Tube Sound Question

I think the amp accounts for about 80-90% of your potential tubiness.  

I would say the tubes used in either accounts for that whether it's the pre or the amp. Personally when I had the Octave V110 the output tubes made more of the difference.

I added a tube phono preamp to a solid srare power amp once and it opened up the sound in that holographic way that tubes can impart. So yeah, you could say a tube preamp can give the tubier sound in a pre-power pair. I'm all tubes now so not a concern.