Tube Integrated with deep bass

PrimaLuna DiaLogue Two - provides deep articulate bass. If you can get by with 38 rather robust watts per channel, you need look no further.

If it is in your price range the Graaf 50B that is for sale is a very very good tube integrated ....I have no affiliation with the seller but used to own this model and if not for going to much more expensive seperates I would not have found any real improvements. It is also great looking and built well.

Well, my military intelligence tells me that the giant shrimp of integrated tube amps with good bass is the VTL IT85. It's the colossal olive of tube integrateds and you could even pick it seeing blind.

Aronov LS-960I has been a tube integrated bass performance champion in a reasonable used price range, $1200 range.
Although manufacturer no longer active, it has a straightforward design that any tube repair facility can work on.
Not vintage, and sold in the 21st century.
The overall sound is very natural, or realistically musical, not simply killer bass.

Audio Note Soro SE has amazing bass

I am selling mine but it makes no difference on my opinion - awesome bass for tubes or solid state