What happens when?

You'll need to turn the volume on your preamp all the way up, and then go sit right in front of your speakers wearing a hearing aid . . . . . . .

Your Evo 3 is a high output moving coil cartridge and it's basically designed to work with moving magnet phonostages that are built into a lot of good preamps like the C41. It won't be weak, it'll be just right.

If you do get the C41 and your phono sounds good (loud enough with the preamp's volume control around 12 o'clock) you might still find the sound a little hard or glarey, with insufficient bass. If you do, it means the default 47Kohm input load of the Mac's phono section is too high for the EVO and needs to be reduced by adding parallel resistors to the phonostage inputs. A good rule of thumb for the right value resistor (first try anyway) is 25 times the coil resistance of the cartridge. I tried to find the spec for your cart on www.cartridgedb.com but they don't show it. Maybe it's on the spec sheet that came with your cartridge.