Plug in preamp while amp is on caused very loud pop on speaker.

Did something really stupid this past weekend when I tried to rearrange the power cords and cables.  Unplugged my preamp while leaving the amps on and when I plugged back the preamp there was a very loud pop coming from my speakers.  The speakers played fine but is there any thing I should be concerned about the potential damage to the speakers?  Any suggestion is greatly appreciated.