The Moerch DP-6 is an anomaly, in that the consensus is that its 12" iteration is a better arm than the 9" version. Equivalent mass 9" and 12" Moerch arms sound different. I have some thoughts as to why, but no time to elaborate on this.
In general however, I would agree with Raul in that it ain't the meat, it's the motion
that length is just one attribute contributing to fun-factor. Cartridge compatibility and a host of other matters come into play.
I used to look at Bob Graham's white paper (where he advocates a 9" length as being the best optimal solution) with a jaundiced eye. From the perspective of the importance of optimizing tracking error to the exclusion of all other parameters, my experiences with Grahams, Triplanars and Schröders have brought me over to Bob's camp.
FWIW, Frank Schröder is also in the 9" camp
again, because there are so many different issues contributing to making a competent, musical arm that satisfies the goals of getting the most music out of your record collection, with length (and any inherent tracing distortion advantage) being only one of them.
Again, the smart money has it that in the Moerch world, 12" is the way to go, but know that in the opinion of many, you will not be learning anything about 12" arms in general, but rather about the Moerch in its 12". If you are curious about the Moerch, then this is the path many have taken.
Are there cartridges which will work best with the 9" Moerch? I suspect so. The above comments are based on tribal knowledge and not cast in stone.
Cheers,
Thom @ Galibier
