There are outboard 'input selector' boxes you can use by just connecting their output to one of the source selections on you integrated. These a passive line level devices with out a volume control which is what you want. If you get a seperate preamp you either take the signal out of the preamp line out which has the volume control or thru its tape out. If you do the former you potentially degrade the performace of you systems by having two volume controls in the loop. If you do the latter, your spending a lot of money for a switch box.
Now, if your integrated has provision for the seperation of the pre-amp section from the amp section you could just connect a new preamp directly to the amp stage, however I'm under the impression that the DK doesn't have such a provision.
Anyway, the switch box is an excellent and cheap solution to your problem especially if you're only going to use it for 'lo/mid fi'.
You might do a little reasearch on these units if it interests you.
Now, if your integrated has provision for the seperation of the pre-amp section from the amp section you could just connect a new preamp directly to the amp stage, however I'm under the impression that the DK doesn't have such a provision.
Anyway, the switch box is an excellent and cheap solution to your problem especially if you're only going to use it for 'lo/mid fi'.
You might do a little reasearch on these units if it interests you.