Skeletal vs Plinth style turntables

CT, I am glad someone appreciates my sense of humor.

Regards, all: I'm quite impressed by the depth of experience reflected in the comments above. Except that Gibson fellow. He's a hack and prone to gross exaggeration.

Viridian suggests that the removal of the tonearm from the plinth tends to remove plinth based excitations from the tonearm.

Atmasphere proposes precise coupling of the platter bearings and tonearm base, LewM seems to agree.

Richardkrebs writes: "A skeletal design makes this goal more difficult to achieve since we are introducing the support structure, shelf, platform, into the equation. It effectively becomes the plinth. Related to this is the minimization of joints and material changes in the platter-arm loop."

Ct0517 (hi, Chris) shares this experience "An exercise of Function over Form for me. The tonearm attached to the POD is a leading example of this.
If for some reason one "hears" a mismatch in resonances, the ET2 (tonearm) provides resonances tuning capability."

Halcro: "I simply use my ears and listen to actual examples BEFORE I blindly theorise." Henry implements a tweaked wall mounted shelf and considers it a plinth. There has not yet been proof offered of unwanted movement in the spindle/pivot dimension but neither should one deny the possibility.

These things are known for certain:
The greater the mass, the lower the vibrational frequency. Beams (tonearms) with a lesser mass vibrate at a higher frequency.

Vibration takes place when a system oscillates under the action of disturbance. A system will vibrate at one or more of its natural frequencies as determined by its mass and stiffness distribution.

Friction, viscous damping and mass acting as a vibrational sink influence the decay and amplitude of vibration. Damping has very little effect on eigen frequency of a system but is of some importance in limiting the amplitude of resonance.

These resonances are influenced by the different boundary conditions of a tonearm.

Our concerns are complicated if a tonearm is viewed as a semi-fixed beam with a "lumped" mass (cartridge) at the end. Boundary (reflected) resonances are observed at edges, shoulders and at the junctions of differing materials. Boundary resonances have been measured at levels greater than the original disturbance.

We are now confronted by Young's modulus, the Eigen frequency of the system, the mass of the tonearm and the interaction of boundary resonances, all of which are capable of interacting and consequently generating additional resonances.

Voltaire wrote "Best is the enemy of better". As observed in the past, not all roads lead to Rome but many will. Neither is there a single avenue to the great city.

It would seem the first choice is that of tonearm, the remainder is a matter of tweaking for best outcome.

As Henry said, much more directly, "I simply use my ears and listen to actual examples BEFORE I blindly theorize."

Peace,

Timeltel, Who can disagree that the first choice is the tonearm? I certainly don't. But I think the controversy surrounds the question of how best to mount a given tonearm in relation to the tt proper, assuming a priori that the choice of tonearm was suitable. And I think we're talking about a pivoted tonearm, not an SLT. Should the tonearm at its pivot be firmly mechanically joined to the tt bearing/platter, or should it be mounted outboard on a separate "pod" for optimal results?

So, has Henry actually listened to a version of either of his tt's wherein the very same cartridge/tonearm combos are mounted to satisfy the "firm mechanical connection" group of us? I really don't think he's done that. And even if he did, must we accept his subjective opinion as gospel? Like you, however, I agree that whatever floats your boat is just fine, for all of us.

Halcro, Timeltel et al

I have a hypothesis that surely explains that my friend Richardkrebs may well be correct. The hypothesis is that Halcro has inadvertently fabricated the worlds first Smartpod, that self corrects any stylus drag by moving in and out relative to the record to null any speed variation due to stylus drag.

Further to the above

02-10-15: Richardkrebs
I do not understand how the time line test proves that the pod is not moving? All it is measuring is the platter's speed.

A basic understanding of the physics involved would help.
Halcro's TT is a direct drive Victor 101. This turntable employs active speed correction using servos. The error correction detection can only measure the difference in relative speed between the base and the platter - those who have studied engineering, physics and mathematics at university would recognise that this a closed system.

The POD exists outside the closed system, and as such if the POD is moving, the servo correction cannot be correcting for this outside force as it is not in the measurement loop.

Therefore if the POD is moving, theoretically, it would reveal itself in the timeline test.