On 2006-09-28, Jim Lesurf wrote:
In article , John Phillips
wrote:
I have tried out squash balls cut in half under certain bits of kit [1].

In a previous career in semiconductor devices, the group I worked in
used to mount vibration-sensitive kit on solid slabs which were
suspended on compliant air-filled rubber "springs". This certainly
worked.

[1] I couldn't hear any difference with the half-squash-balls under
anything I had (but I don't use my Thorens/SME/AKG these days so I
didn't try that).

I have found a half squash ball works well when I squeezed one in between
the top of my DVD recorder and the shelf above it. This dampens down the
vibrations and means I can't now hear the rattling of the tinny lid as the
disc is whirled around.

Above said, I did also take of the lid and fit 'dedsheet' (from Wilmslow
Audio) inside the case and this also reduces the rattles and transformer
buzz.

Interesting. I might try that with a PC I have, to quieten it down a
bit more.

[2] Optical lithography kit which aligned wafer and mask to sub-micron
precision.

Half inflated bicyle tyres in between two flat plates of wood come to mind
here... :-)

The air-filled rubber springs we used were a little like short shock
absorbers and did have bicycle-tyre-style valves to allow them to be
pumped up to the right pressure. I am sure bicycle tyres would have
been less costly. IIRC we actually connected them permanently to a
regulated air line to keep the pressure correct.

The slabs we used were made of a medium-weight composite material of
some kind which sounded rather "dead" when rapped. I assume that was
part of the anti-vibration design.

--
John Phillips