Unipivot tone arms

Some unipivot tonearms (VPI for example) are poorly designed because they are inherently unstable, thus the tracking force is in a constant state of fluctuation as the tonearm traverses the record. I suspect this is why VPI has been moving toward gimbal bearing arms in recent years.

Graham Engineering knows how to make a proper unipivot.

I have a VPI unipivot arm and it tracks beautifully with my Soundsmith cartridge. I have tracking force adjustment and alignment as well. 

I’ve had a Moerch UP-4 on my Scheu Premiere MKII for 20+ yrs.

Used with a couple Ortofons and Lyras…setup is currently in my A/V system (not main) but works and sounds great.

Have also heard and operated (not my own) VPI unis with ZYX and Lyras.  Work and sound just fine.

Most modern (meaning brought to market within the last 10-20 years) unipivots are not really unipivots in the original sense of the term, because most manufacturers have modified their unipivot designs to reduce or eliminate their capacity to rotate in the plane of the pivot, which makes the azimuth unstable. These modified Unipivots are also made less prone to "chatter" at the bearing point, by use of magnets, etc. As a result, the better modern unipivot tonearms, like the Kuzma 4-point or the Graham or a VPI with their add-on modification, are really excellent tonearms, but expensive.

One of my favorite turntables was an LP-12 I got used in 1975.  This was before they added electronics to it…just a Scottish AR or TD150.  My roommate was in the UK on a fellowship so I asked him to bring me a Keith Monks arm for it.  I mounted it with a Sonus Blue Label I selected from our store inventory as having the straightest cantilever, and used it with an ARC SP-3a, a Dyna PAT-5 and a DB Systems 1A until our home was burglarized. All that remained of it were the little dusty blobs of liquid Hg on the floor!

The KMAL unipivot was silicone damped, so its rocking motion was not readily apparent. The arm wiring ran through 4 baths of liquid mercury in lieu of copper wire to eliminate, not merely reduce, any torque effects on the stylus.