Your amp requires 1.4vrms to reach maximum power. Your sources are all digital which means you are already above 1vrms into your amp.
Let me pose the the question of why do you need a preamp?
@ajcrocker1 , this thread may help bring you up to speed on the OP's situation.
https://forum.audiogon.com/discussions/i-m-considering-replacing-my-passive-preamp-with-a-tubes-is-i...
He just tried a tube preamp (AI) and found that it sounded MUCH better than his passive preamp.