How to calculate the Step-up gain for MC cartridges.
The gain of a step-up is specified in dBs. When you multiply the gain of the step-up with the output voltage of your element, you have the gain at the Phono amplifier. For most elements up to 0.35 mVolt output voltage you need a step-up ratio of 1:20 (27 dB). Above 0.35 mVolt a step-up ratio of 1:10 (20 dB) is recommended.