I’ve had, and indeed still have, a number of their products, from their “Pro” series to their smaller units and some of their accessories, over the last couple of years and have generally been quite impressed with them.
I’ve written some reviews/impressions of them as well, which are a bit too lengthy to simply repost here - but here’s a link to my thoughts on the Pro iCAN, though. That link goes to SBAF, which has a ton of useful information, but is a bit different in tone and purpose to many audio sites (think of it as a private club/group of friends, with a very broad and direct sense of humor) - so if you’re of a sensitive persuasion tread carefully.
If you poke about there, and use their search function, you’ll find my thoughts on some other iFi products in some more broadly-addressed threads.
To summarize a few of them, here, though:
iFi Pro iCAN
I found, and still find, this to be an excellent headphone amplifier and pre-amp. It’s loaded with features, and if you make use of all, or at least most, of them then it’s pretty good value. Though waiting for the occasional sale when it’s price comes down to as low as $1,299 makes it even better.
I think it’s at its best if you have a small stable of headphones to pair it with, since it’s chameleonic nature makes it an excellent fit
It has both solid-state and tube-input stages, and you can choose between them on the fly (short delay between switching). The tube input stage has two levels of biasing that affect how much “tube flavor” you get. It’s very powerful, with up to 14 watts on tap, which is more than enough to drive any headphone, including things like the AKG K1000 and the HiFi-Man HE-6 & Susvara.
It operates as a fully balanced unit, with both XLR and RCA inputs and outputs. It has remote control volume. Supports 4-pin XLR, dual 3-pin XLR, dual 1/4" TS, 1/4" TRS and 3.5mm outputs. The 3.5mm output has an auto-functioning “iE-Match” feature, which makes it a better fit with very low impedance, ultra-sensitive, IEMs.
Then there are cross-feed and bass enhancement functions, which you can control the level of, and multiple gain settings.
Overall performance is excellent, and it’s entirely at home driving even flagship/TOTL cans. No, it’s not the very last word in overall sonics, though there’s a compelling density to it’s musical delivery, but it’s a great little unit overall.
iFi Micro iDSD BL
This is a compact, feature rich, combined DAC/amp, that also offers basic cross-feed, bass enhancement, USB->S/PDIF conversion, USB-input clean-up, iE-Match capability, the ability to operate on USB power or it’s own, big, on board battery (that can be used to charge/run other devices), a ton of power (up to 8 watts), selectable gain/power levels, and filter choices for the DAC.
You can use it as an all-in-one unit or just a DAC or just an amp.
It has line-outs/pre-outs as well as both 3.5mm and 1/4" TRS connections and a 3.5mm input.
The DAC itself has a nice, smooth, detailed and rich presentation. It’s capable of high-resolution conversion and supports up to DSD 8x (DSD512). The latest firmware allows support for MQA rendering (your player must do the first level unfold/decode).
The amp section is very competent and pretty quiet, though you’ll need to engage the iE-Match function for very sensitive/hiss-prone IEMs.
In all-in-one usage I found it took a couple of hundred hours for the unit to go from a “rather exciting” delivery, to something a bit more neutral and natural. Using the DAC or amp sections independently didn’t exhibit this.
Other than the size of the unit, which is a bit inconvenient for real portable (vs. transportable) use, the only real negative I found with it was the the volume pot exhibited marked channel imbalance at low levels. Using something like the Fostex TH-X00 I could have one channel playing and the other silent, and it wasn’t until about 10 o’clock on the dial that this went away. That’s pretty loud on the TH-X00 …
iEMatch
This is a neat little inline adapter, that works with both balanced and single-ended headphones/IEMs and allows you to help match them with sources of varying output impedance (particularly useful with multi-driver BA IEMs), increase effective impedance to reduce/eliminate hiss in IEMs, as well as maximize the dynamic range of your source into super-sensitive transducers.
It’s something I find very useful - but it’s situational … very much a case of seeing how a given source/IEM interacts as to whether it’s a benefit or not. For example, with the CA Andromeda I found it fairly effective in eliminating the hiss you get pair them with many portable players - but at the same time it would sometimes rob the music of “life”, and then it’s a bit of a toss-up as to whether you’re better off with, or without it.
Pro iESL
I’ve not done much with this … because it was apparent quite quickly that it wasn’t really capable of driving as wide a range of electrostatic cans as I wanted to experiment with (before buying a proper amp for them). It was okay with the SR-009 and even the 007, but with the L700 or the Voce it was just not driving things to levels that I considered useful.