The A21 Signature phono board has settings for MM and MC cartridges. It is factory set for MM so if you have an MC cartridge or change to an MC cartridge it will require adjusting. Your retailer will be happy to do this for you but it is something that’s easy to do. The phono board has a set of four ‘jumpers’ that just need moving across to the four spare outer pins. Remember to disconnect your amplifier from the mains supply.