Small or big tubes/valves for pre amp ?

I use 6SN7GTBs in both my Schiit Freya (4) and my Dennis Had Firebottle SEP HO (1). NOS Amperex in the Had, NOS RCAs and Sylvania "chrome domes" in the Freya...utterly great sounding all around and I haven’t noticed any lack of bass with Sylvanias as this combo has slam for days. I do have a pair of REL subs in this system though...in the Freya The RCAs are in the "input" and the Sylvanias are the others, but it sounded great with all Sylvanias, just a little better with the RCAs. No dreaded microphonics, no hum, certainly the quietest tube rig I’ve heard, and, again, not a euphonic grease fest but clarity and tonal bliss (I think I just went too far)...efficient speakers make it work. All 6SN7GTBs certainly simplifies things for tube collection fun, and GL KT77s (2) round out the tubulars in this system.

I actually use the Shuguang Black Treasure KT88-Z in my Granite 864-SR. I also have  a pair of the Sylvania 6SN7GTA Chrome dome 3 hole black plates and 2  pair of Jan CHS (sylvania) 6SN7GT-VT231..
If i try to use the SylavniaGTA  in V1 and Sylvania GT in V2  or any combination of these in V1 or V2 .. I lack BASS.
I had originally ask for and tried the Ken Rad 6SN7 with the Sylvanias V1,V2... kiler bass , but Ken Rads were Microphonic. I then tried some Tung Sol Round black plates . They were also microphonic. I asked Andy to send me another pair of Sylvanias that have good bass... to use with the other Sylvanias , his reply was that none of the Sylvanias can do Bass as well as the Ken Rad or the Tung Sol, (cause once i heard the bass with the Ken Rads and or Tung Sols .. i had to have it)  Andy actually said that the only 6SN7 tubes that can do Bass like I heard and wanted was the Ken Rad or the Tung Sol  

So if using two Sylvania 6SN7, one in V1 and the other in V2, and it did not matter which Sylvanias (i tried. I tried all but the Metal Base ones) the Bass was lacking .
As a matter of fact most of the combinations of 6SN7s in V1 and V2 in those amps, lacked Bass IMO. ...unless i had a Ken Rad or Tung sol in V1   That was my experience with 6SN7 tubes.
Therefore i know use a 6F8G in V1 with the 6SN7 adapter.
https://www.ebay.com/itm/Tube-adapter-6F8G-to-6SN7-1-pair-/153299100833?item=153299100833&ViewItem=&nma=true&si=apYGBdYiWyN493VkmTacst7L9wQ%253D&orig_cvip=true&nordt=true&rt=nc&_trksid=p2047675.l2557

.

Just glad I stocked up on all my favorite 6SN7s and early 60’s, grey plate/shield, Siemens CCa’s(the CDP takes six), before they became unobtainium!  Again: Happy listening!