Tube amps with BALLS in the low end registrer ???

Esoteric and exotic? I don't about that, I'm not sure I even really know what you mean by that. If you want a great (one of the finest) tube amps with SS-type bass and control get the CAT. The monos are $30,000, that should be pretty esoteric and exotic - I think. On the other hand, there is a $300,000 WAVAC....

You did mention hybrid, I think Tenor has new hybrid amp on the market.

yes Tenor a lot of dineros.......

I have a CAT Ultimate preamp and it has great bass. If its an indicator of their amps, you may want to look at CAT. I also have a pair of Joule Stargates which, although they do not have slam and I don't expect them to in my setup, they do have the best bass timbre perhaps of any amp I have heard. By timbre, I don't mean boom, but I mean the underlying detail and tone and harmonics. Jeff

if you want exotic and esoteric, commission josh at electronluv.com to build you a custom masterpiece. i'm sure he can make you a fabulous piece of gear, though i don't think he dabbles in amps over 25 watts.