@yyzsantabarbara I'm following your AHB2 experience with great interest as I'm considering trialing this amp in my own system, which includes CS 3.5s and a Benchmark DAC2 HGC.
I've read comments about the lean bass of the AHB2, so I wasn't surprised to read of your similar thoughts.
I also, however, note that you consider the amp to be a keeper, so one imagines it has some other very redeeming features.
Appreciate you've just purchased the 3.7s, but I wonder if you've thought about adding musical dual subs to your system?
With a bit of careful setup, this would unquestionably address any perceived bass deficiencies and enable you to enjoy the plus points of the AHB2.
A couple of years ago, I stopped using the 3.5 bass equalizer and invested in a couple of decent dual subs. I've never looked back.
Anyway just a thought for you to consider.
Do keep us posted.