Measuring VTF on a Clearaudio Concept

How much is "way off"? I would not think that .33" will make that much of a difference, depending on the length of the arm. You do need to worry about cheap digital scales having ferrous parts that will draw the magnets of a MC cart, creating large errors. Usually the ones with stainless steel platforms will be OK.

I have an Ortofon DS-3 and its a POS. Mine would never zero correctly and had large errors. I actually purchased 0.5 g, 1.0 g, and 3.0 g calibration weights to check accuracy of the scale. The inexpensive digital scales from AWS (MB-100) work quite well, and are non-magnetic.

(Assuming you don't have fine VTA adjust capability on your tonearm) you could retain your digital scale and, if there's room next to the platter, make a small shim/platform that raises the gauge(pad) to a suitable height (i.e. that matches the stylus when positioned on a 120g record). Chances are you'll have mostly 120g pressings but 150g can be chosen if you wish to average it.

The good thing about a separate platform is that it won't be as "fidgety" as a platter thereby risking damage to your cartridge should the cantilever be accidentally "reversed". Failing this you should ensure the platter is firmly blu-tacked or taped up to immobilise it when playing with scales (just to be on the safe side).

Hope this helps...

Moonglum has a good answer, but remember that playing a record is a dynamic adventure. As the arm goes up to the top of a warp, it weighs more than on the flat...providing you were careful about the setup to begin with. Also vtf affects vta which is constantly changing as the record is played. VTA, affects other parameters...the best we can hope for in turntable setup is that we get as close to perfection as we possibly can do...but all of life is like that. :)

Like SG says...just to complicate matters, most unipivots are intrinsically unstable when riding warps. This is perhaps one area where gimballed arms might justifiably claim to have a slight advantage.

(Except SMEs, perhaps, whose tapered armtube can collide with the warp halfway through a side with an impact like thunder.) ;^)

Don't replace your inexpensive scale. Just use it correctly to measure what you're trying to measure.

Like Moonglum, I long ago made a weighing step. My digital scale sits on top of the platter. The weighing step sits on the scale, hangs over the edge, then drops down to a flat step that's at record height. That's what the stylus rests on when I'm measuring downforce.

And yes... 0.33" will make a huge difference with many tonearms.

I made my weighing step by folding/bending a piece of 1" wide copper strip into shape, but any non-magnetic material will do. Cut up credit cards and glue the pieces together... it'll save money!

P.S. Whatever scale or doohickey you choose, don't get the idea it will tell you the optimal downforce for your cartridge. Only your ears can do that. A scale's only use is making sure you're in the ballpark (ie, within the recommended range for your cartridge).