The Tube-o-later people have a new audiophile term; see the last sentence:
You will feel nervous when listening to the "harsh" device and you will relax when listening to the treated device. However, if you listened about 15 min. to the treated device and then switch back to the "harsh" device, it won't be as bad as before. Your sound perception has changed. When we recognized this strange phenomenon we coined the term "Ears been oiled".
Yeah, gotta watch out for old EBO.