Amp/Preamps to go with Snell B Minors?

I've listened to my Snell B Minors with multiple amps. Adcom 545, B&K 3220, Classe CAV-75, McCormack DNA-2 Deluxe, and Ayre V-5x. I've also used multiple types of preamps. Higher end preamps have almost always seemed to provide improvements, but not the amps.

The bass still sounds bloated and as a salesman recently stated, "tubby". The Ayre was actually one of the worst sounding (maybe exposing too much design weakness?), the McCormack the best with the Classe a close second.

The bass goes low enough, it just has no authority and seems real "loosey-goosey". Anyone recommend something to help wrestle the side-firing 12" woofers?
Although the B Minors are not as generous in the bass as the original Bs, they still would have to be classified as putting out a lot of bass. If you can try a Krell (and we're talking KSA or FPB model, not the KAV line) with your speakers before buying one, it would be worth it, because if a Krell can't tame the bass I doubt any amplifier will. However, don't rule out the possibility of room interactions causing or exascerbating your problems as well, as any speaker with the extended bass response of the Snells will excite a lot of room nodes. You may want to play a bit with speaker placement, if you haven't already, or you could be a candidate for Rives and his PARC system, or a Sigtech or TACT equalizer. Good luck!
if you stand in the corner behind the speakers is the bass sounding heavy and excessive? If so you have a bass standing wave problem in your room which needs some treatment to eliminate it.