Yea it will definitely void. But it's not like ur amp is gonna die in the nxt few days. If really unsure bring it to ur local electrical store. He shld be able to fix it properly for u with no hassle.
Anyways i quote this from a friend la.
"Guitars, amps, pedals... all these stuff are built to last la. Unless u trash them, there's no way they can spoil."