I've heard that in most amps that have 2-4 output tubes, you can pull a pair, or even 3 of the power tubes to reduce wattage of the amp. I am a fairly advanced amateur DIY guy, but I can't get my head around how this can be ok. But the person who told me you can do it is in EE and has off the charts knowledge on most things. So, on my classic 30, or other normal push/pull type amps, IS IT OK to just pull tubes to reduce power? And, I know there have to be some side effects, so what are they? I just keep thinking impedance will be screwed up somewhere, voltage flowing around in open circuits.... something bad has to be involved.