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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
 

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  

arizonabob's avatar
arizonabob OP
85 posts
 

To the good people that responded to this and to any of you that find this, I got an answer. My repair technician explained to me that the inner bearings for the arm have defaulted. This turntable has been such a great one (for me) for the last 23 years. The play options were the best, especially the 'locate' option which allowed me to move the arm across the record without having to physically touch it. My steadiness isn't what it used to be and saved more than one LP from drops or scratches. You audiophiles can say what you like about full automatic direct drive turntables (it was a Denon DP 47F), but for me I only wish I could find another new one. I'd buy it in a heartbeat. Now, even in my state of grieving, I'll need to find a replacement...a sad day. 

lewm
12,506 posts
 

One other important issue with your two scales: be sure their weigh pans (the platform whereon you place the stylus tip) is totally nonmagnetic. Most steel has at least some iron in it, and that can really screw up measurement of VTF, because the cartridge contains powerful magnets as you know I’m sure. One sign of this problem is the scale indicates negative weights when the cartridge is hovering over but not touching the weigh pan. Because the magnets in the cartridge are pulling the weigh pan upward. I bet your 350g scale has a ferrous weigh pan.

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