Stylus force digital scales


Digital scales from Clearaudio and others range from $200-500. Amazon has 'em for $20. Why cant I use one of these instead and save big bucks?
tbromgard
cleeds,
Let's agree to disagree, once you have acknowledged the following:
(1) Our disagreement is NOT about the degree of difference in VTF caused by a warp or whatever.  I have written twice already that I agree the difference is "small" (if we're talking about LP thicknesses).  I thought we were arguing over your statement in response to someone else, to the effect that VTF would not change AT ALL when the stylus traverses a warp, because (you said) gravity is a constant, etc.  I of course agree that gravity is a constant, but you failed to take into account that raising the tonearm up above the horizontal, as happens when playing a warp, does change VTF, because it changes the geometry and introduces a force vector that is not directed downward, perpendicular to the LP surface.  That small force vector subtracts from the effect of gravity to pull the cartridge down on the LP, reducing the effective VTF.  And talk to Einstein or any other theoretical physicist, if you cannot abide thought experiments.  Based on the limits you want to set on logical arguments, we would still believe in a flat earth.

I notice now that you have changed your tune; you now say that the "thickness of an LP" has a "trivial" effect on VTF.  At least you agree that a thick vs thin LP or a warp would have SOME effect on VTF.  And I am telling you why it would.

(2) The bit about Dynamic VTF. You are confusing me with someone else (whom I respect) who commented that tonearms with dynamic VTF would be less subject to variation in VTF on warped LPs.  In fact, I think you're misquoting him, but go argue with that guy.
@lewm as I said in my last post my experience is that even scales with non magnetic pans suffer from magnetic interactions. I own several scales with such pans and all read differently than my all plastic options (cartridge man and rega) - and all read exactly the same with reference weights (which are not magnetic)
folkfreak, That's very interesting and a bit disconcerting.  Steel can contain some low concentration of iron, so that may be the problem. I will check the weigh pan of my digital scale with an actual magnet, to see if the magnet "likes" the weigh pan at all.  FWIW, the weigh pan on my digital scale is white-ish in color and looks like it may be ceramic, not metal at all, which I hope is the case.
@lewm it may not be an issue of interaction with the pan but an effect upon the mechanism itself, I guess you might know by seeing if bringing the cartridge close to a previously loaded pan reduced the measured weight?
The very expensive Rega scale does its job nicely and quickly. It always tares itself before weighting. The weight pan is a little dish so the actual measurement level is very close to record´s surface. Highly recommended for all vinyl lovers. Many thanks Folkfreak :)