I am using an Edirol usb external interface, i go from that into a small tabletop EQ, then to my peavey FX16 board. My tabletop EQ has a tube preamp. It takes my signal out of the nasty digital realm. Makes it so warm you could hug it...lol This combination kicks serious serious booty ......
P.S. i split the signal out of the tube preamp, and run it to my rack mount Furman Punch10 bass process. Sounds much nicer, and smoother then a ordinary crossover.