In article , Serge Auckland
wrote:


As an aside, does anybody have any experience of stylus lifetimes. Van
Den Hul claim 3000 hours for theirs and I was wondering whether that
applied to the VdH brand or to the VdH profile.( Who makes VdH profile
styli?) Also, what about the V15 Micro-Ridge. Shure claim 800 hours,
which seems very low.

I doubt it can be claimed for the profile. The total effective tip mass
of the assembly, and the compliance, etc, of the system will dictate
the playing force required, and the forces between the stylus and
the groove walls. Hence the same stylus in two different designs
would return different rates of wear.

The problem, I suspect, is that this varies a lot with conditions of use,
etc. However the comments I got from Expert Stylus were that low playing
force/high tracking designs like the Shure V15/III could work well for very
long times if used with care on clean LPs.

I don't know how much playing time I have racked up with my MR stylus, nor
with the previous HEs, but for one HE they said another 300+ hours of
similar use would probably be fine!

My understanding is that the VdH, Micro-Ridge and similar profiles have
to use grain-orientated diamonds which makes for a much longer life
than spherical or standard elliptical profiles which don't need
grain-orientated diamonds. Is this true or just marketing hype? As Jim
said, there's a real shortage of proper information on vinyl replay
these days.

A further problem is that the shapes with narrow contact lengths may wear
more swiftly - in the sense of the profile changing quite quickly. Might
only be MR or VdH for the first 20 hours... 8-

I recall a story from BR engineering who used to have a problem with wheel
wear and 'hunting'. (Train weaving from side to side.) They used to
frequenctly re-profile the wheel tyres to a cone section. Then they found
that if you left them alone, the wear produced a shape that minimised
hunting. :-)

In a similar way, I have my doubts that the Shure styli I have still
maintain their original shapes (which were probably more like flatted-off
parabolic cones anyway to get the 'ridge' radii[1]) but that may still mean
they play safely and with low distortion, etc, if the forces are low and
the shape is able to reach into the corners of modulation. In reality, the
contact area isn't likely to just be the 'infinitely hard LP wall'
geometric one.

Would be interesting (but tedious) to do an experiment on distortion, etc,
as a function of how many hours of playing time have been clocked up. I can
recall Stan Kelly and others doing work on wear of spherical shapes, but I
can't recall seeing anyone do it for the fancy shapes people sell these
days.

FWIW I have become rather sceptical of claims that imply that the results
depend on the stylus profile whilst ignoring various other factors. I
had my doubts about this, and they seemed confirmed by the measurements
I did recently...

Slainte,

Jim

[1] Hooray! A plural with an 'ii' ending. ;-)

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