Linear tracking turntables, whatever happened?

The best linear tracker tonearms use the same force for movement as a pivot arm - the groove.

This depends on what is meant by this statement.
A number of linear trackers employ an air bearing, and thus have lateral tracking mass that is several times that of the vertical tracking mass. Quite often with such arms the side to side forces on the cantilever become the tracking angle error! This can exceed a good radial tracking arm.


So I'm not sure that qualifies as 'The best'.


A servo to control the rear of the arm as the arm moves across the LP (such as the old Rabco SL8) is a better solution, although the Rabco itself had many other problems. But if a modern version of such an arm were built, it could easily solve most of the issues that were a plague to the Rabco.

ok - I will rephrase.
The best linear tracker tonearms use the same force for movement across the record as a pivot arm - the groove.

@ct0517
That suggests the possibility of an air bearing.


I don't have a business relationship with Triplanar, just for the record. I do own two of his arms.


I saw a linear tracker eventually fatigue a Sumiko Boron to the point that the cantilever just fell off the cartridge. No particularly bad-ass records used. Prior to that happening, you could see the cantilever move from left to right. Clearly too much compliance.


I owned a Rabco for many years. I built a servo for it so that would be reliable. The servo also took some time to spin the motor up or down; in this way it would establish a speed depending on the cut of the record and didn't make a lot of motor noise. I also replaced the arm 'wand' with a carbon fiber setup that was lower mass. But the track that the arm ran on was its downfall- the track had resonance issues and used poor bearings to support the arm.

When the air bearing arms came out I took a good look at them, as I spent a lot of time at our first dealership, who also carried the arm. It gained a reputation for eating cantilevers. Clearly whatever cartridge you are using is more durable- what are you using?

Understanding these design differences will go a long way towards setup of both tonearms. If anyone is toasting carts on an ET2 they have no idea how to set it up.

Sounds to me like your dealers were Personality Type B...8^0.

@ct0517
Looking back on it, I think you are right.