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Stylus force gauge accuracy; digital vs. mechanical? (Shure or the like)

outlawmws

outlawmws

On the Run
I’m wondering about how accurate these measurements really are in reference to the actual application. I don’t doubt the accuracy (within the limits of the device itself) of either breed of scale.

But the weight is measured with the stylus tip sitting .150, or more than 1/8” above the surface (As measured on my Shure, with the scale “centered”) of the record. (Assuming you are using a record to provide a flat surface for the scale, even without a record, it still sits 2X higher than a record surface)

The same would apply to a Digital scale. Depending on which pocket digital scale you had, the stylus tip would still be high compared to actual record force.

I bring this up because I don’t know how high the scale platform is for the digitals; are they higher than a Shure?

I’m certain that whatever the actual on the record force is, it is slightly higher than the scale is measuring as the arm is over center from level ,and the more it drops the more weight is applied. This difference works with the way we play the records so with a Shure, and it’s a known but relatively “Standard height” even if it is a bit more actual force on the record as played.

But if the digital is higher, it will measure a lower force than in the as played position.

I know this is more than theory, as I just set my stylus force without even a mat in place, (on the bare aluminum) with the mat, and mat + a record; and the shure showed lighter at each step higher. (I did not try to “Measure” the difference, the Shure is made to confirm a set weight, not measure different weights without a lot of fussy back and forth to reset the slider.

So: the question is, just how high is the scale platform on the various digitals, and what exactly is the change to actual stylus tip weight on the record surface. (Note that this will change with different mass arms and different arm “drops” from level)



EDIT: Please, let’s not get this into a session of "Its simple; do it my way" types of responses. Referencing what you use is fine, but please make it in reference to the discussion; how is accuracy affected by the height of the scale platform. :thmbsp:
 
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forget the digital junk with batteries and get the shure. accurate, reliable over time and easy to use.
you can put it on the bare platter and eliminate the recodr thickness. jeez this stuff isn't rocket science.
 
I've been using my $10 Shure gauge for about 25 years now.
It's damm near idiot proof.....so it works well for me!

Steve
 
I would disagree about digital scales being junk. If anything I have found the Shures to be on the unreliable side. Had 4 or 5 of them and all would read differently.

My Digital scale has been reliable and very accurate for some time now. Its about the thickness of an LP so no guessing in that department.

Don't get me wrong. The Shure is decent and you more then get what you pay for but when your stylus needs to be accurate the mechanical scales were not for me.
 
I would be very surprised if the Shure scale was any more accurate than a good digital scale, not saying it's better or worse, just that there seem to be some criteria beyond accuracy that sways people that really isn't readily quantified.
 
Is there really a difference in the quarter gram of tracking force a really lousy mechanical scale might have? If the tracking force is set to a reasonable level, somewhere toward the top of the tracking force range of the cartridge, ±.15 gram won't hurt anything and should be fine. I doubt that there is a quarter gram error in the SFG-2. Maybe some of the super cartridges will be more particular but the cartridges we talk about most of the time shouldn't exhibit much difference going from 1.5±.15 grams.

Since I frequently use test records to set up cartridges, using the SFG-2 is good enough for me and my budget at this time. I understand the increased accuracy of the digital scales but as stated this is not rocket science.
 
Never had a problem with my Shure. I've been setting up carts with it for about 15 years, always come out great. Yeah, the digitals might be a little more accurate, but
I just can't see it justifying the extra expense.

Dave
 
OldHifiguy: While I respect your sentiments, I wasn't asking for advice on which way to go. (I already own a Shure, whether I decide to try digital will depend on what I learn here.) I was asking about the accuracy as used, and that is a valid discussion.

Gear hound: Same message, I’d like to see this stay on topic, and not about specifically about preferences, or how long one has owned a type of scale

That said, I already classed the Shure as “the standard”, to repeat, I’m interested in the use of the different scales, and if the expected results are actually applicable to the record.

Grumpy: thanks for the info on the digital scale height you use. Can you tell us which one it is (Make/model), and if it is still available? From where? The ones I saw on Eprey seemed a lot thicker than a record, or even a Shure.

EDIT: similar message to the posters that posted while I was responding :D
 
Now that we're back on topic...... What I do is use some 2"X3" Post-It pads that fit between the platter and armrest to rest my digital scale on. You can add or remove sheets to make the top of the scale even with the record surface. Frankly, I haven't noticed more than .1g difference between setting the scale on the platter or on the plinth.
 
Got mine a couple of years ago for around 60 bucks if i recall. Not exactly mega bucks as some here seem to think.

This is a pic of the exact scale but its now being sold under many different names brands and mark ups.
 

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Hello Outlaw,
Many of "these" boutique digital scales are in many cases rebranded scales from China, and in this instance, one pays through the nose, for what may be in truth a $20-$50 scale at most.

Very high accuracy, and very good repeatability is good, if you swap cartridges on a regular basis, and wish to get back quickly to a previous optimum setting with a known Cartridge.

Other than that, the very best way to fine adjust VTF is by ear, not what a scale says.

What some do with some of these run of the mill digital scales, is make a platform from some type of non-magnetic material, say a thin strip of Brass, or Aluminum from a Hobby Shop, and make a ledge that the Stylus will rest upon, which can be formed-bent to be at the exact LP height. Most of these digitals have a Tare feature, meaning that whatever weight is already on the scale before you turn the scale on will not register, and upon fire-up, the scale will read 0.0g, or 0.00g, even with this added weight.

This "ledge" can then be secured to the weighing platform with a drop of glue.

Otherwsise, the other way, which can be more difficult each time using a digital scale with a fairly thick weighting platform, is to built-construct a pedestal that the scale will sit upon. Hope this helps, Mark
 
dread31 said:
Never had a problem with my Shure. I've been setting up carts with it for about 15 years, always come out great. Yeah, the digitals might be a little more accurate, but
I just can't see it justifying the extra expense.

Dave
Click to expand...

My digi-scale was all of 6 bucks plus I got a free upgrade because the seller was out of stock once the word got out about those scales around here.
I say to each his own when it comes to tonearm setup. If you like what you're using, then you're probably good to go.
 
The measurement pad of the digital scale I use (same as Grump’s by the look of it) is about 0.22” thick and if you are real concerned about dead accurate absolute measurement where the stylus tip hits the lp you would have to build a platform for it to get the height right – the measurement would change a very small amount over this distance with height on a pivoted arm. There is also the issue of LP thickness so I suppose you’d have to pick a reference (180g?) and measure the net height but this level of anal-ysis seems overboard to me.

I don’t worry so much about absolute accuracy as I like to get close to a recommended force and then work around it to fine-tune by ear. I have a cartridge that seems pretty touchy about VTF and an arm that is pretty cumbersome to adjust VTF on where the counter-weight must be slid along the arm after loosening a set-screw. This is why I love the digital scale; I can easily adjust around a reference in .1 or even .01 gram increments by simply reading the display, sliding the weight and measuring again after locking it.

Absolute weight is not so important in this mode – repeatability and fine adjustment is - so the miniscule inaccuracy the 0.22” thickness adds doesn’t matter so much. I just plop the scale down on the bare platter, measure my reference and accurately adjust around it.

I’ve come to love an accurate, easy to use digital scale for this reason and find it an essential turntable tuning tool.
 
KlipschFan61 said:
If you like what you're using, then you're probably good to go.
Click to expand...

Yep, old school here. I've thought about trying the Shure or a digital, but I'm not convinced it's worth the dollars with my cheaper setup. Good thread.

arg.jpg
 
well there are some folks that are quite as hoyty toyty as others on this forum so I'll bow out of the discussion.
 
outlawmws,

Great question, I have been wondering how height affects the accuracy of the scale. I don't have a shure or a digital scale, what I have been using is an RCBS 10-10 reloading scale because I had one. It is a balance type scale accurate to .1 of a GRAIN. Remember the conversion is 1 GRAM = 15.43 GRAINS. I did a little experiment in that I checked VTF at a height approximately the same as the record height. I then raised the scale using 1/8 in plywood and re-zeroed and re-weighed. The two values were 24.6 grains and 24.9 grains. I checked several times and the results were consistent.

level - 24.6 grains or 1.59 grams
1/8 in - 24.9 grains or 1.61 grams
5/8 in - 26.4 grains or 1.71 grams
7/8 in - 27.2 grains or 1.76 grams

Graphed these values are fairly linear and I would suspect that lowering the scale would produce similar results, though that is not very common considering the scale would have to be below table.

I used my sme 3009 with VTF set to maximum and stylus removed from cartridge.
 
Billfort said:
The measurement pad of the digital scale I use (same as Grump’s by the look of it) is about 0.22” thick and if you are real concerned about dead accurate absolute measurement where the stylus tip hits the lp you would have to build a platform for it to get the height right – the measurement would change a very small amount over this distance with height on a pivoted arm. There is also the issue of LP thickness so I suppose you’d have to pick a reference (180g?) and measure the net height but this level of anal-ysis seems overboard to me.

I don’t worry so much about absolute accuracy
SNIP
Click to expand...

This was the whole thrust of my question, and I'm not that concerned with the absolute accuracy either, just what effect changing the height has on the numbers. Your platform is about 50% higher than the Shure. Some platforms might be higher (Most Pics I saw of D scales look a lot higher) and if so, it is measuring light, and how light? (Again this will change with different mass arms and different arm “drops” from level)

So, can I ask for some of you D scale owners to try it, without changing any arm settings, at different heights, and report? If it is as Bill suggests, insignificant, great. If it starts being a significant %, then not so great.

I already KNOW it changes, just not how much!

Also if you could say what table arm you tested it on, as I strongly suspect it is higher on say the Dual 1019 -1229 series arms, and sat an ultra light arm on a custom table.

Thanks in advance! :thmbsp:
 
bsujeep said:
outlawmws,

Great question, I have been wondering how height affects the accuracy of the scale. I don't have a shure or a digital scale, what I have been using is an RCBS 10-10 reloading scale because I had one. It is a balance type scale accurate to .1 of a GRAIN. SNIP
Click to expand...

Hahaha, Wow! I know EXACTLY what scale you are talking about (Yes I'm a reloader) I have my dad's old Redding scale, still use it for reloading, and we have verified its accuracy against known weight so I know it’s good. I just would have never tried to use it for a force gauge! THATS thinking out of the box! :thmbsp:

I'd love to see pics of this being done!

And thanks for the test info! Looks like with your setup the differnce is pretty small.
 
Picture you want, picture you get. I did this on the floor so that I could have room to play. Someone may notice that it is not exactly as the numbers I have in the earlier post, that is because I had to stage this back up for the pix.

I have used check weights to verify this one also, you have to be a little careful as it is a bit cantankerous. I was fairly pleased with the linearity of the data however, even though the sample size is useless ( I know!!)

300 win mag. Why you ask, because I NEVER wonder if I hit something!!
 

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oldhifiguy said:
well there are some folks that are quite as hoyty toyty as others on this forum so I'll bow out of the discussion.
Click to expand...

But there's people here like me sir who "don't" want you to "bow out" of the discussion. Just because your view may slightly differ than mine, or other's here, doesn't mean your views are invalid, or not wanted-needed. Stick with us here in the group, and please don't be discouraged your common sense approach is a good one.

I do agree about "digital junk", in which the unknowing might shell out $250 for a chinese digital scale, which is just a re-branded $29 Scale from somebody like Old Will Knot Scales. Take the Clearaudio Weight Watcher Scale for instance.

Do a search on this Clearaudio Scale, note its price at the big audio stores, then go over to Old Will Knot, look up the Proscale LC-50 at $29, and try telling me this isn't the exact same Scale?

Clearaudio markets-makes some nice stuff, but on the other hand, I've come to believe thier philosophy is "There's a sucker born every minute, and we have just what you need"! ;-)

I took this el cheapo Proscale 50 Scale over by my machinist buddy a few weeks ago. He threw every lab calibration weight he had at this scale, and was amazed at it's dead on accuracy. Flip it over, what does it say in fine print....."Made in China". The same Scale Clearaudio has the gall to sell for $225-$250. Check it out! Mark
 
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