Common-mode choke inductors are useful tools for resolving grounding issues in large detector systems. Using inductive components on cryogenic pre-amplifier boards has so far been prevented by the poor low-temperature performance of common ferrite materials such as NiZn and MnZn. Recently developed nanocrystalline and amorphous ferrite materials promise improved performance up to the point where using magnetics at liquid nitrogen temperatures becomes feasible. This research applies the work of Yin et al. on characterizing ferrite materials by constructing and testing a common mode choke inductor for use on detector pre-amplifiers for the ELT first generation instruments.