When not handled properly, obsession with A/B tests is just as any another obsession turned into compulsion: harmful and self-sustaining. It ultimately stems from 1., lack of self confidence 2., lack of experience, 3., trust issues.
With these issues solved, it becomes meaningless whether you do a change blind or seeing. (Plus, you need follow up for it to work - break in period, different genres, susceptibility to line AC changes, etc, so just swapping as a form of A/B test is shallow at best.)
When listening to music / system, I just open myself to experience without pre-judging the system. Why? Because I heard cheap solutions punching heavy weight and ultra-bucket mortars turning out as duds, and one piece that sounded like a rust bucket singing in another system. I learned that we cannot bring a single preconception to a listening experience, and I have zero trouble accepting that.
So, go in with zero conceit and preconceptions. Seeing the box that I will hear will bias me to judge it AFTER the hearing on a different scale. (Should have done more or punched high above the weight).
After all you only truly need an AB test when you are a MANUFACTURER and you want an edge to sell.
