I have a TRB6II by Yamaha, and a while back the on board preamp died, I went to a Yamaha dealer and was told that a new preamp would cost about $270 plus about $125 labor, well I never fixed being that I have another 10 basses, and I saw some TRB going on ebay for a litle over $500. Well my question is, does anybody have any experience with that model, or would know of any compatible type of preamp, with 5 knobs, Volume, balance, treble, mid, and bass, Thank you.