Developing A List Of Tonearm Candidates For A SOTA Turntable

@neonknight : Thank you for your comments on the Agile. Good to hear that you like it. Being one of those benighted users who still changes VTA for varying record thickness, I’m curious about your thoughts on the VTA adjuster. In practice, does the calibrated dial lend itself to easy, frequent adjustment? What’s the actual process?

@audio_rd_uk : Glad you chimed in about your Agile. The same VTA questions to you. Also, did you have the chance to hear a 12-inch version during your forays to OL headquarters? If so, what sonic differences did you note? I’m considering it for the back position on my Technics SP10R, which needs a long arm in that spot.

@wrm57 To me the system works like Pete Riggle VTA adjuster but there is an extended grub screw to lock the VTA setting. Since the Sota armboard sits lower than the top of the plinth it isn't the most convenient system to use. On another table I am sure it is just fine. But there are more convenient systems like the Wheaton one. 

@neonknight Ah, I see. Is the grub screw adjusted with hex key? Using a ball-tipped hex key makes it easier with a recessed armboard, since you can insert it at an angle. My armboards are like that, and my Graham arms have a tiny grub screw to lock and unlock the post. The ball-tip makes it almost convenient.

@wrm57 Thatbis correct, with a hex key. Fairly easy to adjust, but not as good as a knob. But a SOTA has limited space on that island shaped arm board, so those arms with a VTA tower architecture just do not fit. But performance is the real deciding factor, and the Agile is a capable arm and that is what works for me. I will say it is substantial, and SOTA has to go to work hard at making an arm board that allows for this arm to work wither tables. Quite a synergistic pairing!

@neonknight re your VTA question.  In summary if you / anyone doesn't want to read the 'process' below. My MC Diamond is not set at what would be above the specified 23 deg to achieve a 90 deg diamond angle, but at nearer 25 to achieve closer to the 92 deg angle that Ortofon state is likely to be optimal this is relative for the 'typical' 180g vinyl it is fed.  It is for the reasons below presently not adjusted from that.   

I am not at all surprised you are very happy with the Agile and feel there is no need to pursue anything else.  Are there things I could suggest to get the best from it, possibly, will music sound wonderful without them? absolutely.

Based on looking at this with Mark Baker and also noting the words of Michael Fremer (who was shall we say somewhat blunt in his description of those who adjust for every record) I did the following test and adjustment in late 2022 after I got my 45rpm UHQR of Kind of Blue (KOB) and noted how relatively 'thick' it was. Noting my RD is because I work in R&D for both audio and some other industries and why I have 'measurement equipment'.

I took several of the thinnest records I have (generally 80's pressings) and the thickest, which is KOB and measured the thickness of the lead in edge with a micrometer and also measured the distance in height of that edge in the turntable itself using a fixed position dial gauge and manoeuvring the record into place without moving the dial.

I did this initially on an OL Sovereign which helped because I attached the magnetic gauge base to the left one of its large mass feet (with a cloth between). I also measured what I would say is its "main feed" of 180gram vinyl. Between each VTA I did check tracking force and had I gone from thinnest to thickest I would to keep to the exact force have had to make a small adjustment to the balance. As force had been set previously at the setting for 180g's there was less than a 0.1g variation but approx only 0.03 to 0.04 deviation from 180 setting to bottom or top. 
First I set VTA (spec says 23 but actually it should be 24.75 to 25 on mine) so that the stylus rake angle was 'optimal' (92 deg) for the thinnest and played them and I admit I didn't try the UHQR at that setting, but did try some 180g which was then at a more acute stylus angle than optimum.
I then set VTA for the stylus angle for the mean height for the 180g and tried the thinner records with the thus 'too large' angle and 180g's at correct. I found that the 180's sounded better than they had with the too acute angle and whilst there was a minor relative quietening of some hi-hat relative to snare / bass on the thinner records it was very minor and only on records I had specifically chosen to test that. I have a 'thin' 33 and a 33rpm and 45rpm 180g version of Time Out and there was less differential between the 'thin' record played at is optimum to it played at the 180 optimum than there was difference between the 33 and 45 version.  Same with my Dusty S, Look of love 33/45 test record.  Playing the 'thick' UHQR and a 180g borrowed kind of blue at the '180 setting' the UHQR was significantly superior and I then took the setting to the UHQR and tested these two again. The UHQR improved a little,(and sorry I didn't record the 'turns' on the VTA partly because when I got my Agile about Oct 2021 they hadn't put the lines on it. I do have them on the update arm ) but it hadn't moved that far, it was certainly less than the movement from 'thin' to 180. 

What I then did, without the now 'lines' was I went back to the 180 setting and 'tweaked' it up towards 'high' until I heard what I thought was a 'slight' reduction in the hi-hat on the 45rpm of time-out.  Then went back one 'tweak' which probably was about a 'division'. I then replayed the UHQR from that point and replayed it at its optimum and it was extremely difficult to tell the difference with less than a minute between playing. I did this again for one 'tweak' lower to 180 setting and it was the same.  So after the testing some 'thinner', that are probably 1 in 20 to 1 in 50 of what is played and I decided to leave it at that point. I concluded that whilst some decks may be more or less susceptible and some ears may be better than mine, Michael Fremer's comment whilst 'harsh' in its description. Was for my system in late 2022 applicable.

When I got my upgrades in Sept 2023 because I fortunately live 3 miles from Origin Live they came up for a trial of the deck on my system, so Mark's son Luke Baker originally set my VTA.  I repeated the above and mine is set 1/4 turn above what is supposed to be the ideal angle for my stylus but on a blown up microscope picture this is less than 1/4 of a degree high and TBH I haven't actually repeated that measurement when KOB is on it.  But it sounds better than it did before and better than the 180g version does on this set-up.  I haven't repeated the above test even though I have improved transparency in other parts of the system simply because when I go in there now I just want to listen. 

My conclusion is, if adjustment each time works for you, doesn't 'annoy you' and you hear a difference, then have a L,M,H setting you can easily move to* then why not, but see if you do also have to adjust tracking mass because you are effectively altering the horizontal (and thus the gravity acting) distance from the pivot to the tip of the diamond, so would you want to be altering that as well? And is that also what some are hearing as part of the difference? I note on that I have the Ortofon DS-3 gauge because when trying those with the design of the Project Measure-it I found that the magnetic properties of my quite heavy Ortofon MC Diamond cartridge where pre-altering the gauge reading before the stylus touched and other (far more expensive) borrowed scales showed they were consequently less accurate for my cartridge and the DS-3 were "within an acceptable margin" that was far less than the prescribed range, whilst the variation on the others was taking a good percentage of the range and a gauge's capability should be minimum 10x more accurate than the process which you are measuring.  So I doubt I would want to be measuring / adjusting both and if it was that much better,  I think I would 'schedule' thick and thin sessions. 

But for now both on the Sovereign-Agile and the other OL combinations I have been very happy with a stylus set at approx '180g' setting plus just under 1/4 turn which I suspect (noting it takes significant time to set the macro and microscope up to view this) is probably a stylus angle between 91.8 and 92.1 The latter of which seems to be what Ortofon thinks is the theoretical (and probably empirically tested) ideal.  So on UHQR I am probably at 91.3-91.5 which is going to be closer than most will be to Ortofon's 'optimum', because they quite likely set to 23 deg as that is what it says in the Specs.

*Your question has prompted me to re-do the test in the next month or two with a view to seeing if there is now enough difference given the improved transparency of my system. 

@neonknight  P.S. I note you had used a Verismo before you got the Agile and this has the same Multi Wall Carbon Nanotube technology (MWCNT), developed on the Verismo. They now use this on the MC Diamond which I have on my latest OL Deck with the older MC Anna Diamond being the one I originally tested above and having the less sophisticated suspension material. That being based on the fact that all else being equal the Diamond was significantly better than the Anna Diamond.  On a quick look I cannot see Ortofon noting on either the Verismo or the Diamond the "23 degrees = 90" though "92.1 being the potential optimal" thus requiring nearer 25 degree VTA.

Whether that is because they do not think the 92.1 deg is applicable to the MWCNT I do not as yet know, perhaps there is a reference elsewhere.   I just wanted to note this because when I changed to the MC Diamond from the Anna Diamond, I just checked the quoted spec was the same swapped, tested force and played with an immediate improvement.

I will see if I can find anymore references on this 23/90 deg vs 25/92.1 deg in case this has altered with the change in suspension material.

But if it is up to 2 deg range 90-92.1 for finding the 'optimal'  also that approx 1mm of height adjustment at the pivot is 0.25 degree at the stylus then my adjustments above for 180g to UHQR were no more than 0.5 degree within the MC Anna Diamonds quoted at 2 deg range.       

@audio_rd_uk : Thank you for your extensive comments on VTA, which I think were directed at me rather than @neonknight, since I opened the can of well-worn worms on adjusting VTA by asking about the dial on the Agile. I certainly appreciate the rigor of your analysis, but I do take issue with one conclusion:

My conclusion is, if adjustment each time works for you, doesn’t ’annoy you’ and you hear a difference, then have a L,M,H setting you can easily move to* then why not, but see if you do also have to adjust tracking mass because you are effectively altering the horizontal (and thus the gravity acting) distance from the pivot to the tip of the diamond, so would you want to be altering that as well?

This describes me pretty well: for each of my 7 tonearms, I have well-established presets in mind for standard LP weights, which approximately correspond to varying thicknesses. It’s easy to move between them per LP to maintain, for example, a level tonearm (which for argument’s sake only I will posit as ideal). So, is it not true that, if you set up all parameters with a level tonearm, maintaining a level tonearm by adjusting VTA actually retains "the horizontal (and thus the gravity acting) distance from the pivot to the tip of the diamond," and therefore the "tracking mass"? And in fact, not adjusting for record thickness would alter these parameters?

I’ve heard and read all the arguments by Fremer and other lovely experts as to why it’s impossible to hear minor variations from 92 degrees SRA, and the logic is compelling. I’ve tried and tried not to hear them with all my tonerams, setting VTA for, let’s say, a 160g LP and leaving it alone. It always sounds worse, and in predictable ways, for LPs of other thicknesses. Cue @mijostyn to tell me why I’m suffering from confirmation bias self-delusion :-). It’s an old specter that I did not intend to conjure again. I really only wanted to know more about the VTA mechanism on the Agile, which seems like it would suit my peculiar need.

@wrm57  Here I am. I was taking a nap. 

The problem is that most people have no idea where they are actually starting. The contact line has to start at 92 degrees. Even with a stabilized high power USB microscope this can be hard to see. In many styluses the contact line is not symmetrically in the center of the stylus. In the replicant 100 the contact line is parallel to the rear face. One has to know where the contact line is for the stylus they are using and measure from that. How one determines 92 degrees is with the stylus on the record at the correct VTF. One has to use a transparent protractor with 92 degrees scribed in very fine lines behind the stylus. If one is starting at say 95 degrees a fraction of a degree might make a difference. If you are truly starting at 92 degrees then a degree one way or the other will not make any difference. To prove this to yourself set the contact line at 92 degrees then have a friend change VTA or not and record your response for each position. I promise you will be amazed at the results. 

The Agile's mechanism is typical British simplicity and like the Schroder has a scale so you can return to previous positions accurately. It might be a bit fiddly in the Sota's tonearm well and I would not recommend trying to adjust it on the fly. 

I set VTA by ear using a known sample of records. My ears are more accurate than my eyes and I believe this would be true for most.

I sample thick and thin and from that testing I know exactly how must to adjust - for convenience I divide my collection into 180g and other ( thin ). Therefore I only run 2 settings.

Please note that you are not "adjusting VTA" for the thickness of records, you are trying to correct the VTA for the variation in thickness of each record.

Some early records are known to have been cut at odd angles, for these you either can ignore or again adjust by ear.

WARNING

Firstly, even though many of my tonearms have true VTA on the fly, I always lift the stylus off the record. I never adjust whilst playing. David Fletcher of Sumiko recommended this to me many years ago. Most VTA adjusters are quite brutal on the cantilever suspension and stylus if left playing.

Secondly, The Origin Live Agile has a fundamental flaw in that it has non offset bearings. This means that every time you adjust VTA on the Origin Live the azimuth changes. Another example of this are vintage arms like the Fidelity Research FR64S where I can hear the soundstage moving around from left to right and vice versa as VTA is adjusted

Note that if you are correcting VTA for a thicker record ( bringing the stylus back to the same angel as for a thinner record ), then the azimuth does not change.

Personally I could not live with an arm with non offset bearings for this reason because I hear quite large differences with dialling in VTA - I’ve measured a thou of an inch that I can hear significant differences.

@dover, that's really interesting. Thank you.

@mijostyn, it's hard to believe you ever nap!

@dover 

"Please note that you are not "adjusting VTA" for the thickness of records, you are trying to correct the VTA for the variation in thickness of each record."

There is enough question of the need for adjustment / correction or at least the amount of adjustment / correction, lets not split hairs over two statements which amount to the same thing. You are adjusting the VTA from what it was because of  change in the thickness of the record you want to play.  But you are only correcting it if you are without doubt that the angle you are setting it too is exactly the correct one. 

@wrm57  Actually no I was responding to @neonknight question of what I did on VTA.  Which I was giving a why rather than just an answer.  With regard to your point on horizontal and noting the caveat yes if the angle of the arm is set to the same each time then the horizontal distance would not vary.  But, with a two or three L,M,H as I described it then there will still be variation to the horizontal from LL to LH, LM to HM and LH to HH. So my point was only there is still going to be a range of tracking forces if using a 2/3 point setting without adjustment to the counter balance. Is it a variation that is enough to make a difference. It sounds as if if it would for some be far too much as they can hear an angle difference of 0.004 degrees.  Which when I have not seen a spec that reads below 0.1 of a degree is impressive to hear significant differences.

@wrm57 Even robots have to recharge their batteries once in a while:-)

Please pardon my horrendous mistake. I was not referring to VTA. I was referring to SRA. Stylus rake angle is far more specific than vertical tracking angle. VTA depends on the stylus being mounted perfectly which is not the case in, I would guess, 75% of the cartridges. It is like setting SRA by making the tonearm parallel to the record. These methods of setting SRA are easier to see, but there are simple magnifiers that will get you close enough as long as you know where the contact line is. The magnifier that comes with the SmarTractor is perfect. They should sell it separately.   

@dover That is a very valid point. I should have noticed that. A tonearm with vertical bearings that are not perpendicular to the offset angle is a deal killer, the reason being that azimuth now changes with elevation, over warps and with different record thicknesses and as far as I know there is no down side to offsetting the vertical bearing

Your ears are only going to notice a difference in SRA when you are already far off the mark. While it is true that some old records have odd angles, they are also very deficient in sound quality for other reasons and are of historic value only. I would not be concerned with trying to optimize them. If you set your SRA to 92 degrees with the stylus on 150 gram record you will be able to go a degree in either direction without noticing a significant change in sound quality. This is the opinion of many seasoned audiophiles. The problem is setting the contact line to 92 degrees is not so easy. However, fishing around for the right SRA by ear is a PITA and very unlikely to be accurate. 

This line of discussion regarding offset and VTA is at times amusing, and at others tiring at best. I was listening to vinyl last night, and what i find is the SOTA with Agile arm is not only the best table and arm combination I have, it is satisfying in ways that other tables never have been. I had been through a journey of exploration over the last 15 years and have owned the SP10, DP75, Brinkman Bardo, Well Tempered Reference, Amazon Referenz, Galibier Serac, VPI Prime, and a number of arms. I am sure there are a few tables I missed in there, it is early in the morning here. 

What I hear with the Cosmos and Origin Live combination is fundamentally superior in every aspect of music reproduction. Some times you hear the sound you connect with and say this is it. I am at that point with this arm and table combination. Now the Proteus sounds very nice on the Scheu/Schroder combo I have, but it does not approach the beauty it posseses on the SOTA/Agile. I can listen to this all weekend in pure bliss. There combination has it all, richness, texture, subtle detail, inflection, spaciousness, solidity, there is nothing wanting of it that needs...nothing that needs to be a little bit better. So with this table I am stopping here, although I am curious about how the Verismo would sound on it. But to be honest, the Verismo on the Scheu/Schroder comes in second place, so I am not eager to move the cartridge over. I prefer to enjoy the beauty of what is in front of me. 

You can discuss offset bearings, variations in VTA, how it affects overhang and tracking force till the cows come home. But when I sit down and listen all of it becomes just outside noise that does nothing to distract me. The music captivates me and that is the specification and design element that matters to me the most. This is a lovely lovely table and arm. 

@audio_rd_uk, my mistake. I appreciate the clarification on slight variances.

@neonknight, great to hear how satisfying this new set up is. That’s what we’re all after.

@wrm57 I apologise I hadn't answered your question regarding 12" OL Arms.  Yes I have and in fact I do have a 12" Enterprise arm, as when I bought the Sovereign it had that and the 12" Arm board, which fortunately for me is one you can swap over between a Resolution and Sovereign.   When I got the Sovereign and was already ordering the Agile from OL and had specified 9.5", Mark was at the time working on upgrades to Voyager, the Renown arm and he platter modifications and was at that point leaning himself towards 12" being preferable. So  I did contemplate going for the Agile in 12".  The reason I didn't was that when I tried the Enterprise it was clearly several steps above the Encounter arm I'd originally got when I bought the resolution. It was great with ballads, but if anything it felt/sounded like the result was 'dampening' perhaps 'too smooth' on fast percussive tracks. Further discussion with Mark at the point when he was developing the Voyager-S platter from which some of the Strata mat technology trickled down he was by this time last year considering that the upgrades to the turntable were leaning towards a 9.5" having the best balance overall.  That is what I have gone with on my upgrades and been very happy.  You can see what is my turntable on the videos (and actually also my Whest phonostage) on the  https://www.youtube.com/watch?v=7O9i5t0aGvg video of UK HiFi show 2023 at 9 min 37 Sec (sorry couldn't find an engl.   I do note that though the TT  sounded very good, that OL's 2023 exhibition rig of the speakers shown and sub can truly do even a Calypso and Silver / Onyx arm combo justice. Let alone a Sovereign / Agile, or Voyager/Renown.  I will find out tomorrow Fri 20th Sept whether they have upgraded that for 2024.  I will report back. 

@audio_rd_uk, thanks for following up on the 12-in Agile. Your rig looks sharp in the vid. So it seems you found the 12 to be slightly more relaxed and less dynamic that the 9.5, which is not unusual. I have 12 and 9 Graham Phantoms (III and Supreme, respectively) on the same turntable and that pretty much describes the difference in their sonic profiles. BTW, I recently adopted the OL Strata mat on this turntable. It's excellent, and I say that as someone with an embarrassing number of mats in the closet.

When the TT > Tonearm > Cart' are seemingly performing out in front of other permutations trialed or wed to. The introduction of using Platter Mats in a variety of types can then become another method to help really hone the end sound to ones preference.

I do this with a large selection of owned Mats and have found my go to mats. It s also quite a reveal how adding different spindle weights in conjunction with a Mat can enhance the qualities the Mat has shown as being able to add discernible improvements.

This line of discussion regarding offset and VTA is at times amusing, and at others tiring at best. I was listening to vinyl last night, and what i find is the SOTA with Agile arm is not only the best table and arm combination I have, it is satisfying in ways that other tables never have been. I had been through a journey of exploration over the last 15 years and have owned the SP10, DP75, Brinkman Bardo, Well Tempered Reference, Amazon Referenz, Galibier Serac, VPI Prime, and a number of arms. I am sure there are a few tables I missed in there, it is early in the morning here. 

@neonknight  This is what it's all about. We can (and do) go down philosophical back-holes pertaining to mechanical & electrical component design, but the "conclusions" often have little bearing on the pleasure we derive from a system. High-end vinyl playback is rife with patterns of solving the wrong problem, or a problem that doesn't really matter. It's human nature.

For sure, your SOTA does a great job addressing things that actually matter, with a minimal of the fantasy elements. Sounds like your new arm is a super match for it too. Congrats on your newfound pleasure machine!

@mulveling and ​​​​@neonknight I agree on VTA. As above I am in the ’club of’ find an optimal for what (thickness) you play most, set L/R balance for that VTA (I ultimately use a l/r balance record for that to also take into account anti-skate influence) and then enjoy.  After 42 years working in R&D I only pursue and fix real problems.

@wrm57 OL were at Ascot on Friday and as you can see at 3:11 https://www.youtube.com/watch?v=djDomUrQkEs using the Sovereign-S (which like the Voyager effectively has a ’strata’ matt built in) and Agile arm through their Discovery stage and a sugden amp into DeVore’s this year and a multi speaker sub-they modified with hypex amps. Sugden aside I am still not sure the rest of that set up allows the full capability of the deck through. We will be comparing through my two systems in 3-4 weeks. Though setting up in demo rooms is always a bit of a trial especially when they have as much glass as in the Ascot rooms.

After 42 years working in R&D I only pursue and fix real problems.

Are you saying that incorrect VTA is not a real problem.

If you believe that I would suggest your optimum cartridge would be something with a conical or spherical stylus.

@dover No, as I think you know, I did not make that statement.  

I was responding to the point made by the persons I quoted (who were I think a little fatigued with the to and fro on methods) that the reason I had explained my method in detail was because I wanted to find a setting that would satisfy me as the "good enough" setting and on my system "good enough" sounds better than systems I have heard at several manufacturers R&D facilities.  But also notwithstanding the issues of show set ups.  Close to systems with the same level of source I have but that have 3-5 times more expensive speakers at the Ascot HiFi show (such as Wilson Chronos) where I am fortunate to be able to go on press / VIP day and listen in relatively quiet rooms.

But since you brought it up, what you seem to either not be appreciating, or perhaps you are just not voicing in your thoughts, because it contradicts the 'spot on VTA for each record'. The point I made regarding 'fixing' was regarding the magnitude of and the full range of factors influencing the "incorrectness"  / the proportion of this that can actually be corrected through adjustment of VTA in order to set SRA and consequently the potential for that to impact the deviance this would have from 'total' enjoyment of the individual record. 

Because you are noting VTA (fundamentally SRA) in isolation would actually need to combine this with the other factors that alter the 0.004 degree SRA accuracy requirement you noted to be significant to you. But there are other factors you typically cannot control (and certainly not through the VTA) that vary the resultant SRA you have set by orders of magnitude 10 to 20 (+/- 5 to 10) times. What is more that variation is going on throughout the record.

What I sought was to establish was whether, to my ears, the adjustment from "one position" set to work with the majority of vinyl thickness that I play to what would be the true optimal for transducing the signal as close to the input signal. Not just true to the cutting head but removing that angular variation, etc, of different production processes to achieve the "original" in every case.

I explained my process, but for your 0.004 degree accurate SRA, what I haven't heard is whether you set this for the low, middle or high of the dynamic range of the track?  Because whichever it is will make a difference (as a function combined with  tracking force and whether we are talking 33 1/3 or 45) to the variation in contact angle due to the upward force component of quiet and loud passages. I did take this into account with my "one" setting as I tried a variety of quiet ballards to dynamic rock.  But for your 1/1000" do you listen to the whole track adjusting as you go?, pick a particular passage? If so high, low or medium?   

Then we have warped records.  You may have none, but as the typically quoted standard for 'warp' is that there must be "no interruption to continuous play" and for example eccentricity tolerance is 0.2mm.  Lets take half that 0.1mm because I certainly know I have records that play with no discernable issue that have variation above that.

A 0.1mm adjustment to the 'opposite' of the triangle makes a comparative variation of 0.023 degrees for a 9.5" / 241mm arm.  That is 3.93 times the amount of SRA / VTA variation of the 1/1000" / 0.004 degrees you hear.

In fact to get to a warp variation equivalent to the 0.1 degree resolution specification that the cartridge manufacturers quote would mean just under a +/- 0.25mm variation from a nominal neutral surface. The 0.5mm range giving a angle variation of 0.11 degrees. So given I know I also have records with a 0.25mm deviation. Which means even if I set them to the exact spec angle or chose that by ear for a noticeable characteristic. Over the record that SRA , , that is almost 20 times the variation in SRA you can hear.

So even on your records with less than +/-0.05mm variation from neutral surface, you are setting by ear, so you cannot be sure to be adjusting for the nominal.  That said of course the measurement you 'desire' being the measurement you set by is you taking that 4 to 20 times the SRA variation that you stated you are setting to when you "on balance" decide that is the best setting for that record.

So are you doing that on a particular tonal or dynamic characteristic of a section of that record?  If you do, then do you set the SRA to the same the next time you put that record on?  Or do you do the adjustment again?

Because not only does your record have surface variation, so does your platter. So if you have 0.1mm variation on the platter and 0.1mm variation on the record in one orientation these may cancel, in another they could double.   So my point is, when you think you are listening to a SRA/VTA that is set to your quote of your audibly discernable 0.004 degrees.  You are likely to be listening to something that is typically varying per revolution by 4 to 10 times the accuracy to which you believe you are setting it.

So when I say "I only pursue and fix real problems" first I don't want to adjust it every time to believe I am correcting an error that even if I used one increment on the VTA 'dial' which on mine is 30 degrees vs approx 10 degrees rotation for 1/1000" on a 1 mm pitch thread. Then I (or anybody else) would still be adjusting for something where there is at least 1 to 5 times that amount of variation in the warp of the record and what I know to be a 0.07mm variation (+0.4/-0.3 to the mean) in the surface of my platter.

Those amounts combined are approaching 50% of the variation due to the min to max thickness of most of what I play. So whilst of course these variations exist as an additional stacked tolerance to the variation in warp and platter etc,.  But if I set individual SRA via VTA to an aural characteristic, to be repeatable I would also have to note a reference of label orientation to a reference mark on the platter so as not to alter the relative peaks and troughs of the setting that I considered "the one". 

Even then the record and platter tolerances will not be varying by less 5 to 10 times of your quoted 1/1000th / 0.004 degree hearing capability. 

So adjusting VTA is only removing part of the 'problem' and to fix what I could I would (and have) attempting to remove / minimise the 'constant' variation in the platter which I note somebody who has undertaken around 30 years more experimentation in this area than I have and whom I trust to make £50k turntables and £35k+ arms tells me 0.25mm clocked platter makes no difference. The surface variation in the record cannot be adjusted (without a 'flatter' copy and only by referencing rotational position to the platter can it be said to be deviating but in a repeatable manner.

Consequently, both for this hypothesis and the empirical results that (once I had removed the 'extremes' of the problem through the method previously noted) I heard little improvement on adjustment for the majority of what I listen to, for the simple reason that the other factors are altering SRA to multiples of the degree that you consider to be the 1/1000th 'increment' threshold for VTA.   

Thus I have one setting and if I were to every move from that it would be to have one for 'thicker' and one for 'thinner' because for the actual system variations above I cannot constrain SRA to hold within 0.004 of a degree. 

Note that in my profession, apart from dealing with some of the best hifi source manufacturers in the world, I also deal both with systems that have up to 12 billion, billion setup permutations. But also analysis of manufacturing systems where the accuracy requirement of the manufacturing end effector must achieve a better than 4 nanometre accuracy. Which to achieve requires a manufacturing facility with foundations that for a single storey building have twice the steel reinforced concrete of the Burj Khalifa, [which I also did some analysis for]. When considering this, one has to take into account EVERY factor impacting positional and vibrational contributors to the FMEA in magnitude importance.  Just as I do in addressing the real problems in the factors impacting my hobbies.   

With regard to your last point. Thanks for your "advice" but I am extremely happy with the cartridge and I am more than capable of making my own calculations, analysis and decisions on them. When I do replace or refurb, my analysis will again take into account and prioritise scientifically all the factors that actually impact its performance. 

Dear @audio_rd_uk  :  I have not your knowlege levels and skills, I'm a mere "mortal ".

" to be repeatable I would also have to note a reference of label orientation to a reference mark on the platter so as not to alter the relative peaks and troughs of the setting that I considered "the one".  "

I did it in my comparison tests whole proccess with the LP tracks choosedfor those tests/comparisons and I did it only with those LPs and I did it many years ago when a gentleman in Agon commented about and I did it and made comparisons by listening changing the LP label positions and certainly we can aware of the sounds changes.

Yes,all is through my ears and today I need to revamp about because it makes an audible differences.. Thank's to posted.

R.

Would anyone be able to offer an informed opinion on whether the Fidelity Research FR-64S arm would work on a SOTA Star Sapphire?

@rauliruegas   No 'immortals' here, simply applying engineering rigour in consideration to all the contributing factors, especially when there are those that outweigh direct VTA/SRA adjustment in their quantum.

I had just incorporated it into my consideration because when I get a turntable I have a laser test and then if required a dial test for quantum. But I am unsurprised to find that others had already considered the warp / platter peak to trough orientation and found it made, as one would expect a difference being close to / higher in quantum than the resolution of the cartridge manufacturers specification.   

My follow up question would be, given you heard differences in those you tested.  Did the quantum of the variation persuade you to expand your test set and incorporate the "record to patter warp matching" in your daily playing alongside SRA if you adjust.   Or do you have a 'compromise' optimum for your normal range as I do?