12 inch Graham Phantom

LOL. Try and keep this under control. This thread is well on its way to be deleted.

I think Peter at North Audio also carry some long ones.

I have also seen some >18" ones made with exotic african wood material.

o.k. - back to the mere prosaic world of analog-highend audio.
If the rigidity of a given tonearm AND its moving mass AND its ability (if there is any ability) to transfer energy is NOT diminished by the increased length of the armpipe - then the advantage in minimized geometrical error will show off in "improved" (whatever that is..) sonic presentation.
So - if all strong points of a given tonearm-design are preserved while increasing its length - and thus decreasing its geometrical error (tangential...) - then the longer version will be the "better" version.
As with everything in our physical sphere, there is a "window" or "frame" of superior function under the given mechanical circumstances. Below 9" the error in a pivoted design becomes too large to allow serious high-fidelity sound (at least to my ears). Above 12-13" there will be very few plinth/turntables around to accommodate a tonearm of that length. Furthermore the further minimization in tangential error will be so little, that it won't show off any more in real-world set-ups.
Between 9" and 12" there is a significant improvement in tangential error and the toenarms of that effective length still do show reasonable rigidity and moving mass.
Compare the 12" to the 10" versions in tonearm-designs like the SME, the Ikeda, the Phantom II, the Fidelity Research FR60s-series. While the differences are subtle, they are there. Clear and in all the different designs of the tonearms just mentioned, they are showing in the same direction.
I like it when physical laws and geometry show their impact in analog.
Not all is myth or voodoo.

I remember reading somewhere that mistakes in setting up a 12 inch arm as compared to a 9 inch arm will be more "severe". I forget where I read it but it seems to make sense. A 12 inch arm is less tolerant of poor setup than a 9 inch. Also I find the the Lofgren A vs B vs. Stevenson alignments cater to different arms differently.

Dgad, ...
10-03-10: Dgad
I remember reading somewhere that mistakes in setting up a 12 inch arm as compared to a 9 inch arm will be more "severe". I forget where I read it but it seems to make sense. A 12 inch arm is less tolerant of poor setup than a 9 inch.

.... interesting.
You will supply the geometrical background for this statement ?! At least for this poor educated soul of mine it is not immediately apparent, why "mistakes in setting up a 12" arm as compared to a 9" arm will be more "severe"...".
This rather seems one of those "high-end-audio-only laws of physics" probably stated by one of the self-promoted deans of analog-audio-MIT
Please clarify.

Derto/Dgad: on increased potential for set-up error for longer arms, I remember seeing that too - in one of the mags, maybe Dudley in the last 3-4 mos, maybe when he did the Schick (sic) arm. Or it may have been one of Fremers asides...but I have in my head, Dudley.