Stepups and MC cartridges. Posted March 20th, 2006. The secrets of a successful marriage. Seb. Part 1 head amplifier of MC section on a phono section. passive (Sony HAT110, Ortofon T5) to 296 ohms (FR XG5) for the Briston TF1, 40 ohms is the minimum of the range: the natural impedance (and then the load impedance) is much to