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Correct alignment for Fidelity Research 64fx/SPU?

Hello,

I've recently paired SPU Spirit with FR64fx (& additional counterweight).

FR64fx is mounted at 230mm pivot to spindle distance on my Garrard 301.

I currently experience a light distortion and mistracking. As I tried the SPU before on almost ad hoc mounted 3012 and that sounded technically correct (though not as convincing as with FR64fx in terms of emotional performance), I'm pretty convinced I will need to realign the tonearm.

I would appreciate any info related to an experience of 64/SPU users here, which would differ from a usual 230m PTS alignment. Also, I keep on reading that Stevenson alignment would be preferred, is there any explanation why so?

Basically I need to make a good decision as I have no armboard - whatever decision I make I will need to get a new top board with a new hole for a new alignment.

Many thanks!
anubisgrau
lewm
6,770 posts
 
Question to those who use SPU:
Isn't there something "funny" about this cartridge, such that the tonearm has to be adapted for proper alignment, or something like that? I think it has to do with the distance between the rear of the cartridge body and the stylus tip.
nandric's avatar
nandric
3,263 posts
 
Dear Jeff, Regarding the 'original question'. I prefer to
put this question otherwise. Not as 'what is the correct
alignment' but as 'what is the optimal geometry ' for the
64 series? After all both , Stevenson and Bearwald should
be considered as 'correct' but, as I mentioned in my reference
to 'Das Ohr' Magazine and you to Dertonarm the
'optimal distance' should be 231,5 mm. But this means
Bearwald geometry as well the assumption that Bearwald is
'optimal' and consequently that Srevenson is not.
dkarmeli
332 posts
 
Lewm, the SPU comes in its own fixed headshell so don't have ability to change the tracking via the headshell like a standard cartridge. In case of the SME the base is also adjustable but not with the FR. In this case you need to move the arm hole on the board for optimum tracking angle.
jeff1225
147 posts
 
The set up instructions for the FR 64S and Ikeda 345 state a 50cm distance from the stylus to the headshell mount. Ortofon SPU's have this 50cm distance so there shouldn't be an issue if the arm is set up properly from the beginning.
lewm
6,770 posts
 
"50 cm" = ~19.6 inches!!!!
Probably you meant to write "50mm", but I wouldn't know for sure.

I thought I read in one of Art Dudley's commentaries that the SPU required special mounting and/or tonearm adaptation. Dkarmeli's post suggests I was correct; the cartridge directly mates to the headshell mount on the arm wand. So I imagine you cannot either twist the cartridge in its mount to achieve, say, Baerwald geometry, nor move it fore and aft so as to achieve correct pivot to stylus distance. You have to take into account its stylus to mount distance when siting your tonearm pivot.
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