Short?

I have a McIntosh integrated hybrid tube amp / VPI table / Revel speakers.  When the AC comes on or off in the room i hear a loud pop.  I used to think it was a scratch on the album but now I realize its some sort of elelctrical issue.  I thought it might be a table grounding ussue but now it also happens occaisionally now when I'm not playing an album.  So does the amp need to be grounded?  And to what?  Thanks.