I really dont think its possible to change that unlesss you DO change the preamp. I went through several until I found one that gave me what I was looking for ( great low end, excellent tone, great dynamics, and emotion and beauty) this was no easy task. It took a couple years and several hundred dollars to audition the 5 pre amps I choose from. (McIntosh, Prima Luna, BAT, Modwright, Manley Labs.
Matt M
Matt M