I've been using an ART tubechannel microphone preamp as a bass preamp in my rig for a while now. I recently plugged a gibson 335 into it, followed by a fender strat. The tones coming through weren't bright and crisp, regardless of EQ. They made a woo woo muffled kinda tone like when you hear someone blasting music from a closed room. We then plugged my guitar buddy's guitar head into my cabs and it made a normal crispy tone. What would be making the tone of my bass/guitars sound so....woo woo? Is it the preamp circuitry? Perhaps the 12ax7a's need to be swapped out? Or should i just give in and use a bonified bass preamp?