I've always heard that playing a bass through a guitar amp will cause damage to the amp due to it not being designed handle such low notes. I assume this damage would occur over time (not immediately) and would be primarily to the speaker. Is this true? If so, how hard would it be to "bass-proof" a guitar amp? Is it just a matter of swapping out the speaker? Or are there other differences in the wiring/tubes/etc. that must be accounted for, too? I know some guitarists use bass amps, just wondering what it would take to go the other way.