  We study the charge transport properties of fields confined to a
(2+1)-dimensional defect coupled to (3+1)-dimensional super-Yang-Mills at
large-$\nc$ and strong coupling, using AdS/CFT techniques applied to linear
response theory. The dual system is described by $\nf$ probe D5- or D7-branes
in the gravitational background of $\nc$ black D3-branes. Surprisingly, the
transport properties of both defect CFT's are essentially identical -- even
though the D7-brane construction breaks all supersymmetries. We find that the
system possesses a conduction threshold given by the wave-number of the
perturbation and that the charge transport arises from a quasiparticle spectrum
which is consistent with an intuitive picture where the defect acquires a
finite width. We also examine finite-$\lambda$ modifications arising from
higher derivative interactions in the probe brane action.
