On Sun, 12 Oct 2003 08:52:53 +0100, Jim Lesurf
wrote:

In article , Kurt Hamster
wrote:


I was always under the impression that nickel placket plugs worked best
with nickel plated sockets, and gold with gold etc. Is that incorrect?

I think you are correct. Using dissimilar metals may in some cases mean
some sort of electrochemical action may occur. How much this matters in
practice, I have no idea, though. I tend to use gold on gold as it seems to
resist tarnish and being a soft metal can be expected to provide a good
contact area. However for all I know, some other choice might be just as
good or better. I've also used a variety of non-gold plugs and sockets over
the years, and most of the time they don't seem to have given me problems.
Main exception being some old loudspeaker DIN plugs/sockets which used to
tarnish or even 'burn' with time.

FWIW I prefer the 'high quality gold plated' Maplin plugs as much for the
way they can be fitted to cables as for the gold coating. My experience
with the cheaper phono plugs is that they fail more often due to a broken
solder joint or wire at the plug than due to tarnish as they don't give
much support to the wire. I also find them fiddly to assemble and
unsuitable for large diameter coax.

Slainte,

Jim

In the case of the DIN loudspeaker connector, it is simply an
ill-conceived idea - totally unfit for its purpose. Contact area is
minute, and with very low spring force.

For coax connectors, they generally work in an impedance environment
(high load R) where they would have to be virtually open circuit
before they manifested any symptoms of poor connection.

Having worked on the design of a 40GHz edgeline switched attenuator
that relied on virtually force-free contacts that barely wiped, I can
say with some authority that the ultimate in reliability comes from
soft gold contacting hard gold.

d

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