well, for some time I've been thinking about this idea for the ultimately versatile power amp... but **** knows if it would work. I'm thinking of something like this - 4 EL84s, 2 6L6s, 2 El34s and 2 KT88s (maybe 2 KT66s? are they very different?). first - you can easily select between using any of the types of tube for different tones. second, and this is the main idea I'm hoping (but doubting) will work - you can switch in/out the desired amount of tubes! so, you want power tube distortion at the lowest possible volume - you just use 1 EL84. you want maximum clean headroom? you use two KT88s. you want marshall-esque power tube od, you use the EL34s, either one or two depending on where you are. see? so, let's say for instance that an EL84 is 8 watts, 6L6 is 20w, EL34s are 25w and KT88s are 30w, just for argument's sake. then you can choose between having an amp of 8, 16, 20, 24, 25, 30, 32, 40, 50 or 60 watts! yeh, so hopefully you see what I'd like to do, but is it possible? I mean, as far as my meagre (but growing) amp knowledge goes, i know it would have to be a Class A amp, seeing as you would be using odd numbers of tubes. or at least, it couldn't be class AB at any rate. i dunno, just gimme your thoughts, comments, call me an imbecile for even contemplating the idea, whatever. it'd be ****ing sweet if it did work though!