take the cover off the pre-amp, look at all the out-put tubes only, if they have coupling caps, one to two next to the out-put tubes, you will be fine, these coupling caps are designed just for DC out-put, as a matter of fact, if your pre-amp has the coupling caps on the out-put tubes, you will have no dc reading what so ever, then you can use your Krell with no issues, it is impossible for Dc to pass with DC coupling caps on the out-put tubes, how do I know?, I use a tube/solid state hybred cd-player directly to my krell 700cx amp, my player has two DC coupling caps on each out-put tube, blows the doors of most pre-amps performance running direct like this!