VTF and VTA- Constant or not?

...the correct VTF in a given cartridge defines the correct position of the cantilever (= the coils in the magnetic field) towards the magnet(s) and that the correct SRA/VTA is always a matter of the position of the polished area of the stylus towards the grooved wall.

Dertonarm, your description is simple but precise!

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.

Dertonarm, according to these findings, do you imply in most cases the optimum range for a tonearm could be from perfect horizontal up to 14mm tail-down?

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.

Doug, exactly! When my MY Sonic Lab Ultra Eminent BC was new, it sounded best at ~2.1g. After 1.5 yr until now, the best VTF is somewhere at 1.6-1.7g. Not all cartridges behave this way, though.

Dan

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.

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.

Doug!!! 1.2gm for the Universe?
I seem to remember a post of yours saying anyone brave enough to go below 1.7gm is on his own?

OK...I'm going to adjust my DaVinci/Universe to negative VTA and 1.5gm to see if I agree?

Regards
Henry

Henry,

Most people believe I'm very much on my own. Why disappoint them? ;-)

Do remember that our cartridge reached this stage in small steps. We did not wake up one morning and ask, "What would happen if we dropped VTF from 1.70 to 1.20?".

Of course there's no reason to believe 1.50g or any other randomly selected number will be optimal. That's neither science nor craft nor even art, its guessing.

IME with 10-12 UNIverses, each one's VTF is best adjusted using the protocol I've posted before: find its mistracking point on very dynamic passages, work very slightly upwards from there by listening.

Have fun!
Doug

BTW, if you can play a UNIverse (or any cartridge) with "negative VTA", we'd all like to see photos. ;-)