Pre amp into audio interface

[pko]

I want to plug in a external preamp into my interface but im not sure what tha best way is would you go out of tha pre amp into tha built in pre amp on tha interface and turn that down or go into tha interface line in I tried both but with not much sucess is there something im missing?

[cacaman]

homie, u gotta go from the out of the preamp into the LINE IN of your interface. DO NOT go into the pre on your interface.