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« Reply #45 on: December 29, 2020, 11:41:54 PM » |
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Hi Anthony,
Aha! My protractor apparently is not a copy of the original SME protractor (even if it was sold as such) but something else entirely - the null point is at 66mm which suggests Baerwald alignment. Maybe I should ditch it and get the Tracking Wizard arc protractor — I have one for my Fidelity Research and it's a joy to use.
I suspected as much! ![ropies_dance](https://www.lencoheaven.net/forum/Smileys/yarex2/ropies_dance.gif) I would advise against using an arc protractor as the primary tool since the cumulative errors can be worse than using just a 2 point protractor - I would suggest using the arc protractor to get you in the ballpark and then using a 2 point Stevenson 1B protractor to refine the offset and overhang. Better still, given the fixed offset of the SME headshell you won't be able to achieve any other alignment than that which SME intended. My guess is that whoever made the protractor you have probably just extended the radius from 60.3 to 66mm but kept the same outline shape - I would be VERY suprised if they did otherwise. The fact that they set it to 66mm (presumably retaining the same offset outline of the headshell) clearly indicates that they didn't understand what they were/are doing and don't have a thorough understanding of the SME arm.... ... in which case why don't you just reposition the spindle hole position to match the 60.3mm radius and check to see if that makes sense with the spindle/pivot distance? With a 12" arm, Stevenson 1B gives you a truly universal solution to play all 3 record sizes with a peak weighted distortion that is still better than a 9" arm optimised for an IEC LP. Remember also, that the vertical bearing offset is intended to match the headshell offset - if you intend to shift to a slotted headshell and go for a true Baerwald solution, then you will need to be very careful in setting the arm height to the exact value you need otherwise you will likely have to tweak the azimuth to compensate for the error.
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stratokaster83
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« Reply #46 on: December 30, 2020, 12:01:58 AM » |
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To be honest, I play almost exclusively LPs so other record sizes are of limited interest to me.
But it's interesting that you advise against using the arc protractor. In my experience the TrackingWizard one was spot on for my FR54 (probably because I did a good job mounting the tonearm at exactly 230mm from the spindle). With this protractor aligning the cartridge is a 2-step process: first you adjust the overhang, and then refine the offset angle using the provided grid. The sound was excellent even with line contact styli that are rather fussy when it comes to proper alignment.
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flood2
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« Reply #47 on: December 30, 2020, 12:27:51 AM » |
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To be honest, I play almost exclusively LPs so other record sizes are of limited interest to me.
But it's interesting that you advise against using the arc protractor. In my experience the TrackingWizard one was spot on for my FR54 (probably because I did a good job mounting the tonearm at exactly 230mm from the spindle). With this protractor aligning the cartridge is a 2-step process: first you adjust the overhang, and then refine the offset angle using the provided grid. The sound was excellent even with line contact styli that are rather fussy when it comes to proper alignment.
Just to clarify, I advise against the arc protractor as the sole tool - the accuracy depends on having the actual pivot/spindle distance matching the protractor value EXACTLY ... not to within a ballpark value. If the values do not match exactly to 0.0000000000....000001 (you get the idea), then the arc being traced can never match the protractor arc. It may "look" like the stylus is tracing the arc, but the radius of curvature will be different. The magnitude of the error will depend on the deviation of the true pivot/spindle distance to the protractor. What then happens is that you have introduced simultaneous errors to both overhang and offset. Combine that with a spindle hole that isn't a perfect tolerance fit and you have added yet another source of error . I am exaggerating of course, but the arc protractor is challenging enough to use to achieve the desired results with a fixed base arm; it is definitely not suitable with a sliding base arm with a fixed offset headshell without additional tools since you are changing the pivot/spindle distance as you adjust the stylus position. Hence, why I suggest using the arc protractor to set a rough overhang, then shift to a normal 2 point protractor to refine the solution. Overhang is more critical to set particularly as the effective length increases (thus giving a shorter overhang distance). The combined errors for overhang and offset result in the longer arms potentially having a larger maximum tracking error than for a shorter arm. If you wish to optimise for an LP, you will have to change the headshell to a conventional slotted design and then make the corresponding change to azimuth due to the deviation from the vertical bearing offset angle and recalibrate the antiskate scale. I have gone through this exercise with my SL1200 arm - I prefer an alignment optimised for DIN LPs (close enough to Stevenson 1A) rather than the default Technics option.
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stratokaster83
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« Reply #48 on: February 11, 2021, 10:35:47 PM » |
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I now have an assortment of tools that are supposedly designed specifically for SME 3012 Series II and I still have no idea how to align it properly ![embarrassed](https://www.lencoheaven.net/forum/Smileys/yarex2/embarrassed.gif) I have a later SME one-point protractor which has its null point at 66mm from the spindle. It is impossible to align the tonearm using this tool, even with a slotted headshell. I have an original (old) SME alignment protractor with a single null point that is somewhere between 60 and 60.5mm. I assume it matches the "canonical" alignment (60.3mm inner null, 117mm outer null). I can only hit the null point if I slide the tonearm all the way back and slide the cartridge all the way back in its slots. It is impossible to hit the null point using the stock headshell. If I use the stock headshell with any of my cartridges, I end up missing the null point by several mm. I have an arc protractor which is generated using SME-specified values: 294mm spindle to pivot, 11mm overhang. The thing is, when my tonearm is at roughly 294mm from the spindle, it is absolutely impossible to get 11mm of overhang. This would require a headshell which is only ~3cm in length and such a thing doesn't exist. As I mentioned previously, my tonearm is mounted in such a way that I can slide it from roughly 285mm spindle to pivot to roughly 304mm spindle to pivot. I have a feeling that it should be mounted ~10-12mm farther away from the spindle. Is something wrong with me? Is something wrong with my tonearm? Am I going crazy? This whole experience makes me want to get a Technics SL-1200 where you just align the cartridge using the supplied jig, it hits the Stevenson alignment and you're golden.
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Tomcat1969
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« Reply #49 on: February 11, 2021, 11:27:50 PM » |
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My 3009 drove me mad too hence the conversion to a detachable headshell and a Bearwald alignment. I went down the same route as you with the printed one using SME data, an SME single point and even the Dr Feikert protractor. I also became quite frustrated.
Sorry for not offering a solution, but rest assured there's nothing wrong with you or the tonearm and nor are you going crazy.
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Peculiar Permali Platform PTP5 with Siens long bearing and 14" platter, 12"SUPATRAC Blackbird/London Decca or Bokrand Sonoro/SPU. Parks Puffin, B1 with Korg triode, 2 x Zerozone class D monoblocks, Tannoy Eaton speakers. Oh, and Nigels Speed Controller.
Billy
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flood2
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« Reply #50 on: February 12, 2021, 12:10:46 AM » |
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I now have an assortment of tools that are supposedly designed specifically for SME 3012 Series II and I still have no idea how to align it properly ![embarrassed](https://www.lencoheaven.net/forum/Smileys/yarex2/embarrassed.gif) I have a later SME one-point protractor which has its null point at 66mm from the spindle. It is impossible to align the tonearm using this tool, even with a slotted headshell. I have an original (old) SME alignment protractor with a single null point that is somewhere between 60 and 60.5mm. I assume it matches the "canonical" alignment (60.3mm inner null, 117mm outer null). I can only hit the null point if I slide the tonearm all the way back and slide the cartridge all the way back in its slots. It is impossible to hit the null point using the stock headshell. If I use the stock headshell with any of my cartridges, I end up missing the null point by several mm. I have an arc protractor which is generated using SME-specified values: 294mm spindle to pivot, 11mm overhang. The thing is, when my tonearm is at roughly 294mm from the spindle, it is absolutely impossible to get 11mm of overhang. This would require a headshell which is only ~3cm in length and such a thing doesn't exist. As I mentioned previously, my tonearm is mounted in such a way that I can slide it from roughly 285mm spindle to pivot to roughly 304mm spindle to pivot. I have a feeling that it should be mounted ~10-12mm farther away from the spindle. Is something wrong with me? Is something wrong with my tonearm? Am I going crazy? This whole experience makes me want to get a Technics SL-1200 where you just align the cartridge using the supplied jig, it hits the Stevenson alignment and you're golden. This does very much suggest that the mounting position of the arm base is too short/"incorrect" which is why there is insufficient room to set the nulls. The arc protractor won't work satisfactorily for the SME sliding base design - the only 2 parameters that are fixed are the headshell offset and the linear offset. The effective length and overhang will both change according to the cartridge dimensions - the effective length is not a specification but an approximation given the variation between cartridges for the cartridge mounting hole centre to tip distance. Even if you use a slotted headshell and fix the pivot/spindle distance, I very much doubt that you can measure this distance to the accuracy required to generate the arc (or the reverse). I suggest using the original SME jig to set an approximate pivot/spindle distance where you have enough adjustment room for the slots, then move to a 2 point protractor to actually set the alignment - a 2 point protractor is completely agnostic to the pivot/spindle distance. Just a minor point about the Technics alignment, it ISN'T the Stevenson 1B alignment as is commonly mis-stated on the internet. The null points are 58.8 and 113.5 based on a linear offset of 86.16mm. Stevenson 1B nulls are based on a linear offset of 88.64mm. IMO, the Technics alignment is the better Universal alignment for all 3 record sizes if you are a DJ and generally not playing at the outermost grooves. However, if you mainly play LPs, you may start to hear the limitations. If you wish to use an alternative alignment, I recommend using the Jelco HS20/25 headshells with adjustable azimuth and pay very close attention to setting the correct arm height because you will need to compensate for the resultant mismatch in the vertical bearing offset to the new offset.
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stratokaster83
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« Reply #51 on: February 12, 2021, 12:20:53 AM » |
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This does very much suggest that the mounting position of the arm base is too short/"incorrect" which is why there is insufficient room to set the nulls.
Yes it does, however I measured the distance from the center of the spindle to the center of the tonearm base and it is ~295mm which is even a tiny bit longer than 294mm specified by SME. And this is exactly why I am so bewildered.
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flood2
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« Reply #52 on: February 12, 2021, 08:21:14 AM » |
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Yes it does, however I measured the distance from the center of the spindle to the center of the tonearm base and it is ~295mm which is even a tiny bit longer than 294mm specified by SME. And this is exactly why I am so bewildered.
In which case, this suggests that the linear offset of the tonearm may not be 88.64mm but something else! Are you able to estimate the offset angle? From that, and the specified effective length we can calculate the linear offset and determine a matching set of null points
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« Reply #53 on: February 14, 2021, 10:43:27 AM » |
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I have an arc protractor which is generated using SME-specified values: 294mm spindle to pivot, 11mm overhang. The thing is, when my tonearm is at roughly 294mm from the spindle, it is absolutely impossible to get 11mm of overhang. This would require a headshell which is only ~3cm in length and such a thing doesn't exist.
As I mentioned previously, my tonearm is mounted in such a way that I can slide it from roughly 285mm spindle to pivot to roughly 304mm spindle to pivot. I have a feeling that it should be mounted ~10-12mm farther away from the spindle.
Is something wrong with me? Is something wrong with my tonearm? Am I going crazy?
Dear Pavel i have experienced very much the same, which is way I joined this conversation earlier. There is one thing I noticed though, which is probably why there is so much discussion on this tonearm: SME at one point states the distance from pivot to a point between the two holes for the cartridge screws being 11,58 Inch, therefore 294,1mm. So the distance from this point to the stylus has to be added, which is depending on the cartridge and therefore remains variable. With a Shure M95 for example, it measures 10mm. A Shure M75 though, has only has 7mm. My custom Denon DL103 (Alu Body) has 5mm. This is the reason, why SME went for the sliding base. According to Robert from Analog Tube Audio, who has restored my arm, there must have been several different geometries during lifetime of the SME 3012/II, whereby the later arms seem to have been shorter than the first ones with the split counterweight. The first SME 3012/I and the later SME 3012-R seemed also to have had deferring geometries. On top, is anybody really sure, that they are using a correct head shell, even if it is an original SME one? I know about variance in these. To make this story short, because of the above, I do not expect the protractor off the flea-bay to be correct. It's based on a fixed mounting distance of the tonearm, which is not applicable in this case. On top, there seems to have been variation in the arms itself, during their time of production. Sadly, hardly none of the arms nowadays have their original set-up instructions left. Even SME may have lost track on this.... For your comfort: The pivot of my arm is mounted at approx. 302 to 304 mm to the spindle of the turntable, depending on the cartridge I am using. Cheers Marco
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Marco
I use a Lenco 88 with SME 3009/II and 3012/II in an Acoustand Plinth, plus a Lenco B50 Electronics are all based on or including tubes - Tubes Rule!
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Tomcat1969
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« Reply #54 on: February 14, 2021, 11:00:22 AM » |
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This is a great thread! Very informative.
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Peculiar Permali Platform PTP5 with Siens long bearing and 14" platter, 12"SUPATRAC Blackbird/London Decca or Bokrand Sonoro/SPU. Parks Puffin, B1 with Korg triode, 2 x Zerozone class D monoblocks, Tannoy Eaton speakers. Oh, and Nigels Speed Controller.
Billy
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« Reply #55 on: February 14, 2021, 06:20:18 PM » |
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Correct headshell or not, the sliding base " linear offset" is all rubbish. If you take any of the old SME's the quoted distance is to the centre line of the mounting screws. Now lets take a Denon 103 for instance, then you need to add another 3/8" approx to find the true distance to the stylus! This alters the offset angle by about 1/2 a degree or there abouts. No amount of sliding about on an all be it handy base will make up for the angular error, and lets face it that is the whole raison detre for all the faff anyway! Forget the quoted distance. try to measure the actual distance. Then measure the pivot to spindle distance then use the Vinyl engine or some other calculator to realise the true offset angle for the real measurements obtained and the chosen alignment you want to achieve. This will be much closer to real life requirements for the actual pivot to stylus and pivot to spindle measurements. Its a fixed triangle and therefore has definitive angles related to a right angle triangle that no sliding base can overrule.
Andy
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Lynnot
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« Reply #56 on: February 14, 2021, 09:06:39 PM » |
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Or use a regular, slottet headshell.
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« Reply #57 on: February 14, 2021, 09:24:52 PM » |
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I imagine you could change the orientation by half a degree even in a non-slotted headshell?
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stratokaster83
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« Reply #58 on: February 15, 2021, 12:40:14 AM » |
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Dear Pavel
i have experienced very much the same, which is way I joined this conversation earlier. There is one thing I noticed though, which is probably why there is so much discussion on this tonearm: SME at one point states the distance from pivot to a point between the two holes for the cartridge screws being 11,58 Inch, therefore 294,1mm. So the distance from this point to the stylus has to be added, which is depending on the cartridge and therefore remains variable. With a Shure M95 for example, it measures 10mm. A Shure M75 though, has only has 7mm. My custom Denon DL103 (Alu Body) has 5mm. This is the reason, why SME went for the sliding base. According to Robert from Analog Tube Audio, who has restored my arm, there must have been several different geometries during lifetime of the SME 3012/II, whereby the later arms seem to have been shorter than the first ones with the split counterweight. The first SME 3012/I and the later SME 3012-R seemed also to have had deferring geometries. On top, is anybody really sure, that they are using a correct head shell, even if it is an original SME one? I know about variance in these.
To make this story short, because of the above, I do not expect the protractor off the flea-bay to be correct. It's based on a fixed mounting distance of the tonearm, which is not applicable in this case. On top, there seems to have been variation in the arms itself, during their time of production. Sadly, hardly none of the arms nowadays have their original set-up instructions left. Even SME may have lost track on this....
For your comfort: The pivot of my arm is mounted at approx. 302 to 304 mm to the spindle of the turntable, depending on the cartridge I am using.
Cheers Marco
Thank you Marco. I actually do have the original manual for my tonearm which simply shows how to use the 1-point protractor. Cheers, Pavel
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