If you are intrepid and the least bit mechanically inclined: you should be able to open the amp and tighten the 5 Way's mount nut. Many amp-output wire terminals (usually, "ring" type) are connected to a threaded post, on the amp's speaker terminals, held on by a nut, that also tightens the mounting. You simply loosened that, when changing the cables. If you do open the amp, before reaching into it: REPEATEDLY DISCHARGE the power caps, by shorting from one terminal to the other. Wait an hour, between those dischargings, and repeat until there's no more indication of voltage. If you don't and ground something, you can hurt the amp, or- at least blow a rail fuse. The typical SS amp only runs it's outputs at 80V, or so, but- that can still bite you pretty good. Tube amps are another beast, entirely (potentially: life-threatening)!