king,
In general I think you can get an idea of the basic characteristcs of a broken in tube with a few minutes warm up though it wont be at its best. Short a/bs many times will draw you to a more initially impressive piece but many times that gear isnt as "musical"I think the best results are judged over time. If you listen to a couple refernce pieces over a few nights then make a change you should be able to tell if you prefer one over the other. If you cant then you can go back to the quick a/b if you still dont have a preference flip a coin.
In general I think you can get an idea of the basic characteristcs of a broken in tube with a few minutes warm up though it wont be at its best. Short a/bs many times will draw you to a more initially impressive piece but many times that gear isnt as "musical"I think the best results are judged over time. If you listen to a couple refernce pieces over a few nights then make a change you should be able to tell if you prefer one over the other. If you cant then you can go back to the quick a/b if you still dont have a preference flip a coin.