Linear tracking arms

Leep...Yes, the arm is part of the Sony PS X800 turntable system. It does not surprise me that some other linear tracking arm is mechanized in this way because it makes a lot more sense than trying to create a frictionless air bearing.

My Sony PS X800 turntable has a linear tracking arm, and I guess it works a bit different from ones described above.

The arm is pivoted (so there is no jaring sideforce when the arm lowers to the record, or at any other time) but the pivot point is moved as the record plays. Arm movement is biased to the speed needed for nominal groove spacing, and then adjusted up or down as necessary to follow variable groove spacing, according to the measured angle of the pivoting arm. The system suposedly regulates tracking angle within 0.05 degree (for the entire record).

Sorry about it being a Sony, but the damn thing works great.