My perception is my 100w Ampeg V-4BH (not the 70s style V-4B, which is different), has more lows than the ABM, which I find has tighter lows and is less big sounding if both were set flat. It has the same pre as an SVT, just different power section. The BH might be a little fatter, maybe, but is more clean sounding and that might contribute to that. In fact I use the ABM for basses that are a little hallow or boomy to tighten things up a bit. I love both, and they complement each other well. AN ABM with about 5 pre tubes like an Ampeg 3PRO would be killer.