There's probably a good reason, why this won't work but, could a set of 5 toggle switches be tied into some point of this circuit, to shut down pairs of power tubes? So that with one switch activated, 2 power tubes would be shut down, and total output would be 250w. and with 2 switches=200w./ 3=150w. /4=100w. and with all 5 switches activated we would have a 50w.amp? It sure would be cool to have real power tube saturation, at any volume.