VTF and VTA- Constant or not?

What would happen to the data on your post-it notes if you changed arm, cartridge, or table?
This thought has always kept me from adopting a similar system.

Quite right, Tom. Each data point is rendered obsolete by such changes, and by some others too. Our belt and battery improvements also resulted in small arm height changes, which of course I've recorded. The post-it notes on the LP's with the lengthiest data trails have about a dozen height numbers (and counting!).

However, and importantly, "obsolete" does not imply "useless". Such changes in optimal arm height are:
1) accurately cumulative with each other, and
2) consistent across all LP's.
IOW, if a new cart needs the TriPlanar's height to be 2.57 turns higher, and a subsequent change needs the arm .10 lower, I can play an LP that was last played before those two changes by moving the arm 2.57 - .10 = 2.47 higher than the last data point on that LP. All I need is a master list of height changes and an identifier next to the last data point on the LP note, so I know the currency of its last data point. Once I dial it in precisely (by listening) I record an updated point on that LP.

Even if I bring out an LP I haven't played for several years (and multiple equipment changes ago) I just add up the height adjustments since the last data point on that LP. Voila! I've just dialed in arm height on an LP last played several "systems" ago. This typically gets us within .05 or .10 on the TP's height scale, in mere seconds. Fine-tuning the precise new setting (which we record to the nearest ~.01) can be done whilst enjoying the music.

Record keeping sounds boring, but it eases the optimization of our playing and listening experience so much that I wouldn't give it up. Paul is fantastically sensitive to this adjustment (among others) so "close counts" is not an option for us. We actually chose the TP over a Schroeder Ref in 2004 primarily because we foresaw the value of this and the Schroeder lacks a height scale. (The TP was also $2K cheaper, but I've probably spent that in post-it notes - LOL.)

I'm sure it sounds uber-OCD, but Dan_Ed, Swampwalker, Nick Doshi, Raul and others have watched me do it and heard the results. I think they'd attest to how simple and effective it is. Of course they still don't bother with it themselves, so take that FWIW! ;-)

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Relative to what Dertonarm just (correctly) posted, all the above is contingent on playing your cartridge at absolutely optimal VTF (to the nearest .01g at least, we adjust much more finely than that - every day). Most cartridge suspensions soften with age and use, so VTF needs to be reduced accordingly. When our current UNIverse was new it needed ~1.70g. Today (2+ years later) it plays optimally (better in fact) at ~1.20g. That is not a typo.

If you don't do this, everything I wrote about arm height/SRA optimization is useless.

Plug 'n' play? Not quite!

Back in the late 1980ies and early 1990ies the collectors of vintage original vinyl (most notably the RCA LSC, Mercury SR, DECCA SXL and HMV ASD and SAX series) from a loose "circle" (most of them US-based). These gentlemen (and one lady...) did fairly early discover that there is a certain "angle" with the cutting laces in the various record companies. So there was something like a "chart" - were you could literally read down the VTA settings for a SXL, LSC, SR, ASD etc.
It eased up things quite a bit. The relative settings always were the same - no matter whether you use a 9" or 12" tonearm - just the relative distances changed according to the effective length of the specific tonearm.
I do not want to go into detail with this, but I can give you the two cornerstones of the chart: - Ortofon/OPUS3 have the highest required setting - i.e. the tonearm almost horizontal. Mercury SR is the deepest. About 14 mm down with the tail with a 10" tonearm.
Everything else (read: all other record companies LPs between 1958 and 1984) fall between these two extremes.
Give it a try.

Dan,

Since record company cutting head VTA's are known to have varied from a low of around 15 degrees to 20 or even 22 degrees, Dertonarm's suggested range seems reasonable.

I haven't gone that far myself, but I can confirm that there is great consistency within each record label, especially with records from the same plant.

Our first data point for every LP, recorded when it's cleaned, is the LP's weight in grams (a proxy for thickness). The LP's never been played by me so choosing an initial arm height might be a guess, except that I probably have a similar weight LP on the same label somewhere (I also have a list like Dertonarm's, though self generated and a bit half-assed). It's quick and easy to find a similar LP and calculate a starting arm height, adjusting as necessary if the new one is heavier or lighter.

This usually (90%) gets us VERY close to the optimal height for the new LP on the first spin. A little more record keeping, a lot more time saved.

Agree not all carts soften, it depends on the elastomers of course. Consult your favorite chemical scientist for details. ;-)

Doug

Dan, yes - horizontal level and from that point up to 14 mm down. With a 10" tonearm. Its slightly less with a 9" and a bit more (which isn'T possible with all cartridges/12" tonearms, since under certain conditions (small cartridge body, little height of cartridge body) the armtube touches the platter when you go that far down.
I mentioned this as a general "guideline" only.
Everyone will find his/her own "chart".
VTA on the fly makes this nor really a joy to find out, but eases things considerably. The change in effective length due to change of tonearm height is neglected here (never thought I would use the phrase ever regarding tonearm geometry ...) - it is too small to be corrected by hand at all. Much more important to the sound performance is to have the VTA groove-compliant.
And yes - some suspension do give in with age - some never.
My 28 year old FR-7fsp. still works with the very same VTF as in 1982. Fitted with its 5th stylus now, but same compliance. 80+ µm trackability with its lower limit optimum VTF set.
Certainly not the rule but maybe one of the very few exceptions in high-end cartridge history.
Cheers,
D.