Hi, Sogood51. Yes, it very well could have been that my friend's system was a bit bright. Couldn't say for sure. And, absolutely it could have been the tubes that sounded more natural and lifelike. I'd probably agree with you here, but only in the sense that they were more truly conveying what was on the recording. :)
On the other hand, while I'm well aware of the theoretical possibilities of passive pre's, I'm hardly the first to suggest that reaching that ideal is another matter altogether. Remember, three listeners heard more things more clearly through the active, tubed unit. Why this was, again, I couldn't say for sure. Only that, in the end, all three of us preferred the Grid. Not only did we find it mor revealing and clear but it possessed a "rounder" smoother quality that was more pleasing. But, I really need to stress here -- I thought the Bent was an EXCELLENT unit and my quibbles are pretty minor. When I say that one wa more X than the other, it was by a pretty slight degree. But, again, I wasn't alone and regardless of theory, we all heard more through the other unit. (BTW, I didn't mention that two of these listeners were long time musicians, one with perfect pitch... My friend's wife has an excellent set of ears and doesn't really care very much about whether tubes were present or not -- and, the tubes were hidden from view in the chassis, anyway.)
So, who knows. As I told my friend while leaving, I'd be happy with either unit. And, if he wasn't going to purchase the Bent for the price he thought he could get it for, I probably would! :) Enjoy yours!
Andy