VTF measurments with a unipivot

Thanks Steve. Perhaps I should clarify a bit more. As you know, most scales do not allow taking measurements precisely at the record surface level. So if you measure the VTF higher than the surface, will it measure lower or higher than the actual VTF at the record surface? From what you said, assuming the tonearm is parallel, it'd be lower, but I've seen some posts here that seemed to suggest that the VTF is actually lower at the record surface than when measured higher and even a few millimeters can make a difference of tens of a gram.

Also, in the most recent issue of Stereophile, Fremer wrote an article discussing various unipivot designs and stated that whether the VTF will be higher or lower relative to where the measurement is taken depends on the center of gravity in relation to the pivot point. He lists three different types of unipivots, but his discussion is horribly lacking in my opinion. It is unclear to me what type the VPI arms are. Ignoring the types, I just wanted to clarify whether the VTF will increase or decrease at the record level if it's measured a few millimeters above the record surface.

Hdm and Captain Winters,
Thank you for your responses; this is exactly what I was looking for! My digital scale has the same design as the one in your link, Hdm, only is a cheaper version. It does seem to do a decent job with the exception of a negative reading as the cartridge approaches the dot. However, I get consistent readings both ways (I place the stylus on the scale and then turn it on; once I get a zero reading, I lift the tonearm).

Brf,
Yes, I agree with you that the final adjustments should be done by ear, but Lyra cartridges have a very specific VTF recommendation for optimal performance. So before I start adjusting, I'd like to know what 1.75 g sounds like and take it from there. To get the best sound out of my Delos might be as simple as making sure the VTF is set up correctly.

Thank you for your input, Raul. I think the "perfect" VTF in that sense is simply a VTF that optimizes the performance of the cartridge over the wide(st) range of recordings, similarly to the VTA. Jon Carr determined that for some of his cartridges, this is achieved with a VTF of 1.75 grams, and I trust his expertise. I find that the way I perceive sound varies from day to day depending on many factors so the by-ear method does not always work for me. I'm also more of a set-it-and-forget-it kind of guy. I'm not a "tweaker"; I want to spend my time listening to music, not analyzing the sound of every record.

Also, it seems to me that by your logic, you could never find a "perfect" (or perhaps "correct" would be a better word) VTF for a cartridge unless you'd be willing to adjust for every record, which is surely not true. There must be a VTF setting where any given cartridge performs best, whether it's a range or a pint point value, all else being equal. Again, if a designer of Jon Carr's caliber tells me it's 1.75 g, I listen. It may not be the way many audiophiles do it, but it has worked for me and my Delos so far.

I agree, Raul. Perhaps worthy of noting is the fact that the new Lyra cartridges have a much narrower VTF range then most cartridges on the market. Most cartridge manufacturers seem to suggest a range of 0.4 grams and up, whereas Lyra range is 0.1 gram, at least four times smaller. So not much to experiment with, and the middle of the range, as you suggest, is 1.75 g.