  We present a spectral investigation of X-ray binaries in NGC 5128 (Cen A),
using six 100 ks Chandra observations taken over two months in 2007. We divide
our sample into thermally and non-thermally dominated states based on the
behavior of the fitted absorption column, and present the spectral parameters
of sources with L >2x10^37 erg/s. The majority of sources are consistent with
being neutron star low mass X-ray binaries (NS LMXBs) and we identify three
transient black hole (BH) LMXB candidates coincident with the dust lane, which
is the remnant of a small late-type galaxy. Our results also provide tentative
support for the apparent `gap' in the mass distribution of compact objects
between ~2-5 Msol.
  We propose that BH LMXBs are preferentially found in the dust lane, and
suggest this is because of the younger stellar population. The majority
(~70-80%) of potential Roche-lobe filling donors in the Cen A halo are >12 Gyr
old, while BH LMXBs require donors >1 Msol to produce the observed peak
luminosities. This requirement for more massive donors may also explain recent
results that claim a steepening of the X-ray luminosity function with age at Lx
>= 5x10^38 erg/s for the XB population of early-type galaxies; for older
stellar populations, there are fewer stars >1 Msol, which are required to form
the more luminous sources.
