The transition temperature Tc of strong-coupling superconducting alloys AcB1-c is determined with emphasis to tight-binding. Local random Eliashberg-type equations are configuration averaged by means of an effective mass operator on the basis of the CPA. Contrary to the McMillan form the resulting Tc formula involves two different phonon-mediated coupling parameters. The electron-phonon mass enhancement is originated from a complex renormalization factor.