The recordings were engineered by Alex Gaziano. Thanks Alex!  I couldn't have done this without your help. Alex used a very minimalist approach when recording the amps.  He used an SM57 in the close mike position and a Carvin condenser microphone about 6 feet away to pick up the rooms ambience. 

Alex just mixed them together (and perfomed his magic).  There were no effects added.  I think the recordings accurately reflect what the amps sound like.