Anti-skate and other hair-pulling endeavors

J!m

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#1
So, with the Kenwood table, I found it necessary to make a heavier weight for the anti-skate apparatus. I wasn't understanding WHY at first, but the fact that I'm running a microlinear stylus, v. a spherical one, makes perfect sense. The more contact area, the stronger the centripetal force. Duh.

But, I have a feeling now that the entire geometry of the mechanism was designed around a spherical stylus, and the simple addition of weight may not be totally effective (or the arm is full of compromises to meet a sales price point- probably that), but, it IS much better now.

I mentioned the parabolic curve of necessary anti-skate force on a record to offset the skating force: 100% at the center of the record, 110% at the outer grooves and 105% at the inner grooves. If the Kenwood thingie is providing a linear change, that could be why it's not working well. But, based on the way one arm slides on a second arm, as the yoke rotates, the length of the first arm effectively changes as it rotates (which changes the length of the "lever" acting on the supplied force). And, as the mass is raised from below the record surface, to be parallel with the record, and then above parallel, this also affects the actual force applied. It is actually quite complicated, and I don't have a measurement method to determine the two (or better, three) points of the travel here to plot something and make sense of it (and that math is well above my pay grade). So, the force applied for anti-skate IS changing throughout the record surface. I just have no way to know, other than testing with the test record, that it's right.

Recently I made a copy of Steven Stills 2 for @Bob Boyer and I was disappointed with the distortion of the horns on the last track. That's what got me digging into this deeper in the first place...

Anyway, I played it again last night, to see if my wonder weight eliminated this distortion. And, it did not. It is significantly reduced, and now audible on both channels about equally (so moving the weight won't do jack). It does just barely pass the HI Fi news test record test, so it's tracking well. So, I either have a bad pressing, or prior owner damage to these passages with a worn stylus and/or poorly set-up arm. The rest of the record sounds really clean and clear, so I don't think it's play wear as the primary culprit. I am very interested to do follow-up testing with the modified Rega as well as the Micro BL-91/ MA-505 arm combo.

Can the fancy set-ups do better? Is it worth all the effort to upgrade arms (and other isolations) to extract better, clearer sound? Well, I'm a gonna find out.

One possible hope, with this Kenwood table and cartridge combo, it to start playing around with the tracking force (and then resetting the anti-skate), to see if going to maximum tracking force will improve it. I am currently at the center of the suggested range, so I have a little room to play here (about 0.5 gram either way I believe).
 

Bob Boyer

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#3
Following your tests with keen interest, Jim. I've never understood the relationship between tracking force (weight) and anti-skate force other than to set the anti-skate dial at the same force as the tracking weight (force). I've always felt a bit silly using a high-dollar arm like the SME 309 without really knowing if there's more to be extracted from it with some careful calibration.

But it do look purty...
 

Vintage 700b

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#4
Getting everything set up correctly is just a matter of correct order of operations. I have a protocol when I set up my SME 3009 and you definitely will hear it when it is correct, as well as lowering the wear factor on your vinyl to close to zero. Making sure that the headshell is aligned on its "roll axis" allows everything else to be set. I use a template to achieve the correct geometry (swing) of the arm relative to the spindle centerline. The entire arm is moved back fore or aft on the fulcrum to achieve this, template makes it easy.
The tracking force adjusts the position in the groove up and down (after leveling the height of the arm, which is critical) by setting the "preload" so to speak using the manufacturers recommendation for the cartridge. I set this with a small scale mounted about 1/2 way along the "swing" that I mentioned before. The anti-skate adjusts the position side to side in the groove. When it is correct it tracks the left and right side of the groove equally. That is why the "swing" adjustment needs to be right on. If that is not correct, you will hear distortion in one or both channels, often at the end of the album, closer to the spindle.
I have found, at least with the SME 3009 and 3012's that these adjustments stay put. I have been running an SME for almost 50 years, and many of the albums I bought new back then, and played the heck out of, still sound amazingly good. I cringe buying used vintage albums, because they may be "shiny, glossy, and Near Mint looking....", (Visual Grading ????) but they were played with a finishing nail mounted on a 4-pound tonearm. Treat em' right and they will reward you.....and sound oh soooo good through a WOPL'd amplifier!
 

J!m

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Playing records is actually highly complex.

It would be slightly easier if the groove was a single tone at a fixed amplitude. But even so, you have constantly variable surface speed from beginning to end of the record.

So, surface speed change is linear, and radius change is linear, yet skating force in non-linear. Really fun stuff.

And Bob, the relationship between tracking force and anti-skate force is not that simple, because of the varying shapes of the stylus.

I think the Hi Fi news test record is the best way to set it. The distortion is clearly audible, as is the corrections via anti-skate adjustments. But, if you have a round stylus, you need less anti-skate than an elliptical. The increased surface area contact causes increased skating. So unless it’s conical, you will need more than the “rule of thumb” says. I needed a lot more. Like 300% more…

image.jpg
 

J!m

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#7
It’s worth the effort.

And on some records it won’t matter. But if the modulation is high, the distortion comes on strong. You can hear it pretty clearly in that CD of Steven Stills 2. Just cue up the last track and listen to the horns.

Even making the Kenwood as good as it can be, it’s still there now. Reduced from what is on that recording, but there nonetheless.

That record has become my unofficial distortion test. I’ll see how it does with my modded Rega and the BL-91 once they’re done. It could be a bad record for a million reasons but it plays very clean otherwise so I somewhat doubt it.
 

krellmk

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#8
Playing records is actually highly complex.

It would be slightly easier if the groove was a single tone at a fixed amplitude. But even so, you have constantly variable surface speed from beginning to end of the record.

So, surface speed change is linear, and radius change is linear, yet skating force in non-linear. Really fun stuff.

And Bob, the relationship between tracking force and anti-skate force is not that simple, because of the varying shapes of the stylus.

I think the Hi Fi news test record is the best way to set it. The distortion is clearly audible, as is the corrections via anti-skate adjustments. But, if you have a round stylus, you need less anti-skate than an elliptical. The increased surface area contact causes increased skating. So unless it’s conical, you will need more than the “rule of thumb” says. I needed a lot more. Like 300% more…

View attachment 63000
https://www.discogs.com/sell/release/3212139?ev=rb
 
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