Skating Issue with Linear Tracking Tonearm

[DanJP]

I am having an issue with one (but not all) of my cartridges skating outward with my linear tracking tonearm. This issue has me puzzled so I thought I would see if anyone here might have an idea on what might be the issue.

I have a heavily modified Maplenoll Ariadne turntable. I custom machined a goniometer stage and mounted the arm air bearing to it so I can change SRA on the fly without having to reset the cartridge overhang. I also machined a custom carbon fiber arm and custom fully adjustable headshell.
I have been using this table for a few years already and it has been working flawlessly.

What I have noticed recently quite by accident, is that when I use my Denon DL-S1 cartridge it will skate outward if placed on a blank disc. The issue is that this only occurs with this cartridge. I have a Audio-Technica AT-ART9XA with a Shibata stylus and it does not exhibit this issue meaning that it stays stationary as expected. I initially thought that I had set the overhang improperly, or perhaps the arm bearing got bumped out of alignment, or the table/arm was out of balance. So I checked all of these and everything is where it is supposed to be. The bearing is where I originally placed it, the table is level as is the arm as verified by floating the arm and ensuring that the arm is stationary. I verified that the stylus is exactly on the tangential line. I also verified that the cantilever azimuth is exactly perpendicular to the tangential line and that there is no zenith tilt. So the only difference is that the Denon DL-S1 has a "special elliptical" not sure exactly what that cut is and the VTF is 1.3gm, and the ART9XA has a Shibata and the VTF is 1.8gm. Other than that everything else alignment wise was the same. I also have an Orsonic SG-1 skating force meter that used to verify that the arm is level as a double check.

To try and figure out what is going on, I tried moving the cartridge forward/backward which should have changed the skating but it still skated outward. I also tried rotating the azimuth/zenith and that did not change anything either. So I am perplexed as to what is going on.

Any thoughts are welcome.

 

[sound hound]

Science demands replication. Essentially, you have a sample size of 1. I guess you could decrease the vtf of the AT cartridge to 1.3 or increase the vtf of the Denon to 1.8, to see if there is any change. (or try a third cartridge if you are not comfortable making either of these changes.)

 

[loudnoises]

Unless you hit the pivot distance of the record exactly, the stylus is seeing a lateral force of some measure. Could be a hair or two short and it would see a force sending it outward.

Or maybe the diamond is twisted a hair?

I might try slight cart adjustments to see if it affects the drifting. This feels like a very very precise setup you have there and I bet you're well within the tolerances most of us would accept happily.

 

[DanJP]

Science demands replication. Essentially, you have a sample size of 1. I guess you could decrease the vtf of the AT cartridge to 1.3 or increase the vtf of the Denon to 1.8, to see if there is any change. (or try a third cartridge if you are not comfortable making either of these changes.)

As stated in my previous post, I have varied the VTF for the denon and there was no change in behavior. I also changed the zenith and overhang and again no change. I do have another Denon DL-S1 that is older than the one I have been using and I put that on today and it also is doing the same thing. I also looked at the stylus under the microscope and that cartridge also has a slightly skewed stylus so I think that it just might be how they were manufactured. Both seem to be off by several degrees.

 

[DanJP]

Unless you hit the pivot distance of the record exactly, the stylus is seeing a lateral force of some measure. Could be a hair or two short and it would see a force sending it outward.

Or maybe the diamond is twisted a hair?

I might try slight cart adjustments to see if it affects the drifting. This feels like a very very precise setup you have there and I bet you're well within the tolerances most of us would accept happily.

Agree. As far as I can tell the diamond is off by several degrees so more than likely that is what is causing the issue. I did change the overhang, zenith, VTF, etc. and it would always drift outwards. It would just be nice to understand why this particular cartridge exhibits this behavior.

 

[loudnoises]

Agree. As far as I can tell the diamond is off by several degrees so more than likely that is what is causing the issue. I did change the overhang, zenith, VTF, etc. and it would always drift outwards. It would just be nice to understand why this particular cartridge exhibits this behavior.

Folks have had good luck with usb microscopes, but there are limitations. A retipper could give you an accurate assessment.

Maybe a fozgometer could provide some insight? I've always wanted one but can't justify the cost. There aren't many tools that can really tell you what's happening at that contact point. You've tripped my curiosity but I can't offer much beyond moral support for this problem.

 

[Nat]

This may be a miscommunication, but you refer to overhang, which is the distance beyond the center of the spindle at which the stylus needs to be positioned which combines with the offset angle to give low tracking error in a non linear arm. But linear arms must have no over (or under) hang if they are to be properly aligned, and they are aligned on a radius, not a tangent.
I may be reading more literally than you meant, but I believe underhang would give the result you describe. So it would be worth checking to see if the stylus is on a radius and parallel to the arm track.

 

[DanJP]

Folks have had good luck with usb microscopes, but there are limitations. A retipper could give you an accurate assessment.

Maybe a fozgometer could provide some insight? I've always wanted one but can't justify the cost. There aren't many tools that can really tell you what's happening at that contact point. You've tripped my curiosity but I can't offer much beyond moral support for this problem.

I really don't want to send this to a retipper. I had a denon DL-304 retipped by Soundsmith with their saphire/line contact stylus and that cartridge went from a very nicely refined sound to one that was harsh with an almost 10db rise by 20KHz making it almost unlistenable. So definitely don't want that with the DL-S1.

I had looked into the fozgometer but I have all the test equipment I need as I am a retired engineer so I can do everything that the fozgometer can do. I would like to just purchase their vinyl for the test signals but last I looked you can't just order the vinyl

 

[DanJP]

This may be a miscommunication, but you refer to overhang, which is the distance beyond the center of the spindle at which the stylus needs to be positioned which combines with the offset angle to give low tracking error in a non linear arm. But linear arms must have no over (or under) hang if they are to be properly aligned, and they are aligned on a radius, not a tangent.
I may be reading more literally than you meant, but I believe underhang would give the result you describe. So it would be worth checking to see if the stylus is on a radius and parallel to the arm track.

Absolutely agree. And I yes I thought that underhang would cause the issue so I purposely moved the cartridge to get some overhang assuming that would cause the cartridge to skate inwards instead of outwards but that did not happen. It still skated outward which is why I started this thread. Yes the stylus is exactly on the tangential line so not over/under hand at all. It seems not matter what I try (azimuth, VTF, etc.) nothing will cause it stop skating. I do need to try changing zenith to try and approximate the stylus skew and see if that is what is actually causing the issue.

I do know that this is not being caused by the turntable/arm because my AT-ART9XA stays stationary as does my Orsonic SG-1 skate force meter which has a
7x18 micron elliptical stylus and my Denon DL-304 that was retipped with a line contact. But both my DL-S1 cartridges exhibit the exact same issue being both skate outward. So right now this seems to be confined to just the DL-S1. So far the only thing I can see that is common between both DL-S1 carts is that the stylus is skewed by a few degrees.