Developing A List Of Tonearm Candidates For A SOTA Turntable

@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.