[Mesorah] am vs. am

[Michael Hamm]

R'MP wrote: << http://sites.google.com/site/torahreading/mafsiqim >>

According to this, the tip'cha is a second-level mafsik and r'vii is a
third-level.  In Y'sha'ya 30:5, "am" appears with a patach and a
tip'cha (in Mechon Mamre's online version; I haven't checked any other
versions).  In Ester 3:8, it appears with a kamatz and a r'vii (with
the same caveat about versions).  So it's not the trop that determines
the vowel (unless there's something weird going on, where a m'shares
gets a patach, a lower-level mafsik gets a kamatz, a higher-level
mafsik gets a patach again, and a sof-pasuk gets a kamatz again.  (And
I haven't checked Tanach thoroughly to see whether even that is
possible)).

So if it's not the trop, what determines "am" versus "am"?

Kol tuv,

Michael Hamm