Alledgely you can tell when it's on because everything sounds "warmer".[snip] There is an option to bypass the tube

Bypass... as in when you are tired of the tube-caused distortion that provides the "warmer" sound...

Maybe I'm just an anarchist at heart or something, but I'll take accuracy over the false warmth provided by tube amps. Besides, if I want more warmth, I'll just press the rocker switch that runs the motorizied voltage splitter that controls the input level of the amp that drives my 6.5" door speakers and bring the output of that amp up a bit (leaving the other four amps alone) and presto! More warmth. More brightness? Do the same thing with the switch for the center channel amp that drives a 4" coaxial speaker with titanium dome tweeter.

See attached .gif file for a signal path diagram of my system.

tanstaafl.