princeton non `verb , mods ??`s

[racehorse]

I asked a few questions on this amp awhile back.

after adding a bias pot . putting new tubes in .

jan phillips 6v6`s , EI ecc83 PI , RCA 12ax7a first tube

I started with a 5v4 recto , this all sounded good . I recently put a nos 5ar4 in , tighter bass , plate voltage stays a little higher.

I biased it to 10.5 w , plate dissepation , sounded best
with the 5v4 ,410v@ 26ma
with the 5ar4 , 420v@ 25ma , 10.5 w

I was trying to kept the plate voltage up and this seemed to be the break even point , I f I biased it hotter the plate voltege dropped off quickly .

Now the questions

Is the small power transformer , loading down , so I can`t keep the plate voltage up and run the tubes hotter?

is it caps?

the 10.5 watts dissipation was the beak point .

the stokes mod , raising the plate voltage on the PI
what differance in sound is this going to make?
more headroom ?tighter low end?more output ?

6v6gt`s vs. 6v6g , sound different?

brimar 6v6s , oppinions?

thanks
racehorse