I own and use the Krell 400xi in one of my three major systems. I have done quite a bit of testing the RCA inputs VS. the Balanced inputs using my transport & Dac; and TT; using the same brand interconnects (RCA vs. Balanced). As you already mentioned there is an obvious increase in db however I have used my sound level meter to assure I'm listing to the same music at the same level. My conclusion is I cannot hear any improvement in dynamics using 1/M or 1.5/M interconnects. I would imagine if we were talking really long runs the Balanced would be an improvement.