ok, forgetting about the bi-amp capabilities, and just from a tone point of view, does anyone have direct experience with both of these (the svt's) & care to comment on the differences? by the way, my svt6 died on me a month after i had it...cut to about 1/4 the volume. i assume it's a couple of tubes...fyi I was thining of replacing the svt6pro with an svt4pro...good idea?badidea? or the other option is a mesa 400+ comments? what i can't seem to find out is if the 400+ has a mte pedal input on the back (for tuning).. or a tune output...anyone know?