Thinking out loud about 12au7 solo boost

[Tone Junkie]

Ok so Ive been rolling this TOS. 2 clean channel build around and around  in my head. Im going with a tube driven effects loop so I have 1 side of 12a_7 sitting idle so I thought of using it for a solo boost I could make it 12dw7 and have a 12au7 free or a 12ax7 and one of those free I dont know if I want to boost in front of effects loop or after before the PI.
 Im using a 12AT7 for the PI so it should have lots of head room. Just havnt quite seen anything in my studies of people doing it after a loop. Whats your thoughts my wise and trusty friends.
Thanks Bill

[jjasilli]

Not enough info.  What amp? What effects loop?  Maybe post schematic.  Meanwhile 12ax7 has gain of 100; 12au7 - 17.  Maybe too little gain for a boost stage.  OTOH 12au7 is a good driver tube.  So, it's a candidiate for a cathode driven effects loop, eg.