Its not that hard. You run it good and long with nothing connected. Then when you're really sure its run long enough you hook it up and listen. Then if you still hear it change and get better, which you will, then guess what?
Unfortunately we never will get any agreement on the answer. Instead of admitting yeah gosh open circuit, what was I thinking? people will make up any excuse for why the sound continued to improve.
Assuming of course they even notice. Its one of the bigger more fundamental problems. People with monster listening skills have been hearing this and knowing all about it and it never even comes up. People who don't have to ask- and then make things even worse. Because instead of doing what they should be doing- playing the darn thing and listening to it, learning to hear first hand what's going on- they throw a dart, pick something to "believe" in, and miss out on yet one more opportunity to develop as an audiophile.
Lather, rinse, repeat.
