On Thu, 10 Sep 2009 20:45:07 +0100, Malcolm Lee
wrote:

On 2009-09-10, Eiron wrote:
UnsteadyKen wrote:
Don Pearce said...

Hold an LP up balanced on two fingers at opposite edges - you will see
how much it sags quite easily. Obviously it doesn't sag as much as
that with six suspension points, but it sags much more than enough to
generate a huge signal.

The Hydraulic was designed for the thick'n sturdy pre 73 oil crisis
discs which are a totally different animal to the later floppies.

I got a couple of lp's last week, a Decca ffrr from 1965 and a bog
standard EMI Columbia from 1966 and neither droops on your finger tip
test, on the contrary significant pressure has to be applied to deform
them.

I just rested an LP on two points. The centre drooped by 4mm.
Of course UnsteadyKen didn't measure anything....


I've just rested my LP ("With The Beatles" Mono PMC 1206 pressed
in 1964) on two points. The centre drooped by maybe 0.2mm.

Of course Eiron generalises from his limited personal experience
to the universal...

You have both presented a single figure. But apparently you are
allowed to generalise, but Eiron isn't How does that work, exactly?

d
--
Pearce Consulting
http://www.pearce.uk.com