my understanding from memory
1) it does not do RIAA and 2) it will amplify if you select MC
We only want to amplify once, so there are two ways to do hook up for MC.
Select MM and use your own Phono Preamp which will amplify and RIAA.
or
Select MC if it's a MC cart. It will amplify and plug it into the MM input on your Phono Preamp.
make sense ?