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In Reply to: RE: Getting accurate stylus force gauge readings posted by Peter C on March 15, 2017 at 05:23:06
The Acoustech gauge is the Camrong one from China as sold by and branded by many companies. I have been using one for years and have never experienced any difficulties with magnetic fields . What is unique about the Benz cartridge that makes its magnetic field different to that of other expensive MCs using rare earth magnets?
Anyway I am not sure that I understand what you are doing. You say that you take the gauge and you tare it. OK so you should have no load on the gauge. Then you press the Tare button. You wait until the display shows CAL then when it flashes you place the supplied 5g weight on the load pad and wait for the display to settle. Eventually it shows 00.00. Remove the weight then put it back so that the gauge is now reading the weight again. Instead of 5.000 it will probably show, say, 5.004 as that is the limit of its accuracy (NB: more than required for setting VTF). Is this what is happening away from the cartridge?
OK, assuming that all is OK so far, how do you then know that when you set the cartridge down on the load pad the reading is too high by 0.6g (rather a lot). How are you measuring this? Are you checking it against another gauge? How do you know which is accurate?
We know in my example above that the gauge over reads by,say, 0.004g. However in accuracy terms that final decimal point is unreliable and should be ignored anyway. BTW the supplied 5g weight is not accurate to that level and laboratory weights that are would cost more than the gauge (at least for the average price of this gauge which varies from one brand to another). Note that the repeatable over reading in my example is a tiny amount yet you are saying that even away from the cartridge when calibrating it the reading varies by ± 0.2g which for this or any gauge is high.
Please also note that the reading will vary if the gauge isn't on a perfectly level surface or if the load is placed other than exactly on/within the black dot target. Also when using it needs time to settle.
Given the levels of misreading that you quote I am not rejecting the possibility that the sample of gauge that you have is faulty ( if you are using it correctly).
As for magnetic attraction the gauge is made of plastic and the only metal surface is the brushed aluminium (non-magnetic)surround to the load pad. So I do not understand how the Benz is attracted to it. I just checked mine against a magnet and there is no attraction at all.
How does the gauge struggle to zero out when you tare it " due to the overwhelming magnetic field " when the process of calibration does not involve the cartridge at all?
Edits: 03/15/17Follow Ups:
I'm not calibrating the gauge, just taring it to zero it out. I'm coming up with .6gm figure because if I just take the VTF reading, I get about 2 gm. If I try to tare it to zero first when the cartridge is hovering above, noting that the gauge fluctuates ever more wildly as the cartridge is brought closer and closer until it's just above the weighing platform, not only are my efforts to zero the gauge unsuccessful, but the reading with cartridge on the platform is about 2.6 gm. The Shure gauge confirms that's not correct. Even with it's inaccuracy, it shows roughly 2gm, although it may say 1.8 or 2.1 or something like that - not precise as we know about the Shure gauge.
Apparently the Benz Ruby 3 has a high magnetic field. I also can't use the VPI platter ring because of its ferrous content, which forcibly draws my cartridge to it - it almost bent the stylus.
Also, I think people are getting confused about the materials used in the digital gauge. It doesn't matter that the gauge platform is plastic and aluminum. I'm contending that the strong magnetic pull is interfering with the electronics within the gauge.
I am suspecting that you either haven't got or haven't read the instructions.
You cannot "zero" the gauge by pressing the TARE button. The TARE button opens the calibration program which is its sole function ( display shows CAL when you press the TARE button for a few seconds) for which a 5g weight is necessary. When the gauge establishes the 5g load it then resets its zero calibration. If you haven't used the weight then this is why your attempts have been unsuccesful . If you click the link you will see your gauge and you will see that the weight needed to set zero (calibrate) is clearly shown. Do you have this? If not or you don't use it then you have never set the zero calibration and this is why the readings you have are odd.
Do you have a suspended turntable? If so I would point out that any cartridge will make the gauge change figures as you move the arm towards it as you are also moving/shaking the whole turntable by a tiny amount which the gauge is sensitive enough to register. Nothing to do with magnetism. My one behaves exactly like this. You need to move the cartridge to its correct place above the load pad and then leave it in raised position until the gauge returns to zero. Only then lower the cartridge and take the reading once the gauge settles again ( you can tell when it has as a small circle appears in the top left of the display). It is not an instant process.
BTW, The company that makes these gauges makes at least three variants. One displays to two decimal places, one to three and there is also a "giant" sized version that also displays to three places. The two place gauge is cheaper than the three place one and many people complaining about the price variations ( although they exist) do not appear to know about these variants and seem to assume that they are all the same.
I have never seen one made from metal as one poster suggests although some of them, like my one, use a plastic and finish that looks very much like metal.
They are surprisingly accurate when used correctly. I have several laboratory weights accurate to two decimal places: 5, 2 and 1 gram. Not only is the gauge accurate (I have a three place one) to two decimal places, it is also linear i.e. equally accurate at other loads not just the calibration one. I assume that the two place type is accurate to one decimal place.
Correction: I have been playing around with mine and found that the TARE button will set a zero figure ( not shown in my instructions). As will just leaving the gauge without any load. However that zero is not in relation to anything without the weight having set the calibration in the first place. My experiment showed that even breathing lightly on the gauge canged the weight displayed, including zero. That's how sensitive it is.
I gather the basis for your idea is that the gauge readout goes unstable when the cartridge even approaches the weigh pan, without even touching it. Is that so? That's interesting. I will have to check it out with mine. I've owned mine for several years now. Since I have all too many cartridges and turntables, I use it quite a bit. It's always rock steady in read-out and never reads anything but zero when tared with no weight on the pan. My scale is identical to the one shown by Fremer in the URL I posted above (but I did not pay $80 for it).
If your weigh pan is magnetic or if something under the weigh pan is magnetic, I could imagine that the readout would go unstable even with the cartridge hovering over it but not touching it, because in that case the magnetic attraction would be pulling upward on the weigh pan, which would no doubt perturb the readout.
I have the same metal bodied (I assume it is metal) as you do and have the same issue with my Ortofon Jubilee. The weight goes nuts while lowering the cart down to the measurement point. I constructed a similar gizmo as JE and the 5 gm weight reads the same whether on the platform or cantilevered off on the gizmo. Interestingly, once the cartridge is on the platform or the gizmo, the final weight is close to the same. I just do both measurements and compare. Then I don't worry much because they are very close and I have bigger things to worry about these days.
I have an Ortofon MC2000, the vintage MC with vanishingly low output. I was lowering it down on the platter of one of my DD turntables when it suddenly got sucked down flat onto the platter mat. Fortunately, the suspension took the hit and seems to be OK. I was using an LP-sized piece of TI Shield under the platter mat, to block EMI from the motor from causing issues with induced noise. Turns out TI Shield is partly ferrous and its ferrous layer was being magnetized by the underlying rotor of the DD motor. That was too close to the magnets of the Ortofon, and the two tried to kiss each other. This had never happened before with any other (non-Ortofon) cartridge. Later on, an Ortofon guru told me that they tend to place the magnet near the bottom of the cartridge body which makes it susceptible to this sort of accident. Maybe your problem with your Orto is of a similar nature. When I removed the TI Shield, the problem went away entirely.
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