I am the happy owner of the 7" Rigid Float CB (carbon fiber) arm. I met Akimoto-san in March near his home in Kamakura. He is a wonderful human being; communication worked well and he explained to me the important parts of his design, most importantly - as had already been pointed out earlier - the complete decoupling from vibrations by means of the floating suspension: the arm floats in a viscous oil and is kept in place by a strong internal magnet pulling it down towards the rigid/stationary part of the housing w/o touching it. Imagine a ball in a bowl floating on a film of liquid: gravity will always pull it towards the center; now replace gravity with magnetic attraction, and you get the gist of the mechanism. It's comparable to a uni-pivot arm without the mechanical drawbacks (I myself have used the Woody arm for a long time: I loved its vivid sound, but hated the hour-long set-up routine). The second, and in my opinion unique feature is the complete freedom of placement: the arm comes as a self-contained (and quite heavy) unit that can be placed at any point around the platter, even away from the plinth, as long as the stylus can be positioned into a tiny hole in the placement template (a thin rectangular piece of plastic foil) above the platter. The entire set up, including VTF after cartridge mounting on the supplied head shell, takes no longer than 10 to 15 minutes. Akimoto-san holds a degree of mechanical engineering from the University of Tokyo, Japan's top university, and he is also a passionate audiophile. Combine the two, and you get this iconoclastic masterpiece, which sounds like it wasn't there at all. Needless to say, I bought the arm while we were still enjoying sashimi at a tiny place near the railway station - and never looked back. It's a true game-changer!
Straight tonearms without offset angle
In the October issue of Stereiphile, there was an article on a tonearm that had no offset angle and therefore had no skating force. The disadvantage of this is at the beginning and end of the record, the tracking angle error was much greater than what you get with an offset angle. For conventional tonearms that have an offset, and require anti-skating, which can never be perfect, the typical tracking error has a supremum of about 2 degrees, and according to online Lofgren calculators, this imposes a second-order harmonic distortion less than 2%.
I have a single-ended triode amplifier consisting of vintage globe 45 triodes transformer coupled to 833A SETs which drives Magnepans. Such SETs typically have second-order harmonic distortion as high as 10% which does not hurt the sound. A straight tonearm without an offset would have a maximum, or supremum tracking error of just under 10 degrees. If this causes a second-order harmonic distortion of less than 10%, would not this be irrelevant in a SET system? Is there any way of calculating this, or has this ever been studied?