Agreed about the Trans-Fi. Not only is it a good air bearing design, so the lateral forces acting on the stylus are negligible (think about the mechanical advantage of a spiral a meter long, acting over the width of a groove - a distance measured in micrometers), but it’s adjustable. As adjustable as any arm made, and that alone makes it a contender.
Let’s talk about adjustability. Tangentiality - fiddly, but perfectible. An old record, a good micrometer, a bright light, and half an hour. Mass - just add brass weights to the conveniently space holes. Resonance - lay Moongel or Sorbothane on the flat surfaces, as much or as little as required - as required for your cartridge and your taste.
VTA adjustment on the fly - and so easy it’s trivial. VTF a bit crude and fiddly, not on the fly, but intuitively obvious. Azimuth is the toughie - fiddly, but intuitive and very stable. Thing is, you start where most others end - and you end with 1 or 2 minute of arc precision (with a mod - see below).
Forget about overhang and choose-your-poison protractors which pretty much get it right - for parts of the record. And forget about almost-right-I-hope anti-skating. Instead, rejoice in Vic’s measurement about forces acting on the stylus - tonearm wire dominates.
Add the clever engineering which makes use of standard parts instead of precision machining, and you have a low-cost ultra high end device.
Is it perfect? No. The beam is cantilevered out, and so it’s just as unstable as other air bearing arms (that is, not very, but a little). The beam should hold adjustment to a few minutes of arc for perfect horizontal orientation. It doesn’t - it’s only stable to about 10 minutes of arc, but on the other hand, it’s a predictable amount in a predictable direction. I’ve built a support for the other end of the cantilever, and it solves both issues.
The vertical pivot is higher than the stylus by a centimetre or more. That means slightly compromised performance for warped records. The wand is only 70mm long, which accentuates the problem. On the other hand, the wand is only 70mm long. So that’s a tradeoff. In practical terms, it affects about 3% of my records negatively and 97% positively.
Last, there is a very minor aberration in air pressure on the saddle, for a few seconds, three or four times per side. The only cure is going to be an amorphous carbon bearing - costly, clunky, high pressure, and probably custom. But if I do that, I suspect I’ll have the best, most versatile cost-no-object tonearm in the world.
Or, you could settle for $15,000 performance for $1,000.
System - DIY air bearing TT, Koetsu, DIY electronics, ESL’s.