I felt the same about mine. I didn't like the strings at all. There's an upper midrange that just grates and can't tame it well enough to my satisfaction. Best I can do is turn the treble down a tiny bit, and bass up a tiny bit. That seems to scoop out some of those mids... but if you overdo it, it ends up removing too much and getting too boomy.
Good news is... the strings lose that annoying zing very quickly (at least in my hands, I did play it a lot). But different strings would be a good move.
I bought a Schecter Model T two years ago, and when I got it I had some of the same annoying mids I got on the Sandberg. The Model T is equipped with EMG pickups and 2EQ preamp and the EMG EQ was just no good to adjust that (I am not a fan of 2 band preamps, but the Sandberg one is quite decent). I put a set of DR Sunbeams and... what a different animal it became. Lovely.
I have a set of Sunbeams for the Sandberg, but I haven't repaced the strings yet as I've found a sound I really like for my new funk band and I'm scared to lose it

I know, I know, but I'm a bit silly like that with string changes... I never like any new string at first, so I wait until I can't wait any longer