Dover's geometry is *almost* correct. The longest p-to-s distance occurs when the armtube is level. Any change (+ or -) away from that shortens the p-to-s distance.
Like Dover, I'm also unaware of any tonearm besides the ET2 that self-corrects for this. That's right, every other tonearm that adjusts height gets this wrong. To get it right, the bearing end must move up/down on an arc of constant radius that's centered at the stylus point.
As to whether p-to-s distance "needs" to be adjusted for each change in arm height, that's another matter. Shortening the p-to-s distance effectively moves the null points of your alignment, which alters the mistracking distortion curve. Whether and how much this is audible depends on a host of variables, including characteristics of the particular LP being played.
I don't worry about it, largely because, as a non-ET2 owner, there's nothing practical that I can do about it!
Like Dover, I'm also unaware of any tonearm besides the ET2 that self-corrects for this. That's right, every other tonearm that adjusts height gets this wrong. To get it right, the bearing end must move up/down on an arc of constant radius that's centered at the stylus point.
As to whether p-to-s distance "needs" to be adjusted for each change in arm height, that's another matter. Shortening the p-to-s distance effectively moves the null points of your alignment, which alters the mistracking distortion curve. Whether and how much this is audible depends on a host of variables, including characteristics of the particular LP being played.
I don't worry about it, largely because, as a non-ET2 owner, there's nothing practical that I can do about it!
