Discuss The Viv Lab Rigid Arm

I think the slop problem arises because the liquid pivot allows too much movement.  Just a few microns will allow the stylus to change location relative to the platter and read signals that are not imparted by the groove.  I sometimes wonder whether conventional gimbal bearings are really good enough to give zero slop.

@clearthinker I was thinking the same thing. FWIW Triplanar uses the hardest metal bearings made worldwide to achieve 'zero slop'. To that end to my understanding they have a security clearance to obtain the bearings. 

@atmasphere    The hardness of the metal in the bearing is not the only issue.  The fineness of the machining is fundamental.

Another one I have thought about is my Simon Yorke Aeroarm.  This is a parallel tracking design, very lightweight with a distance from pivot centre to stylus of about 3 inches.  The arm has a round aperture sliding along a steel bar separated by an air bearing.  The clearance of the air bearing is 5mu centimetres.  The air pressure is 1.4 bar, held steady by a hospital grade compressor and control valving.  I have wondered what movement this might allow (if any) and noted such is likely to be in line with the arm and therefore the groove so not affecting azimuth.  I have never heard distortion of any kind on this rig which is my forever player and sounds simply wonderful with low-mass cartridges.

The hardness of the metal in the bearing is not the only issue. The fineness of the machining is fundamental.

@clearthinker 

Yes. The bearings in the Triplanar are tiny.

The problem you have with any arm with a short arm section is any record warp will be audible as a speed variation and will affect the bass impact since the tracking force changes with warp and bass modulation. To get around that the bearing must be in the plane of the LP. Think about two people carrying a couch upstairs. Who is carrying the most weight?

@mijostyn   The tracking error of the Viv varies as the effective length chosen. I f I wanted the Viv I would instinctively go for the 9 inch version, although quite a number of commentators have said they prefer the 7 inch (6 inch anyone?).  But whichever you choose I rather doubt the tracking error would be as gross as the 5 degrees you postulate.  Nevertheless I am curious that a quite a number of listeners say they cannot hear the resultant distortion on the 7 inch Viv.  I think it would be interesting to play sine waves on that and a conventional 9 inch arm using a line contact or similarly radical stylus and see if there is audible distortion.  It may be easier to perceive it on a steady state signal than with music.

To more realistically mimic the tracking geometry of the Viv, you would also have set your cartridge to the correct underhang.  Might actually be a fun experiment...