looking at upgrading my tonearm from a triplanar

Had Triplaner TW 10.5 is much better.

Ralph, your mention of the hardness of the bearings in the Triplanar brings to mind a couple of questions for me. Could you give us your design engineer's perspective on the following?

- What is the significance of the hardness of a tonearm's bearings? At the tonearm weights involved, that alone wouldn't seem to be important.

- On the other hand, beside the bearing design itself, two bearing characteristics would seem, at least conceptually, to matter a great deal:

1- The bearing's ability to transfer mechanical energy out of the arm tube and into the mass of the turntable
2- The smoothness of the surface of the bearing material, for lowest friction.

another contender under $10k to seriously consider is the Durand Kairos; which has the composite arm wand.

if you want to upgrade from the Talea MkII it would be a nice step up while retaining that same sonic perspective.

- What is the significance of the hardness of a tonearm's bearings? At the tonearm weights involved, that alone wouldn't seem to be important.

The hardness is important- the more the bearing has the less sticktion. The size is also important- the smaller the bearing the less sticktion. Jeweled bearings (which are very hard) are unfortunately also very easy to damage and often don't survive adjustment at the factory, which is why they are usually adjusted with a little slop. If you over-tighten them they are damaged instantly. So a hard metal bearing is essential for longevity in the field. It is the failure of arm bearings that is why the arm may need to be readjusted over time.

- On the other hand, beside the bearing design itself, two bearing characteristics would seem, at least conceptually, to matter a great deal:

1- The bearing's ability to transfer mechanical energy out of the arm tube and into the mass of the turntable
2- The smoothness of the surface of the bearing material, for lowest friction.

The bearing ideally should not have to transfer any mechanical energy. If it does, this means that the arm and cartridge are mismatched (effective mass is incorrect). What the bearing should be doing is allowing the arm tube to move with the position of the stylus but otherwise simply keeping the cartridge in proper locus so that the stylus' set of angles with respect to the groove of the LP is maintained. The bearings IOW serve no damping properties whatsoever: this would run counter to their mission.

The bearing ideally should not have to transfer any mechanical energy. If it does, this means that the arm and cartridge are mismatched (effective mass is incorrect).

Strongly disagree. The effective mass/compliance relationship tells us only how a cartridge/arm behave when considered as a spring-loaded system. It tells us nothing about how they respond to internal vibrations.

No cartridge is 100% efficient as a transducer. All cartridges respond to cantilever movements by:
1) converting some of this mechanical energy to electrical signal;
2) converting some of this mechanical energy to heat; and
3) not converting some of this mechanical energy at all, which remains in its original state as physical vibrations.

The mix of 1, 2 and 3 is unique to each cartridge and varies according to frequency across the entire audible band (and beyond). The portion that remains as mechanical vibration may propagate through the cartridge body, into the headshell, into the tonearm and beyond.

Depending on frequency and phase, some of these vibrations will be reflected by material boundary layers, potentially setting up internal resonances. (This is very audible with certain cartridges, like those ZYX models with a blue ball on the front.)

Other vibrations may be dissipated as heat as they travel through various materials in the cartridge body, headshell or tonearm. (Well engineered wood tonearm wands are especially good at this.)

Still other vibrations may travel the length of the arm and reach the bearings. At this point, Bpd24's question comes into effect... how will the bearings respond to this?

Some bearings (Schroeder, Well Tempered) are designed to absorb/dissipate such energies. They do so to a greater or lesser degree, but inevitably suffer some loss in precision and dynamics. Other bearings (Triplanar, SME, other fixed bearings) may pass some energies into the arm base, while reflecting others.

No single bearing parameter (including hardness) is sufficient to predict the behavior of this highly complex process, which occurs across a nearly infinite number of frequencies. In particular, the compliance/effective mass relationship has no relevance in this area.