Tube info

But none of the European brands are cheap...

In a power amp the tube or tubes in the gain stage have the most influence on sonic signature. I've been told that the driver/phase inverters have little effect on sonics; eg, timbre, dynamics.
Not so, IME. The tubes in the driver stage have an audible influence on the sound (depending on the design of the amp). 

I'm in agreement with all the comments thus far to choose a good NOS tube for this stage even if it's purpose is simply to drive the power tubes.

These are all excellent suggestions. Anyone have any input on NOS Sylvania Baldwin Long Gray Plates?

Did I not call the tube the correct name? I referenced what I thought was called the driver tube. That’s what I always called it and the other tube is the rectifier? My understanding is the tube other than the rectifier has maximum sonic benefits. Is this correct?

What is the make and model of your amp so we can Google it.