Originally Posted by: bbzswa777The wall of Marshalls is exactly what I was thinking of. So I guess those guys weren't exactly using a PA for all those lol

Although there are some players that actually use more than one, for the most part that is an illusion. Sometimes, only one amp is active & cab is miked. More often everything on the stage is for show & the real head & cab being used is off stage in a rack where the guitar techs can get to it quickly & replace or fix it.

And then there's some of this.

http://cdo.seymourduncan.com/blog/wp-content/uploads/a.jpg
http://www.makenmusic.com/blog_v2/wp-content/uploads/2014/06/dummycabs.jpg

Google "fake wall of marshall amps". :)