On Tue, 29 Sep 2009 06:34:40 +1000, "Trevor Wilson"
wrote:


"Arny Krueger" wrote in message
...
"Trevor Wilson" wrote in
message


As a general rule,
MM carts are far more 'forgiving' of tone arm bearings
and resonance issues than MCs.

Why would this be? More damping?

**Damping and arm (bearing, headshell, etc) rigidity. SME bearings (kife
edge) are spectacularly unsuited for use with MC carts. Later SME arms
addressed the problems (only partially successfully) by using a damping
trough. It was a kludge. Arms like the fabulous Rega RB300 showed how a
relatively low priced arm could be built to deal with MC carts.

The damping should all be associated with the spring - which is the
stylus cantilever suspension. There should be no expectation of extra
damping associated with the arm bearing, which is ideally as free to
move as possible. Indeed damping of the arm bearing impedes arm
movement that is needed to prevent low frequency high-amplitude stylus
excursions.

In other words, what is being damped is the spring - mass system of
the cantilever and effective arm mass. The right thing to damp is the
spring involved in that resonant system. Ie, the damping must be in
the cartridge.

d