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

Showing 3 responses by nandric

From the German HIFI Magazine 'Das Ohr' (1984!) I learned that the pivot-spindle distance should be 231,5mm for the optimal geometry(64S+64FX) I use this geometry since and rcentlyordered by Yip his Mint Tractor fo this distance + the SP-10 spindle 'thickness'. Those seem to differ by different TT's.
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.
The problem by integrated headshells is that one can't move the
stylus to ''optimal position'' as is the case by ''ordinary headshells''.
Even the FR -7 kinds have different cantilever length which imply
different stylus to pivot distance . So the only way to get correct
geometry is to move the arm in its base to correct distance in
the sense of stylus to pivot distance.