This is not intended to be a full review. This was an impulse buy. I followed a link to a web retailer and noticed they had the black E1, so I jumped at the low price. What the heck, I said. I have previously purchased a Fiio E3, which I used for a couple of months and grew tired of.  I've been trying my new Fiio E1 out on my IEM mainstays: TF10, HF5, and RE0. I like it on each, although the most noticeable increase in SQ is with RE0.  The bass is so much better. There is nice rubbery texture, without boominess, meaning its not fast, but very present...