Let me reply to the entire "Midrange" discussion. The area where my treble and bass bands do not overlap is around 400-500 Hz. As you boost treble and bass, you are attenuating the mids. So the less boost on both bands, the more midrange is present.
While I have always said less is more on the pre, I continue to get extraordinary compliments from recording engineers and front-of-house sound people that with Sadowsky basses, they do not have to touch a thing on the board. They are virtually "plug and play," and I consider these the best compliments I could receive. After 40+ years, I am also convinced that the attenuated mids contribute to how well the bass sits and the mix, both recorded and live.
This does not mean that more mids might not sound better to the player. Many years ago, Will Lee requested "more punch" from his basses. I tried everything I knew to give him that....woods, pickups, pickup locations, but I could never satisfy him. One day I told him to get a parametric EQ and tell me what frequencies matched the sound he heard in his head. He replied with 500 Hz. So that is exactly the "mid scoop" that my preamp creates.
Now the main reason I never had a mid control was that with a JFET circuit, you cannot change the mids without affecting the bass and treble. So I began prototyping 3 band op-amp preamps. However, with everyone I gave Will to try, he would reply, "It doesn't sound like my bass". The lesson here was that it is impossible to duplicate the sound of my JFET preamp with an op-amp circuit. So back to the drawing board and the way we created the mid boost for the Will Lee preamp was to piggyback a mid circuit on top of my JFET circuit.
Will tells me that he never uses the mid-boost in the studio. He only uses it for live playing.
So my suggestion, if you want more mids, is to adjust this on your amp or get a pedal that will boost the mids. I would hope you would not replace the preamp, as nothing else will sound like a Sadowsky.