i think that @dcc had his SAT adjusted on a different (than SAT modified Löfgren ) tangential curve and has reported an improvement. I believe that @silviajulieta is right
Null points are one of the output parameters in the alignment calculations. Löfgren research/studies let him to developed the Löfgren A and Löfgren B equaTIONS TO ALIGN ANY CARTRIDGE WITH ANY PIVOTED TONEARM it does not matters the arm geometry/shape.
So I don't care of them any more in this specific issue, what I care about is to know the manufacturer effective length spec and that's all we need to make the alingment.
I installed a SAT CF-09 tonearm and used manufacturer's protractor. I listened to a lot of records with it and had no problems with distortion. but I should note that they were all Analog Productions issues which were not cut close to the label. so standard Lofgren A may be better with SAT and old records.If I was a SAT owner I will go for Löfgren A ( as SAT manufacturer says. )
Japan is way different because for unknow reasons ( at least for me because their choice has no sense. ) they ( almost all. ) choosed Stevenson A instead that Stevenson B ( that's exactly same as Löfgren A. They did it especially in those great vintage designs they manufactured. ) that has no single advantage for what we listen in our room/systems.
you only need pivot to spindle distance (P2S) of a tonearm for your calculations not the effective length (EL).
About the japanese tonearms your take is not exactly as you said. Examples manufacturer specs:
SAEC 506. : 9mm, 407 12mm.
Denon 309 14mm 308 12.5mm
Exel 1000 17.25mm
FR66 12mm
Stax 13mm
Toho 14mm
Wilson calculated what alignment of the replay components would minimize LTE across the disc that this would also minimize the resulting distortion. To achieve this, he found, the radius of the stylus (needle) arc had to be greater than the distance from the arm pivot to the center of the disc, by a distance that today we term the overhang; and the pickup cartridge had to be twisted relative to a line joining stylus to arm pivot by an angle termed the offset. This overhang-plus-offset geometry, Wilson's great contribution to arm/cartridge alignment, is still used today, even though his equations for calculating the two parameters have been superseded.............
If we assume an arm effective length (that is, the horizontal distance from stylus to arm pivot axis) ...."
He never talked about P2S as Löfgren neither did it.
The P2S distance is not an output of the calculations but is just the difference between the input effective length with the output overhang parameter. ""
there said: ORIGINAL and at the end " The P2S distance is not an output of the calculations "
MINTLP dedicated protractor asked to the tonearm owner for the P2S and why is it this way? because normally the owner tonearm it's already mounted at a very specific P2S and MINTLP wants to make things easy for the customer. Anyway results are the same after calculations.
you say P2S is not mentioned. please read underlined sentence from your post
Technics 15mm almost all arms
but it's a better and normal way to start with P2S
Dear friend: that statement is incredible. My native language is spanish and my english is to bad and I make several mistakes about. I already fixed because the word I wanted to post was USED but your post is incredible too not only because you had no patience with me about but because the main issue was not what you posted but that the Lófgren input parameters in his equations were 3 and no one of them was P2S. Maybe you don't like it that I posted your misunderstood about.
I was the same as you. You're really going to like AM. Version 2 is meant to be coming out very soon (currently being beta tested). Richard has always said version upgrades will be free to existing users, but as there is more functionality we might need to pay for new test LPs.Thank you. I am looking forward to using it to optimize my setup. Currently have a SMARTractor, SMARTstylus, Wallyskater, and Fozgometer as my primary setup tools. Hoping AM helps guide those final adjustments I continue to question and tweak.
Rick
I predict another Fozgometer goes up for sale shortly.I was the same as you. You're really going to like AM. Version 2 is meant to be coming out very soon (currently being beta tested). Richard has always said version upgrades will be free to existing users, but as there is more functionality we might need to pay for new test LPs.
Well one could simply set vertical tracking angle by ear using the records he usually listens to. That would seem a better method than using a test record and measurementsa test record that is a different thickness.
i’m just speculating as I’ve never used this program.
It’s better to power ART Phono from computer via usb cable. It’s the recommended method for AM measurements.Thank you for the reply. It does not ship with a wall wart but I have noted some “optional” ones being sold for use with it. Just thought I would reach out for confirmation that it was not a preferred method to power the ART phono plus.