@atmasphere cc @frogman
I left the ET2 out on several counts. The first being that the lateral tracking mass is a multiple of its vertical tracking mass. This makes selecting a cartridge rather difficult-
Actually you are looking at this the wrong way round. The horizontal effective mass as adjustable and the decoupling of the counterweight in the horizontal plain means that you can tune the arm to the cartridge.
Secondly, if you go to Bruces website and look at his testing results, the split effective mass in the 2 planes reduces the peak of the fundamental resonance significantly, resulting in more accurate bass and better tracking.
As an example I ran a high compliance Shure V15vxmr in the ET2 when I had a hiatus from audio for 10 years. After that time ( still with the original stylus in place and stabiliser brush removed ) the cantilever was dead straight and negligible stylus wear - so much so that someone bought the 10 year old cartridge for what I paid 10 years earlier after much examination with Lupe and micro scope.
it uses an air bearing. If you want the cartridge to play without coloration, there can be no play between the surface of the platter and the mount of the cartridge. We know that bearing play makes a difference since you can use higher pressure pumps and hear a difference.
Yes I agree, but the upside is the removal of tracking angle distortion - removing phase and time error caused by tracking angle distortion - and unparalleled reproduction of the soundstage. The removal of phase distortions inherent in pivoted arms also improves timing and coherency. If you bought an ET2.5 and listened to your own records that you cut with the ET2.5 properly set up you would be shocked - particularly in terms of soundstage reproduction and preservation of phase.
Finally the arm mass is high enough that a decision was made to run only 4 wires rather than the traditional 5. Cartridges are balanced sources and they don’t make a lot of voltage. When the arm ground is integrated into the left channel signal, it can be noisier.
Most ET owners rewire their arms, with no ground. Never had a noise problem, and balanced configuration is easily attainable. With current wires from Audionote & Kondo you could run 5 wires with less resistance than the original wiring if you need to.