Mid-Shift on the Eden WTDI
 

So I am running my Ibanez SR 506 through an Eden ETDI to my Hartke LH1000 head. I play in a hardcore/death metal band and I personally prefer a slightly 'clicky' bass sound. I now have the PERFECT bass tone except for the fact that when I pop certain high notes, I get a peculiar 'duality' of the note - as if there is another note being played. I have come to find that this can only be solved by turning off the mid-shift on my preamp, but this really does take away from the sound I am trying to achieve. What is the best way to get rid of this 'duality' while maintaining this perfect low-end tone?