While you are voicing the amp try to decouple it from the floor, possible on foam yoga blocks or a chair.
It's all those little things that make hunting for the ultimate tone like finding the holy grail. Didn't the history channel say it was in florida? lol
Personally I gave up on that quest and went another route. Amp collecting, a tone for every occasion
 Now instead of sinking all my time and $ into one amp I get to do it to a bunch of them and upset the wife with all the space they take up.
  Now instead of sinking all my time and $ into one amp I get to do it to a bunch of them and upset the wife with all the space they take up.