So ive used my sony ECM-957 with good results in the past. I recently got my CA preamp in the mail. Is it a good idea to use the pre with the already battery powered mic? it seems like the recordings from the ECM were a little quiet so maybe the amp would help with that? Also, should I use the HPF setting? Not sure exactly what that is. Any suggestions are appreciated. BTW, the show is P Groove in Roanoke, VA tonight.