Going Tubing

Greetings!

I would like to introduce some tubes into my two channel set up.

I currently have a solid-state preamp and a solid-state power amp. (And a separate, hybrid tube phono stage.)

I am wondering, conceptually, staying with separates, if it would be better to switch the preamp to a tube preamp, or if it’s better to change the power ramp to a tube power amp. With “better” in this case I mean would have bigger impact on, for a lack of a better description, “tube sound.”

(I realize there are other considerations, such as having enough power to drive my speakers, but here I’m talking about conceptually, which part of these two audio chain components would have the most impact on the sound if switching one of them from ss to tube.)