Of course I did some research before buying, but yes, I did a mistake. Reviews can say many things but all of them were positive so I tried it, just didn't liked it. Also, I didn't "yell", just expressed my experience with the unit, isn't that what this forum is all about? If negative = yell in your mind, then there is an attitude problem. I didn't bashed the product at all, just said I didn't liked the DAC sound in its stock config and that the tube was, in my opinion, a gimmick that was going against what I was looking for. Instead of buying tons of tubes for this unit, hence investing more on a product I am not liking at that time, I prefered to pay the shipping to return it and step up my whole setup instead. When you just spent 180$ on a new unit and you feel you have to buy aftermarket tubes to make it sound at least like your previous unit and you aren't even sure of the end result, it just turns you off, at least in my case.