12 inch tonearms

Hi DMgrant,

I applaud your quest for knowledge and musical truth. I cut the following comments from the Schroeder FAQ's section of my website ... not to deter you from your quest, but to add another point of view.

I think you should look at a second good arm, and not limit yourself to a 12" one ... unless you have specialized needs (or curiosity, which I obviously applaud). With that preamble, here's a portion of my "first impressions of a Schroeder" page which is linked to from my Schroeder FAQ's page:

As I've gained experience with more quality pivoted tonearms in the last 18 months, I have arrived at the conclusion that most of what we describe as tracing distortion in pivoted arms is in fact the arm chattering in the groove. I'm certain that my positive experiences of 12 inch tonearms has more to do with the quality of these arms and not with their length - it ain't the meat, it's the (absence of) motion (resonance).

I am in complete agreement with Frank Schroeder - that by stabilizing the cartridge in the groove (taming resonances) the need for longer tonearms is obviated. Build a good 9" arm and you don't have to go longer. Certainly there are specialized requirements for long arms, among them are increasing mass for low compliance cartridges as well as the use of oversized platters, but 12" arms are not required for sonic reasons. I have become a true believer.

Cheers,
Thom

Thom, Makes good sense to me- easier to keep the cartridge in line at 9 inches than 12. Mostly the quest is based on curiosity and variety.

Does this mean that most of the nine inch arms can't do it as well as 9 inch or that, under the Schroeder theory, most simply choose to make 9 inch arms?

Gee, I was hoping someone would be so kind as to be the guinea pig for a 12" DaVinci. ;)

Hi,
The SME 3012 is another example of a 12"er that beats its 9 and 10" siblings. Not necessarily because of the reduced tracing error(that too, if set up perfectly), but because of the heavier counterweight that results in a heavier load on the knife edge bearings(reduced relative movement between knife edge and "cup" when exited by energy fed into the arms structure).

A word about tonearm geometry.
A 12" arm that has been set up with the overhang beeing 0,5mm too short(I've seen WAAYY larger misalignment at dealers and other "experts") will yield a larger max. tracing error than that of a precisely set up 9" arm.
If in doubt, it is better to have the stylus a little(no more than 0,5mm in front of your alignment grid/crosshair. This referring to an alignment gauge that adheres to Baerwald nullpoints.

The longer the arm, the more crucial it becomes to get overhang and(even more difficult to nail) offset angle spot on. For an offset angle that is a mere 0,5° too large(think misaligned cantilever), the resulting error once again will make the theoretical advantage mute.

Perfect alignment for a 12"er yields max. tracing error related distorsions of 0,45% between null points, 0,5° more causes 0,76% distorsions(compared to 0,6% for a perfectly aligned 9.4"er).
Analogous to the overhang, rather err to an angle too small. The tracing error related distorsions will then increase towards the innermost usable area only. Not too many records with modulations that close to the run out groove. Best to get it perfectly right off course...
Make sure to disengage antiskating or lower the stylus so that is just about stays clear of the template/gauge. The Antiskating will skew the cantilever, making it impossible to get zenith/offset angle right.
Recheck after cart has 100hrs on its heel.

To sum it up, spend time and use proper alignment tools or you're waisting your money on megabuck arms and carts.

Cheerio,

Frank Schröder