Small or big tubes/valves for pre amp ?

Given the number of circuit designers, over the decades, that have chosen to utilize both nine pins(ie: 6DJ8 iterations) and octals(ie: 6SN7s), and the excellent results, that have been attained with both choices, has led me to believe that blanket statements are worthless. They only serve to prevent some from experimenting on their own, to find their personal preferences. Regarding Sylvanias and, "having Bass": I don’t want my tubes to, "have" anything of their own, but- to pass what’s presented them, without leaving their own footprints. The author of the 6SN7 comparison, made this statement(his first sentence): "Let me stress that the optimum tube for your system will depend on your equipment and how your ears judge the tube’s ability to reproduce live music." It seems some miss(or choose to ignore) those very salient(and universal) points(circuit variations/subjectivity).

@mulveling-  Mixing tube types in a circuit, to reinforce the positives of each, doesn’t ONLY apply to 6SN7s, but works in most any application.

Best preamp I have ever heard uses the 6N1P

@rodman99999
My statement should have been that the Sylvania 6SN7 do no re-produce bass very well. They are fantastic at almost Everything else
I think you understood what I meant. Take techno music for example . Most of it has a lot a Bass. I also understand that a lot of tube amps are not heavy hitters in the Bass dept.
Some people may not notice it too much... ????
But below is the real problem with 6SN7s  IMO as well as Many other's opinions too 

The only one I really liked sonically was Tung-Sol black glass round plate VT-231, but they’re so hard to source with any decent life left - and again, good luck with noise

This worries me a bit to hear, although I am no bass freak, I like tight bass, using a solid state power amp instead of tube power amp make any difference?