I hope this doesn’t come off sounding intentionally argumentative, but here goes: I often see the notion of inserting a tubed component into a system broached in terms of "adding" tube magic. I believe Ralph Karsten (Atma-Sphere) and other great tube electronics designers would make the argument that the "magic" of tubes is what they DON’T add to the sound of a system.
I use tubed electronics for the transparent, grain-free, dynamic, rhythmically-responsive, organic-timbre reproduction of the sound of voices and instruments the best of them provide, not for some tube coloration to be added to the sound of my system. Hi-fi electronics, tube and solid state, should "editorialize" as little as possible, not add a sound of their own to a recording or system. The objective is for them to have NO sound of their own. If tubes have a "magic" quality to them, it is in their ability to come closer to doing that than does solid state.