If you are headed to three arms and possibly even more carts of unknown type consider a double AudioSpecials Phonolab. (Caveat: I have a bias as I sell this product, so will refrain from subjective comment)
The Phonolab is a twin phono preamp (two preamps configurable for either MC or MM, and can be changed later due to modular card system). Gain and load adjustable. rca + balanced inputs and rca + balanced outputs. The power supply for the Phonolab can power a second Phonolab, giving you 4 inputs and the price for the second Phonolab is less as it's ordered sans ps...
This avoids switching at the input which is preferable.
Best in your search.
The Phonolab is a twin phono preamp (two preamps configurable for either MC or MM, and can be changed later due to modular card system). Gain and load adjustable. rca + balanced inputs and rca + balanced outputs. The power supply for the Phonolab can power a second Phonolab, giving you 4 inputs and the price for the second Phonolab is less as it's ordered sans ps...
This avoids switching at the input which is preferable.
Best in your search.