I find the discussion about the new digital crossovers very interesting and plan on following it closely, just for the sake of new learnings, if nothing else. I think that I am pretty much an analog sort of guy with this aspect of the signal chain, but do look forward to learning more about it.
It wasn’t that long ago that going the passive tri-amp route was also foreign territory to me, always having used active crossovers before my amps. Now with my new system I am about as fully passively amped as one can get, and enjoying every moment. I also remember being concerned about what I had read regarding the dangers of passively biamping / tri-amping with tube amps. The idea is that if a tube amp sees the full input signal, they also need to see the full spectrum load on the output. Well, in a passive system that does not happen.
I had been using my old VTL Deluxe 100 Mono EL34 tube amps on my Martin Logan CLS1s and my Infinity RS1bs with an active crossover for years. I had tube failures here and there and thought that was pretty normal. Now I have them in a passive mode working the higher frequencies of my RM-V60s. I am using an original set of tubes for them that I had stopped using about 10 years ago, because I had several failures and assumed that they were all about to go. A friend of mine had picked up a tube tester and I found out that they still had a good bit of life left to them. So, I popped them in and it has been smooth sailing ever since I have owned the V60s. I know that the load to these amps is now much lower than with the older CLS1s and the RS1bs, but they must also like living on the dangerous side. It sure hasn’t hurt them a bit and they have never run better.