The number of fallacies in those two sentences is truly boggling. Swapping inputs in your setup (you do have a selector switch) on your pre-amp shouldn't hurt anything. The fact you do not like blind testing simply rejects tested, established science about auditory perception, and that statement is not merely my "perception" it is an established part of human knowledge, so don't even go there.
A blind test can be as long as you want.
You don't have to actually close your eyes, to take a "blind test", and the literature on this, should you ever have informed yourself, would make you aware of the fact you've claimed 3 nonsensical things, along with your contempt for actual human knowledge.
Think I'm having a conversation with a directive teacher right now. Please don't take it all to serious
What is wrong questioning actual human knowledge and my perception of this ? Do you think we know the major part ?