I used to use have a system just like the one you proposed. I was running a simple 6SL7-based pre-amp in front of a pair of Channel Islands Audio VMB1 monoblocks (40w/channel gainclones with pretty beefy power supplies).
I've moved on, mostly because I wanted to experiment with a SET amp. But there are things about the old system that I miss.
There was a clarity and purity about the music that I always really enjoyed. And it was super-dynamic. Even at very low volumes (like 60dB in the middle of the night), I always found the system really involving. Casually comparisons with much more expensive systems in local audio stores never got my toe tapping nearly as much as my own, low-cost system with the tubed pre and the gainclone monoblocks. The music was always loads of fun to listen to.
I've gone to a 5w SET amp now, and I'm happy with the change. The SET amp adds some weight and dimension to the music that was not there with the gainclone amps. I think I've given up a tiny bit in dynamics though. The gainclone amps I was using were extremely sensitive, and I think this came through in the music.
One word of warning, though. If the gainclone you're looking at is as sensitive as the CI Audio VMB1s (I think they reached full output on something like 0.65v), then you might want to choose your pre-amp carefully. With a source that puts out 2v (which is pretty standard) and a pre-amp that gives 20dB gain (again, pretty standard), you won't get much usable range on your volume control if your speakers are 90dB sensitivity or better. I was able to roll in some different tube types to reduce the gain in my pre-amp.
Chad
