Hiho, thanks for your comments. Regarding the alignment precision of the stylus locator system described above, I can assure you that it will get you very close. To use your ball park analogy, if the ball park stadium were a bulls eye with the pitching rubber being dead on center, this system will put you on the pitchers mound. From there, cartridge manufacturing variation will require you to find the rubber by ear.
The Centroid does have VTA adjustment, however it cannot be done on the fly. The set screw you see on top of the arm adjusts the the arm body position on the pin of the bearing (and is quite stiff to turn) so adjusting VTA does not alter the pivot point relative to the record plane. The distribution of the mass relative to the pivot point is critical in a unipivot and indeed if distributed incorrectly can exacerbate any resonance or record warp issues the arm has to deal with. For instance, if deliberately disturbed, the Centroid quiets down extremely fast due to the inherently stable nature of the distributed mass and it does not continue to rock. The azimuth is adjusted using a stainless set screw set into the side of the counterweight. The set screw is rather large, is set up high near the pivot point, and buries very deep into the weight . Like the heavy counterweight itself, it requires very little movement back and forth to accommodate any azimuth adjustment required. Damping is provided by using a silicone fluid pool with a variable height set screw to provide a wide range of damping effect, or none at all. On the Centroid model that mates to a Spiral Groove turntable (called the SG Integrated) the fluid pool is integrated (machined) into the arm board and the set screw is threaded into the arm body. For Centroid arms not bound for a Spiral Groove table, the Centroid Universal Integrated arm will have a very lightweight but stiff control plane that simulates the Spiral Groove armboard in function, providing the damping fluid pool, arm rest, mechanical cueing device, anti-skate support, and RCA block. The Universal Integrated is designed to be light enough to be mounted on lightly sprung decks such as the Linn LP 12. The Universal Integrated will mount with a single bolt and will have the facility to adjust the pivot point height to match the record plane of the turntable while still allowing for independent VTA adjustment, albeit it not on the fly. Mounting jigs and tools will be provided to dealers to ensure that the pivot point will be accurately positioned at the record plane of the particular turntable being worked on. The application of anti-skate force can also be a problem for a unipivot. The Centroid anti-skate is applied with a hanging weight connected to the arm body. Where the thread connects to the arm body is height variable so no matter where you have set VTA, you can always position the point at which the anti-skate applies force on the arm is centered at the pivot point and will not tug the cartridge out of azimuth. Additionally, the curve that the string follows is such that it tracks with the variable skating forces across the record and applies an equally variable and therefore uniform anti-skate compensation all the way across the record, which I think is pretty cool.
