If your preamp will not allow you to install the resistor, then you have to go with the switch positions they provide.
Personally I prefer to do as much loading with resistors as I can, rather than capacitance. I worry about the capacitor and inductance of the cartridge becoming a tuned circuit...
Personally I prefer to do as much loading with resistors as I can, rather than capacitance. I worry about the capacitor and inductance of the cartridge becoming a tuned circuit...