as well as the maximum point in-between the nulls. : This results in a larger maximum tracking error at the outer edge : of the record than in the middle or the innermost groove because : less distortion is produced from a given tracking error in the : outer grooves than by the same tracking error at the inner grooves. : In fact, the null points of 66mm and 121mm recommended by Curtis : Leeds are designed specifically for this purpose. They are based : on minimizing peak distortion between an extreme inner groove of : 60.3mm and an outermost groove of 146mm using the equation k(e/r), : where: k is a scaling constant, e is the tracking error, and r : is the record groove radius. Another equation which provides : almost identical results is k(tan(e))/r .... (the format was poorly suited for a standard screen width so I tried to shorten the line lengths, and hope I didn't mess it up) A constant k used in k(e/r) isn't going to produce different results than just using (e/r), as like you say it's just a constant. As an imaginary example shows: error radius e/r k=2 k=0.5 k=200 2.3 deg 5.8in 0.4 deg/in 0.8 0.2 80 1.4 3.5 0.4 0.8 0.2 80 0.9 2.2 0.4 0.8 0.2 80 So there is no real difference between using 'degrees of tracking error per inch of record radius', e/r, and k(e/r), when it comes time to minimize the error using whatever technique. Over the range noted (it appears that you're using degrees) the k(tan(e))/r (assuming k=1) is almost identical in variation to the above, which means that it's really no different than just using e/r. error radius tan e (deg) tan e (rad) k(tan(e))/r (deg) 2.3 deg 5.8in 0.040 -1.119 0.0069 1.4 3.5 0.024 5.798 0.0070 0.9 2.2 0.016 1.260 0.0071 Assuming that music extends from 60.3mm (2.37in) to 146mm (5.75in) is pretty close to the assumption of 2.25in and 5.75in mentioned earlier. If you end up with more tracking error at the start of a record than in the middle maximum and at the assumed end it appears that you're minimizing the error with some other weighting technique than you've described, as your weighting factors as you've noted and as we've shown are just constants. You mentioned living with more error at the start and end of a record in order to minimize it in the middle but that tends to produce LOTS of error at the end of some records, and in my opinion is unacceptable. You also mentioned minimizing the error under the curve but again that will tend to produce lots of error at the end of some LPs. You can observe that most LPs don't have music extending as far as some and adjust for most LPs, but again you will end up with lots of error on some LPs. The tradeoff might be a 20% increase in tracking error on all LPs played in order to avoid a 2X to 5X increase in error at the end of some LPs, but that's just a guess based upon some of the results that I recall from a long time ago. John Ongtooguk (johno@vcd.hp.com) ------------------------------ Date: 18 Jun 1998 16:35:10 GMT From: johnafr@aol.com (JohnAFR) Subject: Re: cartridge alignment guide ? Message-ID: <6mbfju$ei6@news01.aud.alcatel.com> References: <6m6d0d$ksv@jamesv.warren.mentorg.com> In article <6m6d0d$ksv@jamesv.warren.mentorg.com>, johnafr@aol.com (JohnAFR) writes: >Several months ago I developed an Excel 97 spreadsheet >to model tonearm geometry. It allows experimentation with >different tonearm lengths, offsets, and overhangs, while >observing, graphically, how the null points and tracking error >change. It also allows optimizing null points for minimum >peak or average distortion using the Excel Solver function. >If anyone would like a copy, I'd be happy to send it to you. I have received several requests for my spreadsheet, but when I replied my e-mail was returned as undeliverable. If you have not received a reply to your request, please send me another request specifying your exact e-mail address in the body of your message and I'll try again. Best Regards, John Elison ------------------------------ Date: 18 Jun 1998 18:13:15 GMT From: johnafr@aol.com (JohnAFR) Subject: Re: cartridge alignment guide ? Message-ID: <6mblbr$i1r@news01.aud.alcatel.com> References: <6m6jr7$ist@news01.aud.alcatel.com> John Ongtooguk wrote: > So there is no real difference between using 'degrees of tracking > error per inch of record radius', e/r, and k(e/r), when it comes > time to minimize the error using whatever technique. Yes, this is true, but we are minimizing tracking error divided by radius, not tracking error directly. > Assuming that music extends from 60.3mm (2.37in) to 146mm (5.75in) > is pretty close to the assumption of 2.25in and 5.75in mentioned > earlier. If you end up with more tracking error at the start of > a record than in the middle maximum and at the assumed end it > appears that you're minimizing the error with some other weighting > technique than you've described, as your weighting factors as > you've noted and as we've shown are just constants. I think the confusion stems from fact that I view tracking error as the actual angular deviation from groove tangency while you consider tracking error to be the angular deviation divided by groove radius. It appears that we both use exactly the same weighting approach except that I use an innermost groove of 2.374in instead of 2.25in. If you plug that larger inner groove value into your program you will come out with null points of 2.596in (66mm) and 4.764in (121mm). I plugged your inner groove radius into my spreadsheet and came up with the same numbers you posted in an earlier message to r.a.h-e. With regard to my reasoning on the larger inner groove dimension, I really don't have a well thought out rationale except that my SME Series III tonearm was designed to the 66/121mm null point configuration, which seems to be a more common alignment, today. I play mainly audiophile pressings from the 1970s and 1980s, very few of which contain grooves smaller than 60mm. I did measure a sample of 42 records one day and found the average inner groove radius to be 69.7mm. Only two of the 42 records contained inner grooves less than 60.3mm. One was 59mm and the other was 59.5mm. I know that 42 records is a very small sampling, but due to the type of records I play, the 66/121 alignment is probably better for me. The reasoning behind my scaling constant, "k," is that it allows me to plot the error/radius curve on the same graph as the error curve. I consider error/radius to be a proxy for the distortion resulting from tracking error. In fact, I developed another spreadsheet to calculate actual geometric distortion as a function of tracking error, groove radius and stylus tip velocity. This analysis assumes a perfect stylus in the sense that zero tracking error produces zero distortion. From this analysis it appears that error/radius can roughly approximate actual distortion for a given stylus tip velocity above 10cm/s by selecting an appropriate "k." > You mentioned living with more error at the start and end of a > record in order to minimize it in the middle but that tends > to produce LOTS of error at the end of some records, and in > my opinion is unacceptable. You also mentioned minimizing the > error under the curve but again that will tend to produce lots > of error at the end of some LPs. You can observe that most LPs > don't have music extending as far as some and adjust for most > LPs, but again you will end up with lots of error on some LPs. > The tradeoff might be a 20% increase in tracking error on all > LPs played in order to avoid a 2X to 5X increase in error at > the end of some LPs, but that's just a guess based upon some > of the results that I recall from a long time ago. Yes, I agree. However, some people prefer the alignment that comes from minimizing the area under the error/radius curve. Like you, I prefer to minimize the peak or maximum points of this curve. Sorry for the confusion. I hope this clears up any misunderstanding we may have had. Best Regards, John Elison ------------------------------ Date: 19 Jun 1998 16:09:05 -0400 From: grahams@polk.co.uk (Graham Shore) Subject: Re: cartridge alignment guide ? Message-ID: <6megh1$848@eyrie.graphics.cornell.edu> References: <6lvh6l$1de$1@agate.berkeley.edu> Here is a simple method to calculate the parameters required to align your cartridge. Try these for yourself and listen to the results - if you don't like it then simply revert to what you had before! Assuming the innner radius of the record to be r1, and the outer to be r2. The radii at which zero tracking error occurs are r0 and r0' r0 = 2 * r1 * r2 / ( (1 - 1 / 2^0.5) * r1 + (1 + 1 / 2^0.5) * r2 ) r0' = 2 * r1 * r2 / ( (1 + 1 / 2^0.5) * r1 + (1 - 1 / 2^0.5) * r2 ) Assuming D is distance from arm pivot to platter centre, d is the overhang and L is the effective length (D + d) then d = (D^2 + r0 * r0')^0.5 - D and d = L - (L^2 - r0 * r0')^0.5 Example. r2, the outer radius of an IEC standard LP is set at 146mm. r1 varies, of course, and AFAIK there is no set minimum, so we will use 58mm as a good bet. To find the points of zero tracking error, r0 and r0' :- r0 = 2 * 58 * 146 / ( (1 - 1 / 2^0.5) * 58 + (1 + 1 / 2^0.5) * 146 ) = 16936 / ( (1 - 0.7071) * 58 + (1 + 0.7071) * 146 ) = 16936 / (16.9882 + 249.2366) = 63.62 mm and similarly r0' = 16936 / (99 + 42.76) = 119.47 mm To calculate the overhang 'd', for a pivot to platter centre of, say, 215 mm, d = (215^2 + (63.62 * 119.47) )^0.5 - 215 = 53825.6814^0.5 - 215 = 232.0036 - 215 = 17.0036 mm So, practical values are r0 = 64 mm r0' = 119 mm d = 17 mm. Notes: Points of zero tracking error are independant of PU arm length, and are a function of min/max record radii. To draw up a protractor (using some graph paper), scribe an arc of radius L, and a small arc of radius D to indicate centre of platter (origin). From the origin, scribe arcs at the two points of zero tracking, to intersect the arc of the stylus. At these points construct parallel and perpendicular lines to allow visual inspection of cartridge alignment. Punch a 6mm hole (standard hole punch I think) at the origin. -- Best Regards, Graham Shore. ------------------------------ End of Rec.Audio.High-End Digest -- Cartridge Alignment ******************************************************* To subscribe to the Rec.Audio.High-End Digest, send the command subscribe rahe-digest in the body of a message to . If you want to subscribe something other than the account the mail is coming from, such as a local redistribution list, then append that address to the "subscribe" command; for example, to subscribe "local-audio" send subscribe rahe-digest local-audio@your.domain.net All past Digest issues are accessible via anonymous ftp from the server "ftp.graphics.cornell.edu" in the directory "pub/rahe/digest". World Wide Web access is via the URL "ftp://ftp.graphics.cornell.edu/pub/rahe/digest". Digests beginning with Volume 63 (November 1997) are available from the Majordomo server at the above address. 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