I have a Fender mex jazz 5 string bass that I upgraded the pick ups to the Seymour Duncan quarter pounders. Looking at adding an onboard preamp because I also play a USA Fender Deluxe Pbass and when switching basses, my volume levels are constantly changing. Love to boost the jazz to cut down in the headaches. Any recommendations? Not sure how the tone will change. I play from black gospel to country to jazz.