SRA and VTA are used to describe the relationship of individual components to the record surface in degrees. Once the two components are glued together they are an assembly. The relationship then becomes a means (VTA) to an end (SRA).
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No. VTA is the angle of the cantilever relative when the cartridge is horizontal relative to the record. This is set by the cartridge manufacturer (it's usually 20 degrees). SRA is the angle of the stylus relative to the record surface. The text-book correct angle is 92 degrees. Ideally, you adjust the arm parametres VTF, overhang, azimuth), you then adjust SRA to 91-92 degrees by lifting or lowering the arm, then, if you're still there, readjust overhang, re-check SRA, and play music. Final fine-tuning by ear. Good luck! |
dangcaonguyen So the VTA cannot be adjusted by the end user?The VTA can be adjusted by raising or lowering the pickup arm, but the optimum VTA is determined by the phono cartridge manufacturer and - to an extent - the VTA of the actual cutting stylus. |
Strictly speaking the VTA is the angle made by the stylus tip to the cantilever attachment to the cartridge. It is a bit different than the angle of the cantilever itself. The SRA is the angle that the stylus rake makes with the recording. It can be different than the angle of the stylus (if by that is meant the angle of a line bisecting the stylus front to back). The rake is the sharpest parts on the sides of the stylus forming ellipse or line contact with the record groove, left and right. Perfect alignment would have the rake be at the same angle as that of the cutting stylus when the record masters were cut. Somewhere around the 92 degrees mentioned. It can be different as cutting angles were not always at 92 degrees. Hence for the happily obsessive, different SRAs for different recordings--and on the fly. Of course the SRA and VTA cannot be aligned independently. Conical styli have no rake (and no SRA) and the only thing then to align is the VTA at around 20 degrees. |
Modern cartridges are very well made. You set the VTF to the manufacturer's recommendation then raise or lower the tonearm until the arm is perfectly parallel to the record. This will give you both the correct VTA and SRA. Trying to set SRA by viewing the stylus is a ......difficult way to proceed even if you have loops and a micro protractor. |
melm Strictly speaking the VTA is the angle made by the stylus tip to the cantilever attachment to the cartridge. It is a bit different than the angle of the cantilever itself.That's a fine distinction but it's absolutely correct. Conical styli have no rake (and no SRA) and the only thing then to align is the VTA at around 20 degrees.Actually, conical styli are almost immune to VTA alignment, so anywhere even close to 20 degrees will be more than fine. (The spec becomes increasingly critical as the stylus shape narrows to elliptical to hyperelliptical to microline ...) That's why some phono cartridges with spherical styli remain so popular - they're easy to set up. But overhang is as critical with spherical styli as any other stylus shape. |
mijostyn ... raise or lower the tonearm until the arm is perfectly parallel to the record. This will give you both the correct VTA and SRA.That approach should get you close to proper VTA. Whether the result is "correct" hinges on your tolerance for error, which varies among audiophiles. For many - myself included - the parallel pickup arm is just a starting point. |
@wlutke Please explain more detail. Thanks It means if you are talking about the relationship of the stylus to the record surface in degrees, you say SRA. If you are talking about the relationship of the cantilever (measured from a line drawn from the stylus contact point to the cantilever pivot) you say VTA. If you are talking about a procedure (setting SRA), it is cause (VTA) and effect (SRA). Means to an end. |
dangcaonguyen If I adjusted the VTA by 1 degree, will the SRA change with the same 1 degree?It will be very, very, very close, but it’s not exactly a 1:1 relationship. That’s because VTA is the angle between the surface of the record and that of the stylus tip in the groove and a line drawn through the cantilever to its pivot point. SRA is that the vertical center line of the stylus contact patches make with the groove ridges. The groundbreaking and still-definitive work on this was by Risch & Meier. See the March, ’81 issue of Audio magazine. It is online here. The illustrations will make this more clear. |
petg60 1mm change in VTA will affect 0,19 degrees of SRA, so no it will be less than 1 degree.VTA is measured in degrees, not millimeters. VTA is an angle, not a distance. But even if you intend to say that a 1mm change in pickup arm height results in a .19 degree change in SRA, you can’t state that as an absolute. The correlation between change in arm height and change in VTA/SRA is contingent on the length of the pickup arm. That’s one of the advantages of a longer pickup arm. In any event, I’d like to see the math that supports your claim. |
Thank you all for the answers, but so far no one have answered directly my question: If I adjusted the VTA by 1 degree, will the SRA change with the same 1 degree? Since I muddled this one up the other day let me clear it up now. The answer is yes- sort of. VTA generally refers to the angle of the tone arm, although technically it is the angle of the cantilever. Almost always when people say VTA they’re talking about the tone arm. Since the cartridge is fixed in the arm and the arm base is what is adjusted it gets real technical splitting hairs between the two. SRA Stylus Rake Angle is the angle of the stylus to the record. The idea is to have the angle of the stylus match the angle of the cutter that was just to cut the groove. SRA is the angle that counts. In a fixed, static, diagrams on paper world if you raise the arm to increase VTA by 1 degree then yes SRA will also change by 1 degree. The problem is records are cut in an engineering process with a tool similar to the cutting edge on a lathe. The cutter head is powerful and moved back and forth and up and down with great precision. The way we play them back is a completely different thing altogether. Unlike the cutter head that is held in the same alignment the stylus is at the end of a cantilever that is free to wiggle around in some rubbery donut, at the end of a long arm that is free to move up and down and left and right and this whole contraption is bouncing around all over the place. The way it works, because of the way its balanced, if you dig into it real close the 1 degree does not translate into 1 degree because the cantilever moves based on VTF and VTF is set at one angle so when the angle changes the VTF changes and this in turn changes the SRA. Not much, hardly any. The point is to understand the Rube Goldberg imprecise wobbly nature of the thing. Then totally aside from VTF (and warped records) the SRA is still never gonna stay where its set because this whole thing is always moving. Playing a record the groove modulates and this drags on the stylus pulling the cantilever and changing SRA. These angles are simply constantly changing all over the place all the time no matter how carefully aligned or what you do. Its even worse than this. The stylus doesn’t even trace the groove. Oh sometimes it does. But a lot of the time its bouncing from one spot to another sort of sampling the groove. This is because the groove puts so much energy into the stylus, it travels up the cantilever, reflects back down, and the stylus being the least massive part of the whole thing is like the end of a whip. The point of my incredibly long-winded dissertation is to drive home the hopelessness of trying to align a cartridge by obsessing on such matters. Its not that they’re a total waste of time. They are, and they aren’t. They are in the sense they get you in the ballpark. They aren’t in that you still need to find your seat. The one and only way of doing that is by ear. Listening by ear you will be able to hear which is better. How many degrees that is, who cares? The differences we are talking about here are not measured in degrees. They are not measured in arc-seconds. They are not even measured by micrometers. How could they be? The smallest undulations on a groove are on the order of the size of some large organic molecules. Tracing such incomprehensibly small undulations with a stylus that on that scale looks like a boulder, and a boulder bouncing from wall to wall to boot, is as Peter Ledermann loves to say something that should not work. Yet it works phenomenally well. Especially when tweaked to perfection by ear. |
Hi, @cleeds, i don’t have a formula though below made sense to me. VTA is an angle but changes by upward/downward arm movement in mm. Greater changes in SRA are created by VTF than VTA. The VPI is a 12" arm, but as we’re in the 21st century let’s go metric :-) For ease of maths lets say the VPI is 300mm effective length. That means that if the arm pivot is seen as the centre of a circle the stylus describes a circle, diameter 600mm. That gives a circumference of the circle as 1885.2mm (600 X pi (pi taken as 3.142)). Thus in a full 360 degrees the stylus will travel 1885.2 mm. To alter the stylus angle (SRA) one degree the pivot must move 1885.2/360 = 5.23mm. Here remember that relative to the cartridge the pivot will not go just upwards but describe an arc, but for our purposes I think it acceptable to say that a 5.23mm change in arm height will alter SRA by 1 degree. Likewise we can calculate what SRA change a 1 mm change in arm height will produce i.e. 1/5.23 = 0.19 degree, about a fifth of one degree. As an aside it’s interesting to apply this formula to a cartridge cantilever, which is less than 10mm long (as little as 1.5mm) - just think of the huge, massive, GIGANTIC! SRA changes the tiniest movement due to warps will produce... https://www.tnt-audio.com/sorgenti/vta_e.html |
Cleed, excellent geometry. If you think things sound better a little off parallel knock your self out. All my cartridges are have very small fine line styli. Moving off parallel only make things sound worse so I don't bother any more. It could be psychological as I have no way to AB it. There you are. Oh, I am a neurotic perfectionist. I is usually not a fun trait. |
millercarbon VTA generally refers to the angle of the tone arm, although technically it is the angle of the cantilever.Nope, you’re wrong again. Let @melm explain: ... VTA is the angle made by the stylus tip to the cantilever attachment to the cartridge. It is a bit different than the angle of the cantilever itself.Millercarbon your claim here is also false: if you raise the arm to increase VTA by 1 degree then yes SRA will also change by 1 degree.To be fair to you, it will be very, very close to a 1 degree change. But it won’t be exactly 1 degree and that you don’t understand that shows you’re as confused now as when you stated earlier that VTA and SRA are the same thing. Hey millercarbon, don’t you think it’s time you get your facts straight about LP geometry? I made it easy for you by linking to the definitive work on VTA/SRA by Risch & Meier published in Audio magazine. And when you’re done with that, please do some research on HTA. It’s one of the most critical aspects of phono cartridge alignment, yet it seems to have completely escaped your attention. |
SRA is the actual objective. VTA only a method of getting close to proper SRA (lets say 92 degrees, like the angle of the cutter when making the master). It is a whole lot easier to see the cantilever shaft than seeing the stylus tip, thus VTA of the cantilever is the method of getting close to SRA. Then you listen, you refine by ear, actually refining SRA. it ain't easy. Start with cartridge maker's recommended VTA of the cantilever, 15 degrees being common. The end of the cantilever might be bent by design (or see example 3 below), the stylus tip is fixed onto the cantilever at a different angle, to result in achieved 92 degrees. The tracking force you use will put more or less force on the suspension of the cantilever, (i.e. rubber the cantilever shaft passes thru into the cartridge body, and that will change the VTA, so you need to set tracking force first, and double/triple check your VTA. Change tracking force: check/reset VTA. Note: suspension could be aged, weak, brittle, .... view the cantilever shaft, not the cartridge body, not the arm. Three examples: 1. Shure V15 series of cartridges are named for their design of 15 degree VTA. When new, if manufactured and assembled perfectly, set tracking force, adjust arm height: IF you get the more easily seen cantilever at 15 degrees, then, by manufacturing intent, the stylus tip will be at 92 degrees to the record surface. You are unable to see the stylus tip, but presumably SRA is 92 degrees or close. 2. This Ortofon, VTA 23 degrees yields SRA +/- 90 degrees, then listen/adjust https://www.ortofon.com/hifi/products/hifi-cartridges/mc-a95/set-up/ 3. My Friends Grace, Bent Cantilever (low rider) His cantilever is damaged, the shaft is bent, the 'low rider' condition, the bottom of the cartridge barely clears the record surface. Factory VTA no longer valid. It sounded bad, he called me. I came over, saw the bent shaft, stylus not user replaceable. So, until dealt with, what can be done? Checked TT level/spindle/pivot/overhang, all good. Azimuth also good. a. reduce tracking force to very near minimum, to increase the space between cartridge body and lp surface a squeak. b. Raised back of arm, increased SRA as much as I could without the front of the cartridge touching the record surface. It's not ideal, best I could achieve, no listening refinement possible, as SRA is a squeak less than 90 degrees. c. Listen. Much better, even though the shaft is bent, it still responds to groove modulations, it is amazing how good a damaged cantilever can perform IF the Azimuth and SRA are good. Meanwhile, we found someone in NJ who can fix the Grace Cartridge, off it will go soon. |
There is so much incorrect info here, and now on the setting of correct SRA that I hope I will be forgiven for repeating an old post on the subject: Here is my $.02 keeping in mind that success will depend on stylus shape and the quality of associated components. And some experience listening. Keep in mind that VTA setting should NOT be a tone control. There is one correct setting for a disk. But with a disk you should be close enough not to change for each disk unless you are particularly obsessive. Many of us are. Setting vta (really, sra) is like aligning the reading head on a tape machine. There should be one correct setting. It's not really an opinion issue. But it's also not very easy for most of us. All best done by ear. Even with expensive microscopes, last setting is by ear. Save your money. Find a recording that people say is good for hearing the differences when you adjust SRA. Do a search here and elsewhere; there are lots of suggestions out there.* If you can't find one, take a record of a female singer and listen to it over and over 'till you know it very well. I have used Joni Mitchell's "Blue." Make sure it's something you like 'cause you'll be listening to it a lot. Set your tone arm to level and listen to the recording a few times. Level is only a beginning point. It is rare for absolutely level to be the end point with a sophisticated stylus shape and components. Read all you can about your cartridge and see if reviewers or users have a consensus suggesting tail up or down. Change the angle in that direction a very small amount and listen to the whole record. You are listening for the voice and instruments to "pop" making them more 3 dimensional. It's quite subtle, but it's there with the a stylus having a clear rake. Do that again and again in very small increments. If you do not hear improvement soon go back and stay at level. If your reading does not come up with a tail up or down consensus. You may have to try this in both directions. If you do not hear this kind of improvement, go back and stay at level. Go on to adjust azimuth which many (including Peter Ledermann) consider the most important adjustment. * Flying Fish HDS 701, "Sauerkraut and Solar Energy" is a popular suggestion, though one listens for other things using this disk--the bass fiddle. And great record besides. If you do get this record, there's a lot of posts on how to use it. |
One thing to keep in mind- the SRA at 92 degrees is an average. In reality the mastering engineer didn’t set the cutter stylus that way. He set it up so it would cut a silent groove. The cutter stylus only goes about 10 hours, then you have to remove the cutter head and replace the stylus. At that point, you have to installed the head and get it aligned and calibrated, and then start fiddling with the height of the cutter and the stylus temperature until you get something that works. The result is every LP is slightly different. Fun huh? |
Hi, as i have no formula to prove when 1 degree of VTA= 1 degree of SRA please enlight me if wrong. How long should be the arm or the cantilever for this to happen? In normal arms, never, 1 degree change in VTA would correspond to much less than 1 degree of SRA, so not close enough. So all depends from the arm and the cantilever. |
Dear @dangcaonguyen : """
I understand a lot more...... Can we trust on the cartridge manufacture on the 92 degree SRA? I mean, if we can set the top of the cartridge perfectly parallel to the platter, then we can get very close to 92 degree? """ Certainly that you are not understanding very well the overall subject through all the information posted here. You can trust in nothing but your ears on the subject because: each cartridge manufacturer puts/attach the stylus tip to the cantilever in different angle ( around 19°-23°. ), all LP are cutted different ( read atmasphere posts. ), you own 120gr., 140 gr., 180 gr., 200 gr., etc LP's, all LP's comes with surface waves, etc, etc. Your VTA/SRA set up works as you want it only in that LP and not exactly the same with other LPs. R. |
if we can set the top of the cartridge perfectly parallel to the platter, then we can get very close to 92 degree?If all is well, probably so. But I've seen cartridges where the stylus was incorrectly mounted, making the proper SRA impossible. It never sounded right either- finally traced the issue to that defect. So sound quality is a good indicator :) |
Fortunately Atmasphere I have not seen an incorrectly mounted stylus for a long time. I always view a new cartridge under magnification to make sure the stylus is generally in the right position and shape before I mount it. In the old days, late 60's early 70's one in three cartridges would have an incorrectly angled cantilever or wacky stylus. Hopefully this is not going on with today's inexpensive cartridges. The more expensive cartridges have been excellent in my experience. |
