The late Brooks Berdan---well known in the hi-fi business, and referred to as Mr. Analog---probably mounted and set up more arms & tables than anyone else in history. He was one of Bruce Thigpen’s first dealers, and mounted a LOT of the original ET arm on his then (1980’s) favorite table---the Oracle Delphi.
Brooks---having worked in the race car field before entering the hi-fi business---recognized the Oracle had a non-optimum mass distribution in it’s floating subchassis, and came up with a mod to eliminate that fault (Oracle eventually incorporated Brooks’ idea into the Delphi). He may have noticed the Oracle’s mass distribution problem because of the way the moving mass of the ET arm affected the subchassis suspension of the table; It was inherently unstable if left stock.
When the TNT was introduced by VPI, Brooks favoured it for use with the ET arm, as the TNT provided a much more stable platform for the ET---higher in mass and having a stiffer spring suspension. Brooks sold that ET/TNT combo for years, installing one in the system Bill Johnson had in his winter home in Palm Desert, about an hour-and-a-half hour drive east of Brooks’ shop in Monrovia.
Both Bill and Brooks are gone, and the TNT is history, but the Eminent Technology arm lives on!