Turntable "suspended in a vacuum" to prevent vibrations?

[muzician21]

On this page

http://www.bornrich.org/entry/top-10-most-expensive-turntables/

Look at number 5 - the description of the Continuum Caliburn includes
this phrase:

"The turntable employs a magnetically levitated magnesium platter,
which is suspended in a vacuum to guarantee there are no vibrations."

Suspending in a vacuum sounds like a contradiction in terms. A vacuum
tends to draw things in. At some point the turntable has to be riding
on some kind of bearing - i.e. something solid has to be contacting
something solid - which AFAIK provides a potential conduit for
vibration transmission. From a theoretical standpoint, how would you
"suspend" something like this in a vacuum in a way that guarantees no
vibration?

And of course a vacuum requires a seal, which sounds like something
with the potential to fail.

[William Sommerwerck]

Suspending something in a vacuum does not, in and of itself "prevent
vibrations". Whoever wrote this promotional material has little practical
understanding of physics.

[Michael R. Kesti[_3_]]

William Sommerwerck wrote:

>Suspending something in a vacuum does not, in and of itself "prevent
>vibrations". Whoever wrote this promotional material has little practical
>understanding of physics.

I worked for about a year for a company that makes chambers, valves, and
pumps for the high vacuum industry and was amazed at the misconceptions
of many within the company concerning high vacuum. The best was the
assembly technician who confused vacuum and gravity and believed that
astronauts floated around as they do because they were in the vacuum of
space!

--
================================================== ======================
Michael Kesti | "And like, one and one don't make
| two, one and one make one."
mrkesti at hotmail dot com | - The Who, Bargain

[UnsteadyKen[_3_]]

William Sommerwerck wrote...

> Suspending something in a vacuum does not, in and of itself "prevent
> vibrations". Whoever wrote this promotional material has little practical
> understanding of physics.

It's the fault of whichever eedjit wrote the article for bornrich. He
appears to have confused the bearing design with the vacuum platter
clamping system.

Continuum themselves say...

"Other features include the use of a ball/thrust pad configuration for
vertical motion, and bronze alloy for the axial motion.

The bronze alloy contains higher than normal tin compounds, which fill
any micro asperities in the shaft over time to create an ultra silent
bearing.

We chose not to use magnetic vertical bearings as the VTA is constantly
changing due to the rotational effects of the platter, which results in
a loss of depth and soundstage."


The whole things rubbish, VPI will no doubt be surprised to learn that
they are now a subdivision of the Teac corp and that their HRX table
features 24 extremely, 300rpm AC synchronous motors, Or perhaps not.

I'm off to read the in depth reviews at
http://www.bornrich.org/entry/top-10-luxury-speakers-everyone-cant-
afford/

--
Ken
http://www.members.lycos.co.uk/buddyduck/