I've got to say, after spending some time now trying to dial in the 9, it REALLY has a nice tube amp sound to it. I've been surprised that at pretty much all settings, it has a warmth to it that I didn't experience when trying out the 6. I haven't tried cutting the gain to minimum and cranking the pre volume...that may make for a more hifi sound. I prefer the warm sound, though...it's reminiscent of all the tones I liked from the 70s or so. Compared to the SVT 4 I used to have, the EQ is particularly sensitive, meaning there is a wide range of tweakability there, and the filter switches add a nice quick change. The SVT 4 was a great sounding amp, don't get me wrong, but I think the 9 has a wider range of possibilities from it's 'neutral' tone with everything at 12 o'clock. Not to mention it's about 45 lbs lighter! And although both were tube pre's, the 9 seems more tube amp tuned than the 4 was.