Amperage needs to be a minimum of whatever the stated current draw for the unit is -if that’s not listed then the safest option is to use whatever the rating for the power supply is i.e. KA-350 can supply a 1.7A current draw.
Higher amperage is ok but the voltage needs to match.
You’ll also need to check the tip ring sleeve configuration.
Also, congratulations on the new additions!
EDIT: Looks like the AR uses a 12v supply - best not be using it…