I just replaced my Carvin preamp with an Audere Pro Z, and "WOW!" was my first reaction. The Carvin pickups (J99 neck, HB 5 Mm copy in bridge) actually sound great! Besides being a bassist I am a recording and live sound engineer and a bit of a tone snob. I love the way the Carvin plays, not a dead spot anywhere, every note jumps right out, but I never really liked the tone too much, adequate but kind of dull. I guess the Carvin preamp really colored the sound in a bad way. It's like some ugly overtones were removed, and the top and bottom are very present in a clean way. I realize that this my descriptions are very subjective and not scientific, but hopefully this can help someone sitting on the fence on this issue. Getting the Carvin preamp out was a little tricky but installing the Audere was very simple (though in my case I had to swap the wires to the input jack, the Audere wouldn't fit) with clear directions. Also I had to make two of the holes slightly larger, no biggie. This preamp gives you a huge amount of tonal adjustment possibilities, but I'm just using it in default mode with a tiny bit of bass and treble boost and loving it. Oh, my unit has volume, balance, bass, treble, hi mid, lo mid.