I've been recording with the 388 for about a year, and lately without the dbx.  What an amazing improvement!  I SAY FORGET THE DBX!!  without it you can push the levels quite hard and get some nice compression, and the playback is MUCH more realistic--clear and with no pumping or swelling or wet blanket effect.     also, I think it's important to not let tape hiss become some sort of horrible bogeyman--it's OK to have a little hiss--IT'S TAPE, AND WE LOVE TAPE!!   And the feeling of simply getting back what you put in is much more honest.  try it.  hit the tape hard you'll be happy.