I got the Freya mostly to satisfy my curiosity on a passivePassive mode, will give you the most transparency of any preamp.
Just have to make sure your poweramp is the industry standard of 47kohm input impedance or higher, which most are.
And the source should have an output impedance of "less" than 1kohm (1000ohms) which most are.
And with passives, keep the interconnects to the poweramps less than <2mts and good quality low capacitance ones, which most are.
Cheers George