Fidelity Research FR64s Headshell dilemma

they disappeared not due to geometry but due to CD era.
https://www.analogplanet.com/content/saec-again-producing-classic-double-knife-edge-bearing-tone-arm

I have experimented with my 308SX they weird geometry works better that Stevenson. I have tried to move it to Stevenson although it tracks worse than with SAEC weird one, I am not expert like Raul but I really like test disks :)

Dear @bukanona : please correct me if I’m wrong. I just finished to analize what SAEC did it for the cartridge/tonearm alignment on each of his models and I took as an example your 308SX.

Thank’s that you brought out here the SAEC tonearm alignments finally I think I understand what they did it, at least with your model and my 8000 one.

For me is an was not so easy to discern this unique tonearm alignment data " novelty "/manipulation and maybe it’s the same way for almost all gentlemans here and elsewhere.

Now what they did it, that seems to me with out be totally sure ( only SAEC people of those times know about. ), with your 308SX is in the next link. I took as EL 240mm, overhang 5mm and offset angle 12° that are SAEC specs, I hope is rigth. Ok. they took both: must inner groove radio and must outer groove radius totally out of the LP recorded surface. Both around 50mm ( a little lower than that but the calculator does not permits lower " number ". ) that using the vinylengine calculator gives as result those parameters values ( almost there. ):

https://www.vinylengine.com/tonearm_alignment_calculator_pro.php?arm1=Arm+1&l1=el&a1lv=240&a1=la&oh1v=&oa1v=&arm2=Lofgren+A&l2=el&a2lv=240&a2=la&oh2v=&oa2v=&arm3=Lofgren+B&l3=el&a3lv=240&a3=lb&oh3v=&oa3v=&arm4=Stevenson&l4=el&a4lv=240&a4=st&oh4v=&oa4v=&rs=12&rsv=&og=cus&ogv=50.001&ig=cus&igv=50&cal=y&submit=calculate


that calculator was not made it to that kind of " novelty " so we can’t have the diagrams/graphics ( looks like tracking distortion/error gone very high .) about but we almost there.

Anyway, a pain in the ass to align a cartridge with the SAEC specs. As I told you what I use it in the 506-30 and 407-23 was Löfgren and this is what you can do too because for me wroks just fine and with no troble of any way.

Regards and enjoy the MUSIC NOT DISTORTIONS,
R.

Using other calculator it confirms that SAEC made it a " deep " manipulation with the must inner/outer groove radius.

In this other calculator I used 37.4mm and 66.9mm and the off set angle and overhang coincide with SAEC specs.

So manipulations/combinations of both equations groove radius will change everything and we can be " everywhere " doing that. Go figure.

R.

Of course, no diagram/graphics in teh vinilengine calculator because the null points are inside the LP label not in the usable LP surface.

R.

Dear friends: The whole cartridge/tonearm alignment subject is really important to understand it to stop that after market items follows taking advantage of our low level knowledge and I say that because that's exactly the history of after market protractors and " developed " better " kind of alignments " when in reality that does not gives true advantages.

SAT comes with its own kind of alignment, VPI the same, already looks SAEC, all japanese tonearms, uni-din and many more.

All that diversity only makes to us things more complecated when we don't understand in precise way the whole subject and we can look at the thread list in this forum and we will found out " hundred " of threads asking on that alignment subject and looking for the best.

In reality does not exist the best, in any kind of alignment exist compromises. 
No one of us needs something different to Löfgren A/Baerwald or/and Löfgren B ( of course that the stupid Setevenson one is totally out of question if we are serious on the main subject and really cares about MUSIC. ). All the other alignments can't gives us a true advantage that we can detect.

Please read this where I show what is happening with tracking distortion levels inside Lófgren alignment. I took LP grooves information away of null points because as a nearer we are of null point is totally and extremelly imposible to detect any differences between recorded information in the grooves. This is only and example with a tonearm with EL 254mm.:

tracking distortion between 90mm. and 100mm ( 1cm. of LP surface recorded area. ) is 0.12%.
Maybe some of you can say: hey I can detect that tracking distortion level difference !. As I said maybe, I know I can't do it.

Now, that level of distortion is at 90mm-100mm but when playing an LP the cartridge rides the grooves with continuty: one after the next and so on.

The difference in tracking distortion level between 90mm and 91mm. is 0.008% that's the difference between: 0.553% and 0.545%.

Now, whom of you can detect 0.008% tracking distortion levels differences?. Obviously NO ONE CAN.

It's not only that the differences are so low but that the MUSIC we are listening are pércieved by us in a continue way what makes impossible to detect those kind of tracking distortion levels.

So why we oftencan post something like this: that the SAT alignment sounds better that in the same tonearm we align it with Löfgren one or uni-din or Cotter or VPI/Cotter or Clearaudio are better alignments when in reality are not.

And exist other issue when we are trying to make evaluations/comparisons between those kind of cartridge/tonearm alignments:

each time we change from one alignment to other at least we need to change the cartridge position and after that we need to res-set all cartridge/tonearm parameters: VTA/SRA, VTF, Azymuth, AS and the like and is imposible that with the new cartridge alignment the tiny stylus tip parameters will coincide with the precise and exactly same accuracy that before the change to the new alignment.

That's why I say that Löfgren A/Baerwald or/and Löfgren B is all what we need no maters what.

Don't you think? or exist something that I'm not seeing because ceratinly I can be wrong but today this is my take and invite you to think about and post your thoughts on the overall subject.

So wich protractor need we? I think that MINTLP is more than enough and with the need it accuracy for a tonearm, if we own more than one tonearm then we need additional MINTLP protractors: each for each tonearm. Why sped more money for any other protractor? makes no sense to me. Of course that we can use the self tonearm protractor if is totally accurated ( at least at the MINTLP level. ) and no Stevenson there.

Regards and enjoy the MUSIC NOT DISTORTIONS,
R.