I've received my iBasso T2, and after the first hours of use I'm ready to share my thoughts. My previous experience with amps has gone through the Xin Supermacro LE, Xin Supermini III and JMT Portable Pimeta.
I tried the Supermacro LE with a Kenwood HD10GB7 (headphone out), and the subsequent amps with the JVC XA-HD500 (headphone out and lineout).
The Xin's have been used with the Ety ER4, the Pimeta with modded Altec iM716. I'm waiting to get back my Altec after a recable. In the meanwhile I've thoroughly tested the T2 with my modded JVC HA-FX55. They are decent IEM <100$ which sound neutral. Great entry level IEMs, my main complains are the light bass and noticeable sibilance with some recordings. They also have very low sensitivity (almost like the ER4S in this regard).
My mp3 player has a 5mW+5mW output power, which is enough to drive the ER4P, and have some difficulties to give enough volume to the Altec and the FX55. The ER4P and FX55 don't sound as full as I'd like them to.
The XA-HD500 player behaves like a lineout at full volume, and has a separate lineout cradle.
I was very curious about the iBasso T2 since it's slim, has lovely looks and I can easily carry it in my pocket. I also have been disappointed with my former Xin amps, which didn't alter the tonal balance of my ER4P (switched to S) like I hoped.
The T2 is a nice surprise. While it can't be called "neutral", it adds a pleasant coloration to the neutral FX55. The T2 has been called tube-like by other headfiers, and I think its warmth makes it quite a unique portable amp.
The overall sound through my JVC FX55 features a larger soundstage, details can be heard more easily, and tonal balance becomes much warmer.The T2 has a noticeable midbass-lower midrange hump, and slightly recessed highs. Sibilance is completely lost with every track, but details in the highs are still easy to pick up, like when I listen to the player unamped.
Until now I've never considered myself a "believer" regarding portable amps, since I have been an Etymotic-detail addict and always looked for the right coloration for them, never being able to find it. I've now sold the ER4, but the T2 makes me impatient to get back the Altec iM716 and see if they match well with the iBasso, like what I'm finding the neutral FX55. The iBasso is actually making me want to get a new pair of ER4S.
The iBasso T2 has two headphone outs, a gain selector, a bass boost switch and a soundstage switch. While I didn't notice any changes with the soundstage switch, I want to elaborate more about the bass boost. It's a mild boost, definetely not bloated. It's perfect to make some tracks sound even fuller, and contributes to mate well with harsher '70s rock recordings, which will sound more ear pleasing.
Thumbs up for the T2. It's an amp that gives a warm, thick, tubey coloration, so it may not be a good match for already colored IEMs like the Atrio M5, Shure E500 or Triple fi 10 Pro (but I'll have to test it with the Triples as soon as I receive my pair). Ety userd will find heaven with it, since the T2 is able to give fullness to bright sounding headphones.
I wouldn't think to use the T2 with full size headphones. It is a IEM amp (this peculiarity is also shown on the metal case), so it may not have enough power to drive more power demanding cans. Anyway, this isn't the T2's purpose.
I'll elaborate more after I get my Altec back, and my Triple.fi find their way to my home.
Well done, iBasso!