Time to choose: Baerwald, Lofgren, Stevenson ?

sampsa55

If the cartridge is aligned as designed by manufacturer, then the cartridge is straight in the headshell.

Oh no, that's not at all necessarily the case. As others have pointed out, there's often a slight misalignment of the cantilever within the cartridge itself. Proper cartridge alignment aligns the cantilever to the record, and not the cartridge to the headshell. This is where mirrored alignment gauges - such as the WallyTracktor - really excel.

Thom, The issue of doing the twist (Chubby Checker, where are you now that we need you?) has most to do with using Baerwald or Lofgren with a tonearm designed for Stevenson. This issue therefore only or mostly comes up with vintage tonearms of the kind that you usually do not deal with. In my case, it’s a Dynavector DV505. To set up the DV505 for B or L, one has to twist the cartridge inward (such that the front end of the cartridge is skewed toward the spindle side of the headshell) quite a bit. And of course, when I use the term "cartridge", I am referring to the cantilever, which is what counts, regardless of the fact that some cartridges do not come to us with precisely aligned cantilevers. Ideally, the cantilever should move in an arc in the vertical plane; it’s possible that when the plane of that arc does not align with the vertical plane described by the tonearm bearing, vector forces on the cantilever would not even out. I actually suspect this is a real issue that may be confined to the DV505 and other DV tonearms, where there are two discrete bearing systems, one vertical and one horizontal at play. In these tonearms, the vertical bearing cannot move horizontally to compensate for such a misalignment of the arcs. Maybe that is why I heard distortion as a result.  Maybe it's a red herring for more conventional tonearms.

Oh no, that's not at all necessarily the case. As others have pointed out, there's often a slight misalignment of the cantilever within the cartridge itself. Proper cartridge alignment aligns the cantilever to the record, and not the cartridge to the headshell. 

As, lewm already indicated, that doesn't change the conclusion at all. If you align by the cantilever, then the cantilever (rather than the body) will be aligned straight in the headshell and will remain so in any arm if you use the alignment that the tonearm was designed for.

Dear @sampsa55 :  """   I align the cartridges based on the alignment the tonearm was designed for. Since most of my tonearms use removable head shells and were designed for a 52mm distance from the head shell connection to the stylus... """

that's true only if those tonearms has the same effective length.

Remember that the Löfgren calculations ( he was the first to do it and all the other kind of alignments starts by his equations. ) begin with the input know parameters:
tonearm effective length, inner most groove radius and outer most groove radius. This is the foundation of the alignments that must be untouched for the calculations.

From those 3 input parameters we calculate: offset angle, overhang, both null points and distance from the center of tonearm pivot to the center of TT spindle. If we move the overhang we need to move the tonearm mount distance in order to mantain distortions at minimum for the choosed alignment calculations.

Understanding all those we can have a " personal " alignments changing the effective length or any or both radius.

As I posted here in the tonearm/cartridge set up the name of the game with the choosed alignment is: accuracy on that set up.

Regards and enjoy the music,
R.

Dear @sampsa55 : """ I align the cartridges based on the alignment the tonearm was designed for. Since most of my tonearms use removable head shells and were designed for a 52mm distance from the head shell connection to the stylus... """

that’s true only if those tonearms has the same effective length.

Ah, no. The effective length of the tonearm has nothing to do with this. You can have tonearms of very different length that are still designed to have the same 52mm distance from stylus to tonearm connection or tonearms with the exact same length that are designed for a different distance (e.g., 50mm) from stylus to tonearm connection.

Again, think about the SPU: it can be used in short and long tonearms.