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. I bought a Schiit Valhalla and a Odac, which obviously is on an other price level.
Maybe I should have said what I was coming from too. I had a Fiio E10, a 70$ unit, and I much prefered it's sound to the T1. 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.
I'm not sure what you mean by gimmick when that's the whole point of this dac. I'm glad u found what you like with the valhalla and Odac well because like you said they are on another price level and if even that doesn't please you, i don't think anything would :D
Anyway. At first I found the stock tube okay, but after changing to better ones I couldn't go back anymore. I'm not a good critical listener, but I can at least hear that the stock tube doesnt have the wider soundstage of better tubes(i'm using Tungstram E88CC now). I did find the bass lacking in quantity at first coming from a Xonar DX, but gradually started to appreciate it as it allows other parts of the frequency to come in more. Personally i like how this pairs with my HD600 as contrary to what people describe, i find it a dark phone with rolled off treble and this sorta balances it out. I find not only the amp section bright, but the dac too because I use line out to my A2s and found the same thing (compared to my DX). So yea, the bright DAC+amp pairing with bright headphones would not be very nice..