Tell me more about your setup: what bass and amp are you using? Also what settings on the EP Booster? Is it adding any gain or just the EP booster's "sweetness?"
Well, I'm actually not running that setup anymore, but I can reconstruct mentally
Bass is one of:
-P with a T-bird pickup added in the bridge position and a Quarter Pounder as the P pickup, and a Tonestyler replacing the normal tone pot
-G&L L2K, using neck pickup
Amp is a Markbass 12" combo, set with the low mids notched out a bit, and with the VLE (vintage loudspeaker emulator) set about 8:30 to smooth out the top. I don't care for the pre-amp that much, so I went directly into the effects return.
Typically ran the EP Booster at about 11:00 or so, so there was some added gain, though I also needed the hotter signal since I was going into the effects return. I had the internal treble boost set to off.