Experience With Linear Tracking Turntables

@billstevenson 

Maybe that is why I do not understand why you do not understand why there is no such thing as perfection with linear tracking tonearms. 

I never said that linear arms were perfect. But I have a load of arms both linear and pivoted, including gimble, unipivots, 4points etc - most of which are highly regarded - and none are perfect - it doesn’t exist.

But one thing I am clear about is that a significant advantage of the Eminent Technology ET2 and 2.5 which are my preferred linear tracker by some margin - no  mechanical intervention, captured air bearing amongst other attributes - is that with an air bearing linear tracker there is no anti skate required. Having been in audio for 30+ years, including distribution of high end back in the analogue heydays, the damage done to cartridges from incorrect anti skate is massive - I reckon 80% plus of cartridges on pivoted arms end up with skewed cantilevers within a year or 2.

And then of course is the tracking error with pivoted arms.

But I would agree with you in so much as there are plenty of linear trackers that are absolute duds - some much vaunted.

And I’m still very happy with the pivoted, straight, underhung Viv Float.

Well I must say that I have set up literally hundreds of turntables over the decades starting in the early 1970s while working at a high end hifi retail shop in the Seattle area.  All manner of arms.  A properly set up pivoted arm will not skewer the cantilever, not for the life of the cartridge.  I have to say that good arms do not have to cost a king's ransom.  Perfectly acceptable results are obtainable from, for example, Dual turntables, in terms of cartridge tracking and performance.  It is true that improper antiskating application can cause damage.  In my opinion, antiskating is probably not necessary for cartridges that require VTF of greater than 2 grams and certainly is not necessary for arms 12" long, and it is situational for arms at 10" or so.  This can be measured and determined best during set up by a competent set up technician, one who is using test records and appropriate software.  The issue of tracking error is generally over emphasized.  In most cases, for most musical material, it is imperceptible except for extremely modulated peaks, usually found at the very end of classical pieces (for examples, the 1812 Overture finale or the 3rd Organ Symphony) which is why the Stevenson alignment was devised and is in common use for those who worry about such trivia.  There are good and bad examples of both pivoted and linear tracking arms.  As an engineer, I include those that are over engineered to the point of absurdity in the category of bad designs.  Rule of thumb, any arm that costs five figures is over designed and those that drink their Koolaid from that punch bowl are getting hosed.  Big time.  

Bill, the skating force generated by any pivoted tonearm is directly proportional to VTF. (The equation for the friction force.) So the higher the VTF, the greater the skating force, requiring more not less AS to compensate.

Hi lewm.  Yes you are right and the generally accepted value is AS = ~ 0.1 (VTF).  It should be understood that there is variation in the amount of AS needed as the arm moves across the record. Also a record that is not perfectly flat will affect AS as well as VTF as the arm and cartridge travel across the record.  AS is always an approximation as you know.  Usually when too much force is applied it causes cantilever skew and resulting damage that Dover mentioned.  By contrast, I have never seen damage to a cantilever when no AS was applied.  This was true even with the very bad arm with high friction on the old AR turntable.  Another valuable lesson I have learned recently while setting up turntables with AnalogMagik is that AS can be adjusted over a fairly wide range without causing significant changes in distortion.  In other words, a little bit is enough.  There is no benefit to applying higher than a minimal amount of AS or even none at all.  To put what I mean into context, on my Technics SL1200 GAE setting up an Ortofon 2M Black LVB, VTF = 1.5 gm, set AS using the Technics scale = 1.5, I got a value for distortion of X (I am in NH, notes are in FL).  Then I set AS on Technics scale at values ranging from 0 to 2.5.  Distortion never varied by greater than 0.2% and usually much less.  I found the difference on my HW-40 (arm 10.5") to be essentially immeasurable when no AS was applied at all with a SoundSmith Hyperion, VTF = 2.0 gm.