Moving the Soundstage; Help.

Looking for advise... I installed new Tung Sol EL34B's in my amp, burned them in, and they sound wonderful. The problem is the soundstage is now forward of the speakers. This has never happened with my system before, even with changes between SS amps, tube and SS preamps, cables. My system has always been laid-back with mid-concert hall seating; now I'm in the first row. Do to room size, I listen from 8 feet away in the near-field.
I'm using triode mode (30W push-pull) with all Mullard NOS small signal tubes. Sonics are textured, realistic, and dynamic with tight bass. Prior to this, I was using new production Mullard EL34's with Brimar input tubes. Sonics were textured, holographic, with a nice top-end, but bass was too light and soft.
 
It's an all single-ended setup with an Atma-Sphere UV-1 preamp using 1950's RCA Blackplates, short bottle. I'm using Gallo floorstanders with Purist Aqueous Luminist cables, all of which produce wide and deep imaging.
 So, my first thought is to try different 6SN7 preamp tubes to move the soundstage. But here's the rub, I don't want to make a change that will increase high-end extension.
Perhaps, changing room treatments? Any help is appreciated.