I'm playing live again with a group that mics the drummer, horns, guitars, singers, everything into a nice big EAW PA. I'm using their SWR Super Redhead or Carvin, for stage volume, and lined-out to the board. I don't like the sound of either of these, and want to use my old Portaflex B15N. What do you suggest: hang my trusty SM57 over the top, or install an xlr or something off the preamp? I want to capture as much of the Portaflex tone as possible. Thanks for your experience and advice!