A connection system for a quantum computer that employs constant impedance connectors with attenuation or filtering components or both embedded therein or within an adaptor removably insertable within an adaptor housing for use in a cryogenically cooled quantum computer. The connection system provides a higher density of cables traversing through a hermetic sealed top plate, and which are accessible to chill blocks to reduce the thermal energy from the signal lines. Attenuators or filter circuits are embedded in the constant impedance connector housings, or provided in adaptors that connect on each end to form mating constant impedance connections, in order to reduce signal strength as the signal progresses through the cryogenic environment and to remove extraneous electrical signal noise.