Mesa recently had the pleasure of spending some time with Alex Lifeson and his guitar tech, Scott Appleton, to take a tour of Alex's rig for the 2012 Clockwork Angels Tour.
Mesa/Boogie Blog Post: http://mesaboogie.com/news/?p=4388
Scott does a great job of walking us through the rig and discusses how the Mark V and other amps in the rig are used and routed. He also shares some additional details on some of the cool things they do to deliver the guitar sounds of RUSH to you, live.
For more details, settings, pictures and an interview with one of Alex's longtime friends and an engineer with the band over many great Rush albums, check out the Mesa Blog: