Shelter 90X Tracking Force

My 2 cents. The Shelter's VTF requirment, like most cartridges, is temperature dependent. My 90X is mounted in an OL Illustrious arm and for ambient temps in the range of 68-70f I track at 1.99g. Higher temps require less tracking force. I use a trick I gleaned from Doug Deacon and use different weight o-rings slipped on the arm stubb behind the counter weight. The temerature lets me know which o-ring to use and I can repeatably fine tune the tracking force with out having to move the counterweight and measure the VTF.

Good trick, John / Doug ...

Can you imagine how much fun it is to exhibit an analog rig at CES, with the doors open to the morning air in Las Vegas in January?

It sure catches my attention.

Cheers,
Thom @ Galibier

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Thom,
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Great posts as usual / Thanks
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What would be your first choice for the best VTF scale that is available ?
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Rgds,
Larry
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Hi Larry,

The Durascale 100 made by MyWeigh has given me repeatable readings. You can Google for their website and link to online retailers.

The only calibrating tool I have for these is the manufacturer supplied weight.

Calibrating weights from two different MyWeigh models differed by some .08 grams for a 100 gram weight - a .08 percent consistency of the calibration "tool".

This weight variance seems good enough for our purposes, since we're concerned with repeatability more than we are with an absolute number. I don't think you care that my 1.87 is your 1.88 - especially since you need to work around the temperature in your room to establish your own norm.

Likely, a better calibrated 100 gram weight is readily available if this causes lost sleep.

The real challenge lies in measuring at record level, and here the price jumps considerably for a pre-configured solution. I'm working on having parts made for a small fitting to use with these Durascale 100's but will likely take a month or so before I get around to this.

The reason I'm using the Durascale 100 as opposed to the 50 is because the acrylic fitting comes in at about 75 grams and I need to be able to "Tare" this amount out.

Our mutual buddy Dmailer, builds up a platform to get the measuring surface of his scale to record level - without using a step-down fitting on the weighing surface.

This solution can likely work quite well with your Teres since your headshell is out in space. Pile stuff up under the scale by resting it on your tt shelf instead of on your platter. This could get a bit tricky with some 'tables. You'd definitely want this "stuff" you rest the scale on to be stable.

Cheers,
Thom @ Galibier

Pile stuff up under the scale by resting it on your tt shelf instead of on your platter.

I used to use our My-Weigh MX-50 that way, except instead of piling stuff UNDER the scale I built a tower that sat on top of the weighing platform. The little tray that comes with the MX-50 sat on top of the tower to provide a flat weighing surface at record height. This had the advantage of separating the magnetic scale from the cartridge.

What did I make the tower from? One sheet of copy paper. Cut to the right length, fold into a triangle for stability and Scotch tape together. The cost seemed reasonable and it worked fine.

Then Paul made a weighing drop-down step by folding a piece of brass strip he "sourced" from the local hobby shop. The cost was outrageous, about $.79, but it worked a bit better than the paper tower because it put the MX-50 in the middle of its range. Load cells perform more reliably near the middle of their range than at the extremes.

Larry, we sent you a spare brass strip quite a while ago. Have you made your weighing step yet? We want pix!