Question on FR 66s

Hi Henry, I use the protractor which is supplied by the manufacturer of my turntable, Acoustic Solid. It is a Feikert like protractor.
Using the DB Technologies for the off set angle check at the null points.

Chris

Dear vinyl-o-philes, it is perhaps a bit late to chime in but I haven't noticed this thread until now.
For the FR 66S enthousiasts: I don't want to be the fly in the ointment, but some experts (like Jonathan Carr of Lyra) say that the FR-66S rings as hell.
What is your response to this statement?
I also have a technical question for you. I own a FR-66S myself, which I'm using with a SPU Anniversary 85. The length of the SPU is 52 mm instead of the 50 mm recommended by Ikeda.
So the effective length of the tonearm is 2 mm above the specified length and the overhang is more than 12 mm as specified.
What should I do to get the right geometry: leave it this way or adjust the S2P distance to 297 mm (295 mm is specified)?

Chris

Hi Lew, I believe Jonathan Carr has a point here. Sometimes I do hear something that you can call ringing when comparing vinyl playback with digital.
Of course it is not a proof this is due to the tonearm only because many other things can also contribute to this phenomenon.
Moreover, I find the bass reproduction is not state of the art: it is rather pompous and lacks definition and slam.

Chris

Hi Bill, thank you for your recommendation. So if I'm correct the specified P2S distance is not a "holy grail" that cannot be touched by mere mortals?
More important is the correct geometry at the null points (that is that the cartridge is parallel to the grid on the protractor)?

Chris

Hi Bill, thank you for your recommendation. It appears to me that the manufacturer specified S2P distance is not some kind of "holy grail" that cannot be touched by mere mortals.
According to an geometriy calculator as supplied by Vinyl Engine you can calculate the distortion if the geometry is changed.
If I change the S2P distance to 297 mm (instead of 295 mm) and the overhang can be kept at 12 mm, I would end up with reasonable distortion. But you will deal with other null points!

Chris

Bill, John, Lew and others, I would like to have your opinion about the following calculations I made regarding the geometry of the FR-66S with a SPU (52 mm length). Please correct me if I'm wrong.
The effective length of the FR-66S with needle to arm distance of 50 mm is 307 mm.
Draw a imaginary line (line 1) between the needle and the pivot, which is the same as the effective length.
Draw another line (= line 2) from the needle, parallel to the head shell.
Between line 1 and line 2 there is an angle, which is the offset angle (16.8 degrees for the FR-66S).
So the projection of line 1 on line 2 is cosine of 16.8 degrees * 307 mm = 293.9 mm (right triangle).
293.9 mm + 2 mm (because the length of the SPU is 52 mm) = 295.9 mm.
The new effective length will be: 1/cosine 16.8 degrees *295.9 mm = 309 mm.
If we want to have an overhang of 12 mm, the P2S distance would be: 309 mm - 12 mm = 297 mm.

Chris