Vintage DD turntables. Are we living dangerously?

Hi Halcro,

On another thread you indicated that you've transitioned from a metal skeleton metal frame plinth to a solid Granite plinth for your TT-101. From the picture, I didn't see holes in the circular Granite to accomadate hardware for securing the TT-101. Is the TT-101 resting on the Granite without being fasten to the Granite?  Would you please describe what are the sonic differences? Thank you

Norm

Hi Norm,

When I first set up my Victor and armpods, I supported the turntable motor with its own metal shroud on Tiptoes
http://i.imgur.com/Xp97BF8.jpg
This at first sounded better than most tables I had previously heard but I thought I could do better than this makeshift arrangement.
So I designed and had built, a stainless steel cradle
http://i.imgur.com/UuEyECm.jpg
which had adjustable spike supports and three rubber supporting pads on top to rest the motor assembly
http://i.imgur.com/2FH8xGR.jpg
This was indeed an improvement in rigidity over the previous model, however after a few years, I discovered that the lightweight nature of this supporting structure allowed for accidental movement of the geometrical relationships vis-a-vis the massive 24lb armpods.
So I designed a circular ’plinth’ cut from a single solid block of granite and polished
http://i.imgur.com/ouvBGRN.png
I lined the inner surface with cork to absorb the electro-magnetic waves bouncing around from the transformer, power supply and motor unit and had the same three rubber ’button’ supports fixed to the top to support the motor unit itself
http://i.imgur.com/h673918.jpg
The improvement in sound was revelatory and confirmed the fact that Newton’s third law of motion (For every action there is an equal and opposite reaction) applied to the motion of turntables.
The centrifugal force of a spinning platter must be resisted by enough ’mass’ to avoid movement.
http://i.imgur.com/ddKNHVx.jpg
This is more readily seen in a suspended turntable where the centrifugal force is not resisted and must create movement about the sprung suspension.
The Kronos turntable with its two counter rotating platters effectively solves this problem for suspended turntables.
http://media.tas.zeitpress.com/articles/images/JH%2011%20The%20Kronos%20Sparta%20turntable%20comes%2...
With an unsuspended mass-loaded turntable of any kind, that centrifugal force is absorbed and thus resisted by the mass of the supporting structure.
The sonic effects of this added mass to the TT-101 in my situation, is a tightening of the presentation together with a relaxed delineation of the entire soundstage and instrumental focus.
The detailing snaps sharply and the lower registers plunge solidly with an unwavering pitch and tunefulness.
And as a bonus.....the geometrical relationships to the solid bronze armpods remain static 😘

Regards

"With an unsuspended mass-loaded turntable of any kind, that centrifugal force is absorbed and thus resisted by the mass of the supporting structure."  I don't want to say "I told you so", but I did tell you so back when that was a point of contention among us. Back when Raul was recommending just sitting the naked chassis on a set of AT pucks that were said to have magic powers.  And let me apologize in advance for being pedantic, but this is not a "centrifugal" force at all.  This is a force that is described in Newton's Third Law of Motion: "for every action, there is an equal and opposite reaction". Thus it is a force vector that has a direction described by an arc opposite to the direction of the arc of turntable rotation.  This is why and how the Kronos works; the lower platter, of mass equal to the working platter, is rotating opposite to the direction of the working platter. and this effectively cancels the forces. Otherwise, the tail wags the dog.

And finally, to be even more annoying, there is no such thing as a "centrifugal" force.  The force described in that commonly used misnomer is actually centripetal; to keep the object from flying off in a straight line, a force directed toward (not away from or "centrifugal") the center of rotation is generated and required.