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iFi iDAC DAC / headphone Amplifier

  1. Turrican2
    Amazing clarity and hefty bass
    Written by Turrican2
    Published Jun 11, 2014
    Pros - The detail retrieval is astonishing, feels very solid and well made, relatively inexpensive
    Cons - position of RCA/USB ports, no s/pdif input
    I first heard the iDac at the April 2013 head-fi meet in London.  It was part of the full ifi stack (at the time) consisting of iUSB, iCAN and iDAC.  I was amazed at the quality of the sound from this miniature setup and knew right there and then that I was going to own at least some of this gear.
    Until recently I've been listening to my AKG K3003 and Hi-Fi Man HE-500 with the following setup:
    iCan -> iTube -> Rcam rDac -> Squeezebox 3
    As the Squeezebox 3 only has s/pdif out (no USB) I could not add the iDac as that would mean also buying a squeezebox touch, which at the time was out of my price range.
    Fast forward a little and I now have the Squeezebox touch and hence USB!!  - enter the iDac
    As I have the iRack also, the iDac fits perfectly into my stack, that's one of the things I love about iFi, their gear looks as good as it sounds.
    Hooking it up
    I find the connectivity to the iDac a little tricky.  Having the USB port and the RCA ports on opposite ends makes for potentially messy looking cable configuration.  It  would be much handier to have them all on the back.  As it is I am using this purely as a DAC so slid the iDac in backwards to the rack, on the bottom shelf, that way I can feed the USB cable under the rack, looks pretty good.

    Before I could use the USB port on the Squeezebox touch, I had to install EDO (Enhanced Digital Output) which is a free plug-in:
    1) Ensure your Squeezebox Touch is running 7.7.x or later firmware
    2) Go to Apps Gallery -> 3rd Party Apps on the touch screen
    3) Deselect the "recommended applets only" option, so that you see a longer list of apps
    4) Select "Enhanced Digital Output" and select it for installation
    5) Your touch should download the app, reboot, then download a new custom linux kernel and reboot again
    6) You should now get a list of possible output devices - this should include "Digital Output" and your USB Dac if it is plugged in, select the appropriate output
    7) Touch should reboot again and then be ready to start playing with the selected output

    If you want to change the output go to Setting > Audio Settings > Digital Output; if you want to change some of the advanced options go to Settings > Advanced > Digital Output.
    First thing I noticed was the BASS!!  I had been running my iCAN with full x-bass (level2) with the rDAC and that was a great sound for me,  With the iDAC  I had to knock it down a notch, it was just too much.  Level 1 x-bass is perfect with both the HE-500 and K3003.
    Compared to the rDac the detail retrieval is much better, I'm hearing things I've never heard before with very familiar tracks.  I find electronica in particular is a lot more musical with the iDAC leading to much longer listening sessions.  I do love listening to gear which invites me to re-discover my music collection.  DACs are improving so quickly, great news for us consumers.  

  2. Faber65
    Exactly what I was looking for
    Written by Faber65
    Published Apr 21, 2014
    Pros - Very detailed but not fatiguing, very good PRaT, tight control extended to the bass
    Cons - Not found yet
    I spend my working days far from home and I was looking for something compact with two specific characteristics: keep the same feeling that I have when I listen to the Sennheiser HD650 driven by the Burson Conductor and have a non fatiguing and yet detailed sound to cool me down after a long and tiring working day.
    During the SIAV exhibition in Shanghai last weekend I had the opportunity to try the iFi iDAC and at the first listening I understood that this was the stuff I was looking for: love at first sight.
    I purchased the iDAC on the spot and I completed the system by adding the iUSBPower to clean the signal, the Gemini and the Mercury cables, and the iTube as a preamp.
    The package makes the music flowing from my M-Audio BX5D2 powered monitor speakers in a very smooth and natural way, the PRaT is excellent and the bass firm and under control even at high volume.
    The sound is very detailed, somehow punchy and yet not fatiguing, in other words: believe me or not but with or without the iTube, my feeling is that this iDAC sounds more analogue than digital.
    Even if the performance level is obviously not the same, the Sabre ES9023 of the iDAC shares similar sonic characteristics with his sibling ES9018 Reference chipset used in my Burson Conductor. 
    Amazing value for money if we consider that the combination iDac+iTube is one quarter the price of the Conductor, which in my opinion remains the reference headphone amplifier in his category.
    Of course the iDAC itself is not powerful enough to drive the HD650 in the proper way (the iCan amp module should be added), but it works very well with the MM450X that I use for my conference calls, to have quieter flights and also to listen to the music.
    I am looking forward to listening what I can get from that system after a longer shakedown period (and with better monitor speakers [​IMG] )
    Bravo Thorsten Loesch, good job iFi.
    1. hk6230
      Cool. I owned the iTube. Your brief review makes me want the iDAC and iCAN, too.
      hk6230, Apr 21, 2014
  3. Quadpatch
    Sleek USB Sound, Easily Transportable
    Written by Quadpatch
    Published Sep 9, 2013
    Pros - Neutral, Neat, Nice Volume Dial, All Metal
    Cons - RCAs on the front, Wish the headphone connection was the larger type
    Here is my review of the Ifi iDAC - originally posted on my Blog - http://noblehifi.blogspot.co.uk/
     Disclaimer: A big thank you to Ifi for loaning me the iDAC for this review!

    The iDAC is a combined DAC and headphone amplifier. The ESS 9023 Sabre DAC and class 2 Asynchronous USB is capable of decoding audio up to 24bit 192khz. Being over the magic 96khz it requires a driver to function on a Windows PC, but it will work out of the box on an OS-X Mac or Linux system. It shares the same aluminium chassis, shape and styling as the rest of Ifi's 'Micro' range and weighs in at 193g. The back-plate houses only the full-size USB-B connector, so the RCA connectors are up front with the volume and 3.5mm headphone jack. There is no power input or switch since the unit takes it's juice from the 5v USB bus (whenever it's connected to a USB port that's supplying power the iDAC will be on).

    I was really happy with the sound quality from the iDAC. It's a huge step up on any computer's default audio and it competes well with other similarly priced units. The amplification is also very good for a unit of this size / price. It doesn't quite live up to the levels of the dedicated & powered iCAN (which is understandable), but of course you can use them together if you so wish. 

    The iDAC alone has a sound that's very clean, smooth and detailed. Neutrality is quite a stong point for the iDAC because it seems to suit a wide range of headphones equally well. Bass feels tight and kicks hard, without feeling bloated. Mid-range feels smooth and detailed. While treble is exciting and articulate, without any sensation of harshness. Soundstage is also really good, feeling enjoyably wide / dynamic and giving open headphones an impressively spacial feeling.

    I had no issues dealing with bit-perfect audio at any settings. Unlike some USB DACs that insist on certain sample rates or bit-depths; like the Fostex HP-A3 or Arcam r-PAC respectively. I was able to dynamically shift between different audio format and system setting without much pause or any need to restart software (Foobar), so it seems the drivers are indeed pretty solid on the Windows platform. 

    Power wise there is plenty on tap here for all be the very hardest to drive headphones, while sensitive headphones don't suffer from gain distortion or fiddly volume settings. 
    I have tested quite a few headphones with the iDAC straight out of my laptop and I am very impressed by it's abilities. Most recently I have been playing with the Hifiman HE-500s and I have been very impressed with that combo indeed. I wish I could plug them straight in, without needing an adapter, but oh well. The sound was deep, energetic and smooth. A very nice match for the HE-500's sound. 

    The Mad Dog is another Planar Magnetic headphone that's a good test of amplification and this also had no issues getting enough juice out of the iDAC. Now this is a headphone is nothing like the HE-500. It doesn't have the crisp kicking bass, nor does it have a midrange that excites in the same way. It's a very flat headphone that can feel a little dry at times, but it's bass is great when you get used to it. This is driven equally well by the iDAC. I was surprised that it needed more power than the HE-500, but 50% was still often enough to split your head open. 

    Sticking with larger headphones, but moving to dynamic drivers I picked up the Denon AH-D7000 to see how the iDAC deals with it's warmth and wobbly bass. I think it's possibly that the iDAC is tightening up the bass a bit here compared to something like the Schiit Modi and Magni. I usually like amplification adding a bit more upper bass heft, if it's done well, but here I really like how the Denon is handled. It doesn't overemphasize the mids, but it does make it feel a bit faster and better for Rock and Pop than it often does. The smoothness of the amplification also adds nicely to the warmth of the headphones without turning into a mushy mess. All in all I am very happy here, accept again I needed that step-down adapter connection.

    The portable Sennheiser Amperior also gave me a lot of enjoyment, despite their overzealous upper bass emphasis the iDAC does wonders to push the quality of this small driver. I really enjoyed this combo for Rock, but also Soundtracks and movie watching because of it's power and speed. These 18 Ohm headphones are driven to high volumes on the iDAC with less than 1/4 turn on the dial, but the potentiometer is so nice and smooth that precise power is still not an issue.

    There are quite a few devices around for the iDAC to fight with. From all the things that I have tested recently the Fostex HP-A3 is probably the closest match. The iDAC doesn't have the optical input or output that the HP-A3 does, but I don't see this as a big loss, actually since I never use optical it's a plus for me because the iDAC can concentrate on it's USB. Both machines are only powered by the 5v USB bus, but considering this they both produce a very refined sound and can even drive demanding headphones to loud volumes easily. I do prefer the larger headphone connection and rear RCA connectors of the Fostex, but then I prefer the slimmer chassis and smooth metal volume control of the Ifi, so there's no clear winner on design and build for me. 

    Purely talking audio quality I would give the nod to the iDAC because it feels a little more capable in the bass department, although both of these machines are more about detail than warmth the iDAC feels a little warmer at not much expense in the hard edged detail department. It feels like a nicer balance for a majority of my headphones and that's quite something since the HP-A3 is very good also. 
    I should point out that I don't have a lot of high-definition audio to test the benefits of 192khz sound. I have one album in this standard and less than a dozen in the 96khz format. Most of my music is either in lossless CD or maximum quality compressed CD (Spotify premium) format. The iDAC did a great job with all of this and had no technical issues whatsoever. I'm not one to shout about the benefits of HD audio quality though, as I'm not convinced that I can sense it. On the flip side; I am pleased to see the iDAC support 192khz audio, even if it does mean I have to download a driver to make it work. 

    Trying to connect the iDAC to my android phone (Samsung Galaxy Note 2) proved unsuccessful. Normally I would put this down to the iDAC needing the full 5v that a computer can provide and the phone cannot, but this time I cheated and used Ifi's Gemini cable to provide the power and still I could not get the Note 2 to drive act as a digital transport for the iDAC. I know this works because it was successful using the Gemini the same way with the Schiit Modi. This is a rather unlikely combination to use, but just to let you - it doesn't work. Now Samsung uses it's own digital audio format on the Galaxy phones, so I'm not too sure what the issue is here.

    The basic design of the Ifi chassis' are the basic tube - with two plates screwed on, but they're made from nice aluminium, which deals with heat well and they feel like solid quality. Their design is just different enough to keep things interesting. They also stack quite well, although in the case of the iDAC you could feel like it doesn't need to be combined with any of it's brothers, I can tell you that it's certainly not a bad idea. The iDAC follows the same design as it's family tree, but it's the only model that doesn't require a power connection so all you get on the back is USB - B port. This gives the iDAC all the power (5v) and data that it needs. 

    The analog RCA outputs are placed on the front of the unit, which is a little odd. When I used the iDAC for speakers I just turned it around and lived with the USB being untidy. Since the volume control wasn't required any more this wasn't too bad, although ideally I would have preferred them on the back to keep things neater in general, but it's not the end of the world.

    The headphone connection is the smaller type (3.5mm / 1/8"), which is OK, but on anything costing this much I usually prefer to see the larger (6.35mm / 1/4") connection. I experienced some crackling in the audio when I moved the connection while using adapters for larger headphones. This happened with simple adapters and cable adapters that work fine with other equipment so I can only put this down to the connection, but it didn't seem to happen hardly ever while using headphones with the smaller connector. In general use this issue didn't really bother me, but it was easy to repeat if I fiddle with the connection.

    The metal volume dial is as smooth on the outside as it is to turn. The mechanism is nice and tight too, which makes it easy to get just the right volume - even with very sensitive headphones (less than 25 Ohms). I don't get on with in-ears so I can't contest that the sensitivity is quite enough to cope with them, but it certainly seems like it could be fine.  
         FINAL WORDS
    The iDAC is a great little machine than can be driven from a small laptop (or even a Windows tablet), its high quality amplification can easily drive demanding headphones to loud volumes too. You'd be hard pressed to beat this thing for the money and if you want to improve the sound further later on there are plenty of options in the Ifi catalog that work with it well. 

    I like how it's not over complicated with other inputs and outputs, although I do wish the RCAs were on the back and the headphone connection was the larger type, but if none of these details bother you then I highly recommend it. 

    Custom Desktop PC, Dell Vosto Laptop, Ifi iUSB, Ifi Gemini, Ifi iCAN, Schiit Magni, Schiit PYST, Epiphany Acoustics Atratus, Denon AH-D7000, Hifiman HE-500, SoundMAGIC HP200, WeSC Chambers RZA Premium, Mr. Speakers Mad Dog, Sennheiser Amperior, Samsung Galaxy Note 2
  4. pro1137
    A Masterpiece in Sonic Performance
    Written by pro1137
    Published Aug 14, 2013
    Pros - Transparency, built-in amp, appearance, accessories
    The iFi iDAC provides a flawless sonic experience that is truly high-end.

    Big thanks to Avatar Acoustics for the review sample!

    The iDAC comes with a very nice USB cable and RCA cable for line-out. 

    This DAC has, by far, surpassed my expectations. It provides the finest of audio experiences.

    Everything sounds super-transparent and life-like, like most ESS Sabre DACs. What is truly impressive about this DAC is the full 24/192 support.  

    Headphones that I tested with the iDAC

    Beyerdynamic DT770 Pro
    Takstar Hi2050
    Audio Technica ATH-M50
    Audio Technica ATH-A700x
    Philips Downtown
    Rockit Sounds R50

    From what I can hear, the iDAC performs and powers extremely well, especially considering it is directly from USB power. Sure, iFi has a separate USB power supply product for sale, but unless you truly want to get the very maximum out of the iDAC, I wouldn't see a reason to get it. iDAC is completely clean as it is.

    Gain - I can only detect a slight amount of hissing when the DAC is turned up to around 12 o'clock or more on low-impedance headphones. IEM users need not worry! I don't truly see the need to include a gain switch like others have said they want. It'd just seem redundant to me.

    Soundstage - Soundstage is rather impressive to me. I've heard a few people saying that it didn't impress, but that's not what I got from the iDAC. I can hear where instruments are supposed to be, what they sound like in terms of the venue they were placed in, and so on. It just sounds 'right' to me. 

    In conclusion, I highly recommend this product to anyone looking for a good semi-budget DAC. It is a real competitor in this price range, and has no significant flaws that I can see.

      Rafik Moses likes this.
    1. Rafik Moses
      It is just a piece of art in audio filed.
      Rafik Moses, Apr 8, 2014
    2. Rafik Moses
      It is not just a masterpiece but it is a big step to get the unmatch sound quality.
      Rafik Moses, Apr 8, 2014
  5. ClieOS
    ESS Sabre based DAC with excellent transparency.
    Written by ClieOS
    Published May 30, 2013
    Pros - A good headphone amp section wiht a clean, fully transparent line-out. No hiss at all.
    Cons - No gain control, shape of housing.
    iFi Audio is a new comer in the headphone amp scene, but it does share the same bloodline as the renowned U.K. based premium audiophiles brand AMR. While AMR already has some top end gears to offer to the speaker and full rig owner, its little sister brand seems to aim toward mainly the computer based headphone user as well as minimalist audiophiles. Their current ‘Micro’ line of devices includes the iDAC (headphone amp + USB DAC with line-out), iCAN (headphone amp), iUSB Power (USB isolator), iPhono (phone preamp) and the recently released iLink (USB to S/PDIF converter). We will cover the former three here, which are priced at US$299, US$249 and US$199 respectively (*price do vary quite a bit depends on region though).
    Front (from left): iUSB Power, iDAC, and iCAN.
    Back (from left): iCAN, iDAC, and iUSB Power.
    DAC section:
    ESS Sabre ES9023 DAC chip, fully supports up to 24bit, 192kbps resolution
    XMOS based USB Audio Class 2 Asynchronous solution
    Signal to Noise Ratio: >111dB(A)
    Dynamic Range(-60dBFs): >111dB(A)
    Crosstalk: <-102dB(1KHz)
    Total Harmonic Distortion(THD): <0.005%
    Jitter: Below measurement limit
    Frequency Response: 3Hz to 33KHz + 0.1dB/0.3dB
    Output:  Line-out, RCA jacks
    Headphone amp section:
    Opamp: MAX9722
    Output Power: >150mW (15Ω)
    Output Voltage: >3.3V (>100Ω)
    Signal to Noise Ratio: >97dB(A) (400mV/300R)
    Total Harmonic Distortion: <0.003% (400mV/300R)
    Output Impedance (Zout): <1Ω
    Power Consumption: < 2.5W
    Dimensions: 158(l)x68(w)x28(h)mm
    Weight: 193g(0.43lbs)
    Output: 3.5mm Stereo Jack
    Gain stage: Fully discrete, Class A
    Buffer stage: TPA6120A2
    EQ: two levels selectable 3D Holographic Sound and XBass
    Signal to Noise Ratio: >117dB(A)
    Total Harmonic Distortion (THD): <0.003%(400mV/150R)
    Frequency Response: 0.5Hz to 500KHz(-3dB)
    Output Power: >400mW(32Ω)
    Output Voltage: >5V (>600Ω)
    Input Voltage: AC 100 - 240V, 50/60Hz
    Power Consumption: < 4W idle, 10W max.
    Dimensions: 158(l)x68(w)x28(h)mm
    Weight: 216g(0.48lbs)
    Input: RCA and 3.5mm stereo jacks
    Output: 6.4mm stereo jacks.
    iUSB Power
    Two USB sockets: one data and power and one power only (*for use with iFi Gemini cable)
    Output Voltage: 5V±0.5%
    Output Current: 1A
    Output Noise: 0.1uV(0.0000001V)
    High-Speed USB 2.0: 480Mbps
    Input Voltage: AC 100 - 240V, 50/60Hz (Ultra Low-Noise Power Supply included)
    Power Consumption: < 9W (includes powered USB device)
    Dimensions: 158(l)x68(w)x28(h)mm
    Weight: 195(0.43lbs)
    Accessories and Build Quality
    iDAC comes with simple user guide, some stick-on rubber feet, RCA cable and 2 feet of really good quality USB cable (A-to-B). iCAN comes with user guide, rubber feet, 6.4mm-to-3.5mm adapter, RCA cable, 3.5mm interconnecting cable, as well as a 9V power adapter. iUSB Power comes with the same 9V power adapter, rubber feet, user guide, USB cable as well as an USB-to-barrel plug cable. Oddly there is no mentioning anywhere about the function of the USB-to-barrel plug cable - but given the barrel plug has the same diameter as the 9V power adapter (which comes with both iCAN and iUSB Power) and it certainly can’t plug into itself, the reasonable assumption is that the cable is meant to plugged into the power only USB port at one end and iCAN on the other, serving as iCAN power supply – I tested it and it works just as assumed (* it might work with iPhono as well but I have no mean of testing it). Anyway, there seems to be no degradation of SQ by using iUSB Power as iCAN power supply based on brief listening. It is actually a very neat feature, especially when you are using iUSB Power to connect to iDAC then iDAC to iCAN. It helps to eliminate the need of an extra power adapter – however, it does come with a cost and we will discuss it on the next section. Another fun fact is that I can use this cable with a portable USB power bank to power up the iCAN and function almost like a portable amp – ‘almost’ because the sheer size and weight of iCAN + external battery are too much for portable use.
    [UPDATE] From iFi: the USB-to-barrel plug is intended for Squeeze Box Touch.
    iUSB Power
    Build quality is top notch. The whole Micro line use the same high quality, almost tank like aluminum housing, which is a bit too long if I am nitpicking. The real issue is that the long and narrow housing kind of limits where all the sockets can be placed. I can’t say these are the most sensible of design, but they are not terrible enough to stop me from using them. It is just that I have an urge to want to stack them up but the looping of the cable from front to back - well, isn’t exactly aesthetically pleasing. Beyond that however, I can say that all three units are excellent in quality. The (top and bottom) marking on the housing really gives them a premium look and they are not cheap, easy-to-scratch paint job.
    Gain and Hiss
    Gain on both iDAC and iCAN are on the high side. No official number that I know of, but my basic measurement shows that iDAC has a gain of around +15dB, with a max output of around 4.7Vrms. The line-out is a fairly standard 1.95Vrms. For iCAN, gain is about +17dB with max output of around 6.67Vrms (*iDAC as source).
    With such high gain, volume tends to get too loud too fast when a low impedance, high sensitivity IEM (or similar full size) is used. With Shure SE530, I can barely go pass 8 o’clock on the iDAC’s volume knob. But on such a low position, the problem of imbalance inherent in all potentiometer becomes quite apparent. At the end, I have to lower the software volume on the PC to get them to play nice together. iCAN also doesn’t fare much better as well. It would have been great if there is a gain switch on both devices. On the upside, both have plenty of power to drive high impedance headphone without a problem. This is especially true for iCAN. [UPDATE JUNE 5th 2013] iCAN has been revised with selectable gain switch now.
    Hiss prone IEM (i.e. Shure SE530 again) can pick up minor hissing when the volume knob is turned close to 12 o’clock. However, this shouldn’t be too big of a deal since it is almost impossible for sensitive headphone to get this loud in actual use due to the high gain. In any case, IEM user must take note if your main IEM is low impedance, high sensitivity and hiss prone – while both iDAC and iCAN will still work, they might not be the best option in practice.
    On previous section, we talk about using iUSB Power for both iDAC and iCAN at the same time to eliminate the need of an extra power adapter, but it comes with a cost – that cost is hiss, and in quite a noticeable level too. This is likely because any benefit of isolating the USB ground from the iUSB Power is lost. So at the end, it is still better to stick to the stock power adapter.
    On the topic of stock power adapter - iFi Audio seems to be especially proud of it. They call it the ‘ULN’, or Ultra Low-Noise adapter. It is based on switch mode circuit, which is traditionally considered to be much noisier* than linear circuit (*due to the ripple created by the fast switching nature of the switching circuit), but have the advantage of being inexpensive and more versatile in application. In the case of ULN adapter however, iFi Audio has taken the time to craft out an adapter of exceptionally low noise (and they have shown measurement done on various adapters with tech paper). Based on my poking around of the inner on all three models, I also notice they have put a lot of know-how into noise filtration and elimination on the power line – not just on iUSB Power, but also on iDAC and iCAN. All and all, I am pretty impressed by their attention to detail on the power section.
    Sound Quality
    RMAA measurement on both iDAC and iCAN show no issue. In fact, iCAN performance has excessed the resolution of my measuring setup so it looks pretty much perfect. While the headphone-out on iDAC doesn’t measure as well, it is still considered excellent by my standard (low noise, flat FR curve, etc). Output impedance on iDAC is too low for my measurement, which is of course a very good thing. On the iCAN, it is about 1ohm (*more on this later). Both have excellent current output into my usual 47ohm and 23.5ohm fixed load test so that’s not a problem as well.
    iDAC underbelly.
    Let talk about iDAC first. The internal DAC chip is the ESS Sabre ES9023, which is the most common DAC among the ESS line-up. We have seen it on really budget USB DAC like the HiFimeDIY’s Sabre USB DAC and Stoner Audio UD100, to the more modestly priced ODAC and some really expensive DAC. On the DAC section alone, some of the more standout features of iDAC include the full 24bit, 192kbps resolution and USB asynchronous mode. These are done by employing a XMOS microcontroller with 3 reference clocks (one for USB and two for sampling rates). The USB power line also seems to be internally regulated so a little bit of ‘dirty’ USB power shouldn’t be an issue. While these are all good on paper, I have to say that these features are not something obvious to the listening. To be honest, how many can tell a good jitter from a great jitter, or a somewhat dirty USB power line from a clean USB power line? I am not sure I can. If we were to talk about just the actual sound of the line-out, it does closely resemble that of ODAC or UD100. It is not a case where you will say ‘wow, this ES9023 sounds better than the rest’. No, they all sound darn good – clean, transparent, well resolved, and those are things you can expect from any well implemented ES9023.
    The real interesting bit about iDAC is in its headphone amp section. It uses a MAX9722, which is hardly a top range opamp. But the key is in its implementation, as it sounds good enough to give me the impression of iDAC being ‘ODAC + O2 roll into one device'. Okay, frankly speaking the headphone amp section still isn’t quite beat the O2 in overall performance, but it is really close. It carries the same flavour of top quality transparency in its sound. The only two noticeable areas that are not quite on par are: First, the overall image on the iDAC headphone amp not being quite as large and grand as O2. Second, the bass hit is a tad softer. Try to scale the O2 down 10%~15%, and that’s what you will hear on iDAC. Still, it is admirable and could even compete head-to-head with some standalone sub$150 amp on its own. I’ll call that a win for any headphone amp section built into an USB DAC. If I were a minimalist, I would have been very happy with just the iDAC alone.
    iCAN underbelly
    iCAN is also an very interesting piece of gear of its own right. By looking on the inner, the ‘Class A TubeState’ section is, as far as I can tell, a fully discrete gain stage, then it employs TPA6120A2 as the buffer stage. If anything, TPA6120 has a good reputation on its sound quality and raw power, but almost always being dissed for its high output impedance. The minimum 10ohm output resistors needed for stability put TPA6120 into obvious disadvantages when it comes to low impedance headphone (*lack of electrical dampening) and even worst, low impedance multi-driver headphone with passive crossover (*coloration). But iFi is clever enough to use inductor bypassed by a small value resistor to achieve the same stability without any of the downside.
    So how does it sound? In sum, identical to O2 – and that’s the highest possible complement I can give to any headphone amp(*for those who don’t know the O2 – it is a headphone amp designed with measurement to deliver the best possible transparency and performance to any sub 300ohm headphone). It is hard-pressed to find any difference in their sound when volume matched. The same authority, control, power, resolution and soundstage are shared between the two. There is no sound signature to speak of, as both are totally transparent and neutral in flavor. With the 30+ amps I have owned, just  a small handful of them are able to partially match O2 in overall sound quality, and only iCAN can deliver near identical performance. They are, in my opinion, true ‘reference level’ headphone amp for others to measure up to. But the story doesn’t end there – beside top-notch sound quality, iCAN has two very functional EQ as well: the 3D Holographic Sound and XBass. We will discuss more on them in the EQ section.
    iUSB Power underbelly.
    Confession: it is never my intention to get the iUSB Power to use with iDAC (or iCAN) in the first place. I needed a good USB isolator for other application and iUSB Power fits the bill. So there is no expectation that it will improve the SQ of iDAC. In fact, my PC has really clean USB power so I never run into trouble with any of my USB DAC before. But since I have it, might as well use it for its original intended purpose. RMAA measurement is carried out on both iDAC’s line-out as well as on UD100, with and without the iUSB Power, plus with and without isoEarth (ground noise elimination system) engaged. Result? Well, nothing is really different between the measurements. Audibly, I also can’t detect any difference on both UD100 and iDAC line-out as well. My conclusion is, since I know I have really clean USB port in the first place, any benefit from the iUSB Power should be minimum at best. But the story didn’t end there – does iUSB Power brings any improvement to the setup? Yes, it is to the iDAC’s headphone-out. As I have said previously, iDAC headphone amp section is like a scaled down O2. With the iUSB Power however, the soft hitting bass get turn up a notch and the overall soundstage opens up, especially in the depth. It seems to take on a slightly different personality than just a ‘baby O2’. It kind of reminds me of JDS Labs’ C421-AD8620 more than O2, but it is certainly closer to the performance level of O2 than before. My guess is, since PC’s USB port is limited to 500mA while the iUSB Power can supply up to 1A, the improvement of the headphone amp section is a sign of the extra juice. The reason why neither UD100 (which only outputs line-out) nor iDAC line-out show any difference is because neither of them is designed to output current, so the extra current supply make no difference. Well, that the best theory I have anyway.
    The big question is, does it worth getting the iUSB Power? As I have said before, I would have been very happy with just the iDAC alone. The improvement from iUSB Power is noticeable, but not quite the doubling of total price. If you are looking for the best bang for the buck, I would think iDAC alone is more than suffice. iUSB Power is the option for those who really want the best of the best at any cost. Also, as I have mentioned, iUSB Power will likely to be more beneficial to those USB DAC that has a headphone amp or meant to drive headphone directly. So if you are only using iDAC as line-out (or USB DAC like UD100, which is limited to line-out only), you might not get a clear cut result.
    Triple Stack (from top): iCAN, iDAC, and iUSB Power.
    iCAN comes with two EQ: 3D Holographic Sound (3DHS) and XBass. Both have two levels of adjustments.
    The first level of 3DHS is pretty much the same as most crossfeed implementations I have heard before (HeadRoom BitHead, Meier Audio Corda 3MOVE, FiiO E12, etc), neither better nor worst. I generally don’t find crossfeed of this type to be particularly useful or enjoyable, so I usually don’t use it. The 2nd level of 3DHS on the other hand is a completely different beast. It sounds much closer to a full 3D simulation, like a cross between SRS and BBE in a very good way. It gives a very ‘surround sound’ effect without overdoing anything or making it sounds fake. It is good enough that I first thought that it must have some kind of DSP processing involved, but it is actually all analog based, which is actually quite impressive.
    XBass: light and heavy boost.
    The two levels of XBass are closer to a sub-bass boost. First level starts just under 200Hz and peaks around +7dB @ 20Hz. The 2nd level starts just under 800Hz and peaks around +9dB @ 20Hz. Both are strong at boosting sub-bass but have minimum effect over the rest of the frequency range. Overall, they perform very well.
    Both 3DHS and XBass can be engaged at the same time with different combo. They are quite fun to play with and can be very useful to some headphone. They are really icing of the cake to the already great sounding iCAN.
    Size comparison: iCAN, iDAC and iUSB Power with O2 (left), FiiO E12 (right) and FireStone Auido Fireye HD (lower right).
    …in Summery
    All and all, I am quite impressed by all three iFi ‘Micro’ gears. They perform well and priced reasonably. You can probably get an ODAC + O2 combo that is a little cheaper and offer similar sound quality, but you won’t get as much features as either iDAC or iCAN. The only thing I wish to have is a gain switch on iDAC and iCAN most because I am mainly an IEM user. Too much gain makes for much lesser control over volume. Beyond that, I have no problem recommending them. iDAC is a great option as an all-in-one solution while iCAN is an fantastic headphone amp. As for iUSB Power, it is not a ‘must have’ unless you are pushing for the last few percent of the performance, but it does its job as claimed. For a relatively fresh brand, iFi has made a good name for itself with these Micro gears and proven that it has the same audiophile blood in its veil as its higher-end sibling.
    A thank to iFi Audio for the iDAC and iCAN review unit.
    1. Deviltooth
      Thanks for this review. I particularly appreciate the information in how the iDAC functions with multiple BA iems.
      Deviltooth, Jul 30, 2013
    2. Rafik Moses
      Thanks for review, This information tempt everyone to get them.
      Rafik Moses, Apr 7, 2014