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A weighty conundrum

I have recently encountered a problem with setting my tonearm pressure. I have 2 digital scales to confirm proper function with. The first is a Saga mini digital scale that has a weight spread of 0.1g to 350g. It's a flat scale with a metallic plate surface. The second is an arm load meter (no brand name). It too has a metallic plate with a white circular area center and a black dot in the middle. This model has a range of 0.1g, but only up to 5.0g. Both are calibrated with a 5g weight. Both check dead on with the 5g weight. I'm weighing the tone arm pressure on a Denon DP-47F direct drive table with a 2M Black Ortofon cartridge. The down and dirty Saga scale reads 1.6-1.7g. However the arm load meter (with newly replaced batteries) now reads 3+g. When I set it to the recommended stylus pressure I have to move the counterbalance weight almost out to the end of the arm. When I do this, the smarter than me automatic turntable won't even start. I'm flummoxed. Any ideas out there would be much appreciated. Thanks in advance, AB

128x128arizonabob
arizonabob's avatar
arizonabob OP
85 posts
 

Thanks for the response. I do think I have one of these as well as one that came with an old Pioneer turntable I once had. Appreciate your time.  AB

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cleeds
5,653 posts
 

arizonabob

... I do think I have one of these as well ...

I wouldn't be surprised! We oldtimers have all sorts of old audio accessories, cables, and tools stashed away "just in case" we might ever need them.

lewm
12,503 posts
 

It’s impossible to say much about differences between your two digital scales, except that the one with the range from 0.1 to 5.0 g is the one to use. For best accuracy, you want the VTF you seek (or any measurement of weight) to be within a narrow range afforded by the gauge. A gauge that reads up to 350g (!) is unlikely to be so accurate in the range where you typically would measure VTF for any phono cartridge. The other issue is the position of the weigh pan (the area wherein you set down the cartridge in order to measure VTF). Make sure it is in the same plane or nearly in the same plane as that of the surface of a typical LP. If the two scales differ in that regard, use the one that places the stylus tip in the plane of a typical LP when measurements are made. This means, of course, that you want to set the scale down on the bare platter or platter mat, NOT on the surface of an LP which will inevitably raise the whole scale a bit too high.

arizonabob's avatar
arizonabob OP
85 posts
 

I totally agree with you. As stated earlier, in order to get the arm load meter to the proper weight, the counter balance had to be pushed back to the very back of the tone arm. When I attempted to operate the automatic play, the arm became unresponsive. The (33.3)  speed light came on but the platter would not rotate nor would the arm come off the rest. I'm still looking for the teeter-totter type balance as suggested by 'cleeds'. By the way, the arm loader is closest to the horizontal plain of an LP. It will be interesting to see what a manual scale will register (if I'm successful in finding one!). Thank you for your response.   

arizonabob's avatar
arizonabob OP
85 posts
 

Follow up on my "weighty conundrum". I found both my Ortofon scales and I'm sorry to report that I am unable to get a repetitive reading on any of them. The VTF changes on each measurement even at 15 second intervals...So it's off to see my repair facility in hopes of getting some type of explanation as well as a solution. Thanks again to those that responded, it much appreciated. AB  

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