I have an older 4 knob fretless Carvin w/ Bart J pups. Since installing the Bart pups, that scratch sound from fingers sliding over the strings has increased when changing hand positions. The strings are roundwound set 7/32" from the pups. That`s about as far as I can get them without raising the action. I greatly prefer the roundwound sound so going with flats isn`t really a good solution for me. I also like the action where it is. Are the strings too close the pups? Could a different preamp help, if so which? I`m thinking a NTBT 2 band or NTCT 3 band. Any thoughts ?