Tonearm adjustments on the fly

OP's question about what do other tonearms do?

MOST VPI unipivot arms (NOT the stock Classic 1 arm) lift the entire base on which the pivot is located.  The mechanism uses a fine-pitch screw to accessible on the arm base to make the adjustment.  Allos good on-the-fly adjustment.  

For a lot of tonearms with a "standard size" arm pillar, there is the Easy VTA base.  It replaces the original tonearm base with a hole and set screw for the arm pillar.  A fine pitch screw system using parts from a micrometer is used to gently raise or lower the arm at the arm at the pillar while the record is playing.  Once the correct VTA / SRA is attained, a set screw can be used to lock the mechanism in place.  Works GREAT on FR, Grace, Jelco and (IIRC) Linn arms.  I'm using it with a Jelco TK-850L.  Best combination I've heard.  

TransFi Terminator is a possibility. It’s a linear tracking hybrid: air bearing for horizontal, pivot for vertical.

VTA is easily adjusted on the fly. Beam horizontality is easily adjusted on the fly - and this is also a small azimuth adjustment. Large azimuth adjustments are a pain, but intuitive; ditto tangentiality, ditto VTF. All adjustments are reasonably stable and repeatable.

Low pressure air means no messy air supply maintenance.

So for a little pain and $1k you can have an instrument which competes with anything that costs less than a new car. IMO. I have two in an ESL based system, running a Koetsu and a Miyajima.

My VPI Classic 2 has that feature.

Mike

Pete Riggle make an adaptator for your own arm. The VTAF. I use it with my origin live conqueror mk II and am very pleased. Following a report from 10 audio Jerry Siegel found that this arm sound better with the VTAF.

We need to understand that accurate reproduction of wiggles in a microscopic groove can only be achieved if there is a fixed spatial relationship between the TT main bearing and the stylus tip. Otherwise the stylus transmits movement that is not driven by the passing modulated groove.

This fixed relationship must be obtained whilst allowing the arm to move in two planes, so the bearings that do that must have no movement other than those, i.e. no chatter.

This is difficult enough to achieve without building into the spatial relationship three or four more adjustments on the fly.  These will necessarily allow unwanted movement that will break the fixed relationship between stylus tip and main bearing.  Remember we are talking about movements of less than 1000th of 1mm.

In any case it is not necessary to adjust azimuth once it is correctly set.  However thick, all LPs are flat (unless they are warped - and should be discarded).

Accepted VTA on the fly is useful to correct the small differences in thickness between discs, but this is the easiest geometry adjustment to achieve without unwanted movement, by raising the arm pillar using a rack and pinion with low geared adjustment via a wheel control that can be calibrated to achieve total accuracy for a record of known thickness when correctly set up at a base value.

Leave the rest well alone.