@chris
I think the reason for the ET2 spindle design was
a) it was quite brillant with any cartridge (and still is).
b) the ET2 spindle is ca. 23 g vs. 31g (ET 2.5). This concerns horizontal mass 1:1.
Also the bearings outer tube is considerably heavier. This concerns compatibilty with sprung subchassis.
Mid 80's there were a lot of english (and swiss/german) tables around, with rel. lighweight sprung subchassis. Minimizing mass was important for compatibility.And keeping the spindle (and horizontal) mass low was important for optimized MM & MC compatibility. (If only not to stand too much out in the theoretical rain concerning "much too high horizontal mass").
The high pressure bearing increased stiffness of the bearing, and the larger spindle increases stiffness of the bearing by an additional factor of 2.5! The ET2 bearing is stiff to begin with (it's not the "intuitive" air cushion one imagines), but the ET2.5s large surface high pressure bearing is even stiffer by (guessed) almost an order of magnitude.
Practice shows that even the high compliance B&O MMC1 "likes" the heaviest ET2.5 configuration, without getting hickups.(as it "likes" a longhorn stabilizer even though the coupling of the cantilever to the body is of rel. low stiffness.)
I think the reason for the ET2 spindle design was
a) it was quite brillant with any cartridge (and still is).
b) the ET2 spindle is ca. 23 g vs. 31g (ET 2.5). This concerns horizontal mass 1:1.
Also the bearings outer tube is considerably heavier. This concerns compatibilty with sprung subchassis.
Mid 80's there were a lot of english (and swiss/german) tables around, with rel. lighweight sprung subchassis. Minimizing mass was important for compatibility.And keeping the spindle (and horizontal) mass low was important for optimized MM & MC compatibility. (If only not to stand too much out in the theoretical rain concerning "much too high horizontal mass").
The high pressure bearing increased stiffness of the bearing, and the larger spindle increases stiffness of the bearing by an additional factor of 2.5! The ET2 bearing is stiff to begin with (it's not the "intuitive" air cushion one imagines), but the ET2.5s large surface high pressure bearing is even stiffer by (guessed) almost an order of magnitude.
Practice shows that even the high compliance B&O MMC1 "likes" the heaviest ET2.5 configuration, without getting hickups.(as it "likes" a longhorn stabilizer even though the coupling of the cantilever to the body is of rel. low stiffness.)

