[Review] iFi-audio iDAC - USB DAC and headphone amp

iFi-audio iDAC 24bit/192kHz HD USB DAC

Just another USB DAC or something monumental?

Product name: iFi-audio iDAC
Manufacturer: iFi-audio - UK (subsidiary of AMR) with distribution companies in other countries.
Cost: 275 UKP. (Currency conversion)
(YMMV)

Reviewer: Nick Whetstone - TNT UK
Reviewed: May, 2013

The one area of hi-fi that really seems to be significantly moving forward is computer audio. Love it or hate it, we're seeing as many new products like USB DAC's and converters as speakers or turntables. At least that's how it appears from what I am being offered for review. I've recently reviewed a number of these items, and it looks as though I've got a few more to audition. The asynchronous iDAC from iFi-audio is the latest, and to be honest we could start wondering if these USB DAC's aren't what we call in England 'much of a muchness' i.e. all fairly similar.

The iDAC reminded me of the Devilsound USB DAC in that both utilise power from the host computer rather than using a separate PSU. Now I once thought that this was a sure-fire recipe for compromised sound quality but my experience with the Devilsound DAC left me far less sceptical after I actually heard it. The iDAC is larger than the Devilsound DAC but still fairly compact in terms of hi-fi equipment. It's very lightweight as it doesn't require a transformer. With a USB socket on one end, and output phono (RCA) sockets on the other, the only other point of interest is the headphone output socket and the headphone volume control knob. Yes, the iDAC is a headphone amplifier as well as USB DAC! Oh, and I nearly forgot, there are three tiny lights to indicate when the iDAC is powered up, when a signal is locked and when music is playing.

Inside, the iDAC boasts an ESS Sabre DAC chip, used according to iFi-audio because " the ESS Sabre chip’s advanced Hyperstream technology provides up to 10x better signal-to-noise ratio, superior dynamic range, and unrivalled jitter rejection making it audibly superior to the competition." The 'dirty' 5 volt supply from the host computer is converted into three separate supplies, and the iDAC also boasts an output stage which is directly driven from the DAC that not only does away with coupling capacitors but allows a greater output swing than commonly achievable with a single 5V supply.

The iDAC requires a driver to be loaded before it is ready to use. My first attempt to load the driver for the iDAC on a PC running Windows XP was a somewhat frustrating experience. When I connected the iDAC the computer asked me to connect it. This went on for a while until I restarted the PC, restarted loading the driver, and then all went well. I should add that later I downloaded and installed a later version (6.1) of the driver onto a laptop running Windows 8, and the whole process went through without a hitch. You can use the latest driver for Windows XP, Vista, 7, and 8. No driver is required for Linux based, or MAC operating systems.

The iDAC connects to the host computer via a short USB 2.0 cable that is supplied with it. If you have read my other reviews you will know that I prefer this method to connecting a USB device directly to the computer and thus to its mechanical vibrations. With the driver already installed, I only needed to start Foobar2000, select the iDAC as my output device, select a track, and start to play music.

I have got into the habit of keeping a selection of my favourite reviewing tracks on a USB stick that I can move from system to system. I began by playing some tracks from that but was left rather unimpressed. In fact I would go far to say that I felt that there was something actually wrong with the sound. I checked the whole system from iDAC to speakers but could find nothing amiss so I left the iDAC playing for a few hours and came back later. It still didn't sound right to my ears and I was actually wondering about contacting iFi-audio and asking if I possibly had a faulty item. Instead, I left the iDAC playing for another 24 hours and when I returned the next day, it sounded better but still not what I was expecting. To cut a long story short, the iDAC probably required the longest burn-in of anything that I've reviewed, but also exhibited the greatest improvement in sound quality as time went on.

[iFi-audio iDAC headphone control and RCA's]

Eventually I heard what the iDAC is really capable of, and the wait was worthwhile. The level of detail that the iDAC produces is as good as anything that I've heard to date. I think that it confirms how far we are moving forward with hi-fi sources, and I doubt if any but the most expensive CD players can now compete with something like the iDAC, at least in the level of detail that it retrieves. It is certainly no shrinking violet and everything comes through loud and clear, but that's not so say that it isn't subtle as well. Nuances in singers' voices, the clearly audible differences between instruments in an orchestra, the tiniest details like a triangle in a full orchestral symphony, drum hits on different parts of the drum kit, and of course the Q-sound effects on something like 'Amused to Death' (Roger Walters) were all portrayed with great clarity. The clarity of vocals is so pronounced that on a good recording the artist appears almost holographically in the room. The vocals of artists like Katy Meluha and Amy Winehouse are also very intimate with the illusion that they are there in the room. Not surprisingly this all makes for a high degree of realism. In fact it can be very real! You really can close your eyes and imagine the music being performed in front of you.

The tight control extends to the bass that I found was very prominent (but not in an over-powering way) and very well controlled. Tracks (Dreadzone, Faithless etc) that had (with other equipment) produced some bloom in my small auditioning room didn't with the iDAC. Bass was also fast and tunefull.

The clarity made for excellent imaging. I'm not really one to take note of claims made by manufacturers and advertisers but the picture on the iFi-audio site is quite accurate in how it portrays the iDAC's imaging.

[Representation of imaging quality using an iFi-audio iDAC]

The sound stage was large, both wide and deep but I did observe (or should I say hear) something interesting. The sound stage was slightly deeper with the earlier version of the driver, and the Q-sound effects came out further forward from the speakers. But.... I found the later driver produced a sound that was more involving, ie more emotional than the early driver. Both drivers produced excellent PRaT, and my favourite track for that test, Paul Simon's 'Graceland', that sounded as good as I have ever heard it. Notes started and stopped as they did when the music was created, leading edges were crisp making each note audible against the others, and the gaps in the music were there with a black ground, rather than the overhang or what preceded them. In short, the iDAC played music with a vice-like control that added to overall reality of the performance. Scale was very good too, with instruments and performers sounding life-sized depending on the quality of the recording.

The iDAC is a high definition device and I played several 24/192 tracks through it without any problem, while enjoying the clearly increased detail and control that those recordings can produce on the right equipment. It's when playing such recordings that I realise that we have well and truly left the CD player behind with its 16/44 playback limitation. No matter how good an item is, the ultimate test is does it sound enjoyable to listen to? Well if I tell you that my upstairs auditioning room is unheated, and that for some of my sessions, I was sitting in a room at 10-12 degrees centigrade, and still couldn't drag myself away from listening to the iDAC, that should give you a good idea of how much I enjoyed it. Even with my cheapo headphones I was able to enjoy the iDAC as a headphone amplifier but I'll be honest and say that I enjoyed it more through an amplifier and speakers. No doubt a set of much better headphones would change that. I hardly need add that the iDAC sounds much more analogue than digital.

Being an incurable DIYer and tweaker, I couldn't help wondering what the iDAC would sound like with a better power supply. So out came the Elijah Audio cable that I used with the HiFace Two, and I tried several external power sources including the excellent Paul Hynes SR1-5, one of my own 5 volt linear supplies, and a battery supply. But while I had found these to make a discernable improvement with the HiFace Two, there was little or no difference with the iDAC. That's surely a testament to the quality of the supply inside it, and no doubt part of the explanation as to why it sounds so good.

Another aspect that I noticed between the iDAC and other USB DAC's that I have auditioned was that the difference between using say Foobar2000 on its own as the playback software, and using it with the JPLAY plug-in was less than I experienced with other USB DAC's. I'm not sure why this should have been other than that the iDAC is so good that it sounds phenomenal without JPLAY. JPLAY of course adds to the cost of a computer playback system so if there is less reason to purchase it, it makes the USB DAC better value for money. That said, there was still a slight, but clear improvement when using JPLAY.

I also tried the iDAC connected to a PC running Ubuntu with QMMP for the playback software. QMMP is said to be bit perfect. I started the PC up with the iDAC attached and it wasn't recognised, but it only required unplugging and plugging it in again and it was ready to play music. You may have to select the output device as iDAC in the Sounds section of Ubuntu configuration. The results were very pleasing. Once again I had intended simply to connect the iDAC up and confirm that it played music through a Linux-based system, but over two hours later I still found myself trying track after track. I would say that Windows 8/Foobar/JPLAY wins for all out detail and clarity, but the Ubuntu set-up sounded no less enthralling. My Ubuntu PC was being thrown away by a friend and cost me nothing; Ubuntu and QMMP are freeware, so this set-up with the bargain-priced iDAC makes for a budget source that will truly compete with something costing many times more.

Those of you of a similar age to myself will remember the debate about whether we should spend the bulk of a hi-fi budget on the source, or the amplifier and speakers, or spread it evenly between them. In those days it was a valid argument because a top-end source didn't come cheaply. With the arrival of the USB DAC (particularly these high definition models), the cost of a really good source has been reduced dramatically, and at its price, the iDAC offers remarkable 'sound per pound' value. I believe that we can now put a hi-fi system together that would compete with (or even better) a top-end system from the 1960's or 70's but at a fraction of the cost.

Summing up the iDAC, I can't find a bad word to say about it. At one stage I thought that I noticed sibilance on one or two tracks but after some investigation, I believe that this was in the recordings, and emphasised by the iDAC. It is of course one of the negatives of such a revealing source that it will emphasise the poorer parts of a recording. I also found that being so lightweight, the iDAC benefited from my DD tripod set up, together with a few chunks of granite to weigh it down and add some mass. It's one of those items that is so light that the interconnects can easily pull it over. I found that it easily played into all the amplifiers that I tried with it, and didn't appear to need another active stage between it and the power amplifier. The price of the iDAC (judging by what it is being sold for here in the UK) is very competitive, both against other USB DACs (none of the others that I've reviewed match the degree of realism), and CD players (limited to 16/44 playback). Not so many years back 275 pounds would have bought little more than a mid-range CD player, and the sound quality of the iDAC is a quantum leap ahead of one of those, although it should be remembered that you require a computer source as well as the iDAC. But without reservation, I have no hesitation in heartily recommending the iDAC. It will almost certainly show many people how much information there is in recordings that they haven't heard before, certainly from a digital source!