For my favorite guitar sounds, power amp saturation is an important element (Marshall, Fender, Vox and Engl - these are all EL34 power sections except the Fender that uses 6 x 6L6); the only exception is when I want more liquid/glass-like high gain tones, which I get from my Mesa JP-2C, the 6L6 power amp factors less in the sound for me.