"S" shaped tonearm ?

The S shape arm is an inferior design.

It has been mathematically proven that the minimum tracking error of a pivoted arm is given by the Baerwald equations, which require a headshell offset angle.

There are 2 obvious ways to obtain a headshell offset angle:
1. Angle the headshell relative to the armtube
2. Bend the armtube into an "S".

In the field of Strength of Materials, which is the study of shapes and their response to stress (and has nothing to do with actual materials, so the name can be misleading to non-engineers), it is mathematically proven, and experiements back this up, that the deflection of a column is proportional to its length given other equal parameters. In Vibrational Analysis it is proven that longer beams of the same cross sectional area will suffer far greater vibrational deflection. Therefore, in both the static and dynamic conditions, a shorter armtube would be superior if one's goal is neutrality.

Since the S shaped armtube is inferior in both strength and vibrational analysis, with no other advantages, there is simply no reason to do this other than reasons of aesthetics, ease of fabrication, or nostalgia.

Anyone making a case for an "S" shaped armtube being superior is showing that either he has no technical understanding of the matters at hand or does not have a goal of neutrality for the tonearm.

The current "high end" tonearms i.e. Schroeder, Graham etc. are all straight and relatively short arms.

I always thought that S shaped arms started disappearing around the time MCs became the rage and that it was discovered that you needed a more rigid arm tube for MCs than with light and compliant MM or moving iron designs, so that extra material to make it stiffer and extra material to keep the S shape just wouldn’t do.

I remember the SME model that was S shaped with a titanium wand and I think it was no slouch teamed with a compatible cart.

I like the way you seem to think that everything made now is better than everything made then. I guess one does fall into that trap when one is a monger.

Well, here are my guesses - form followed function.

Until sometime in the 50s, most arms were straight. Then, when the importance of offset angle became better known, arm manufacturers designed "S" or "J" arms to achieve this angle. Also, remember at this time it became common to have a removeable headshell, something easier to implement with a S or J arm if offset was to be maintained. Next, in the mid-70s high compliance cartridge designs became more popular, thus requiring low mass arms. It was easy to see a straight arm would have lower mass, all other things being equal, so many lower mass straight arms with offset headshells were introduced. Then by the late 70s/early 80s, MC cartridges became more popular. Being lower in compliance (on average) they required higher mass arms. This time, realizing straight armtubes were easier and cheaper to build, manufacturers continued with straight arm designs but with higher mass, a practice continued to the present.

If you read fellow 'goner Raul, you may see that sometimes straight arms work best, sometimes S or J arm are a better match. Similarly, a fixed headshell should not automatically be assumed to be superior. In reviewing Raul's comments, you'll see that sometimes the surprising arm/cartridge match is the one which works the best.