iFi nano iDSD DAC/Headphone Amp
Input: Async USB 2.0
Output: Coax S/PDIF, 1x pair RCA analog, 1x 3.5mm headphone out (output impedance: 1 Ohm)
Dimensions (L x W x H): 87 x 68 x 28mm
Availability: Online and through Authorized Dealers
The iFi nano iDSD DAC also doubles as a battery-powered 80mW headphone amp and can handle PCM resolutions up 32/384, DXD, single and double rate DSD and with a recent firmware upgrade even quad rate DSD. Unlike the recently reviewed Geek Out DAC (see review) and some of the other micro DACS, the iDSD is not a micro DAC per se coming in about the size of a pack of Camels. The cigarettes, not camels. Also like the Geek, there's a physical volume control but here its handled in the analog domain, USB in, and because of its bigger body its able to accommodate a pair of RCA outputs instead of the 3.5mm minijack found on the Geek Out. iFi also throws in a Coax output and two filter choices; minimum phase recommended for listening and "standard" recommended for measurement.
The iDSD DAC uses a Burr Brown DAC which handles PCM and DSD close to their own terms. According to the designer Thorsten Loesch from our Q&A (recommended reading):
...DSD remains DSD and is converted directly to analogue. PCM remains PCM and is converted directly to analogue.
In the iDSD nano (and the whole upcoming iDSD range) we go to great length to provide that. Finding a readily available DAC chip that treats both DSD and PCM fairly was a challenge. Manufacturers generally are quite mum about what goes on inside their chipsets, so often you have to actually test the part in detail to figure out what is really going on.
The DAC chip we use in the iDSD nano offers a rather unusual way to handle things. It uses a 6-bit true Multi-bit DAC for the upper 6-bits of PCM Audio and delivers the warmth and slam Burr Brown Multi-bit DAC’s are so famous for. Any bits below this are converted with a low order 256 speed Delta Sigma modulator (in effect DSD256), giving PCM playback the smoothness Delta Sigma DAC’s and DSD are famed for.
When playing DSD the same Delta Sigma Modulator is used as directly to convert the DSD bitstream to analog. Of course, there is no digital filtering available for DSD and no digital volume control, so we have to add these features in the analogue domain, where they arguably should belong.
The iDSD's USB input comes courtesy of XMOS and is of the asynchronous variety and the headphone amp's output impedance is rated at a low 1 ohm by iFi. On one end of the unit resides the USB input, Coax output, and filter option switch. On the opposite end you'll find the RCA outputs, 3.5mm headphone jack, and the volume/on/off control knob. iFi claims 10 hours of playback time for the battery-powered headphone amp. Lastly there's a multi-colored LED up top which indicates the sample rate of the file being played, USB connection status, low battery, empty battery, and charging.
The battery power and charging is handled in an interesting way in the iDSD so I asked iFi to explain:
In USB power mode the iDSD nano will draw power from the USB Port to both operate and charge the battery. If the USB Port is on an iPhone or aPhone doing this will either result in error messages or in a quickly drained battery.The whole affair is wrapped in silver aluminum and the feature set and build quality belies its $189 price tag. iFI also provides everything you need to get going including a USB cable, RCAs, and a small travel pouch. Nice. But all of that doesn't add up to a hill of beans if the iFi iDSD DAC doesn't make music worth listening to. Luckily for us lascivious music listeners and lovers, it sure does.
So actually specifically for these devices the battery mode exists. In this case the current drawn from the USB port is close to zero (just enough to detect the Host a few micro ampere), so all power to operate is drawn only from the battery.
A separate area is how the DAC Chip and Analogue Stages operate. They run directly from the Battery at all time.
But in USB powered mode the Battery they draw power from will be "charged" from the USB Power at all time. Of course, the charge current will only be the operation current of the device once the battery is charged up to full. One might call this operation "Battery Buffered".
Battery Mode can of course also be used with Computers etc. Once the Battery is flat, the iDSD nano will automatically restart in USB power mode and charge the battery and continue in USB power mode, so as long as the PC is switched on or in one of the suspend/sleep modes that maintain power on the USB Port, it is pretty much fit and forget and the battery will be maintained at optimum.
I spoke about the iDSD DAC a bit in the Geek Out 1000 review and that review is worth a read since it also includes brief comparisons to the AudioQuest Dragonfly and Meridian Explorer. I'm going to focus more on the iFi and Geek Out DACS here since they are so similar in terms of features and functions.
Pretty much from the get go, the iFi iDSD DAC announced itself with a nice, rich, round sound. It offered a lovely dimensional quality to the music it reproduced that I've come to associate with a handful of mostly more expensive DACs. The Halide DAC HD is one example (see review) but that DAC is limited to 24/96 and it does not offer a headphone amp and there's the much more costly Ayre QB9 DSD (see review) and Auralic Vega (see review) both dimensional champs, and perhaps the all-time heavy weight world champ the totaldac D1-Dual DAC (see review). While the iFi iDSD DAC does not go to their lengths, it delivers a nice healthy helping and outpaces most of the similarly priced DACs in this regard in this category including the AudioQuest Dragonfly and Meridian Explorer which is pretty remarkable considering its price.
There's also plenty of slam, weight, big fat well textured bass, and sweet highs, all areas where I find the iDSD DAC outperforms the Geek Out 1000. Tone colors are relatively rich, although not as full spectrum as more costly DACs like the Auralic Vega. But again, you're getting a nice helping from the iDSD DAC which is pretty remarkable considering its price. Where I'd give the upper hand to the Geek Out is in terms of overall resolution and a lit up quality that some may find more exciting. My personal preferences have me digging the iDSD for what I hear as a more natural and emotionally engaging sound. The presentation is wetter, deeper, and decay sounds to my ears natural and convincingly analog-like.
I mainly listened to the iFi iDSD DAC in my main system with my MacBook Pro, the Pass INT-30A, and DeVore The Nines using the Pass' volume control (the iDSD's volume was maxed). I spent some real time listening to this combo, days on end, nights one end, with all sorts of music from good old CD-quality, up to DXD, DSD and double rate DSD. To say that I was pleased as punch regardless of the file format would be an understatement. There was a consistent, rich, warm, lively, and inviting sound with the iDSD DAC that led me from album to album, as opposed to track to track, or even worse part-of-a-track to part-of-a-track. The iFi engendered the kind of listening that is driven by musical joy.
I found myself delving back into a good chunk of the Tom Waits catalog, grooving to the recently released Novos Mistérios from Ninos du Brasil, snapping my fingers to Nat King Cole in DSD, smoldering to PJ Harvey, getting lost in Chet Baker, rocking out to Led Zeppelin, spooking out to Penderecki also in DSD, freaking to Fennesz, morose-ing to Nick Cave, and many more moods and musicians. Acoustic, electric, eclectic, small scale, large scale and everything in between including solo cello, violin, and piano works up to big rousing symphonies, the iFi iDSD DAC delivered them all with gusto. Which is pretty remarkable considering its price (I know I've repeated this sentiment a number of times but its both true and to make sure the point is driven home).
Driving my Audio Technica ATH-W1000s was also a treat, the iFi's rich, full, and weighty presentation making a nice musical pairing. There's also a goodly amount of resolution with the iFi iDSD but not so much as to draw unnatural attention to itself. Since its battery-powered, you can also use the iDSD DAC with your iPad and Camera Connection Kit which I did with my 'phones for a nice potentially portable travel system. I also did not experience any unwarranted noises from the iDSD's volume control as come users have reported and found the unit to perform silently and without a hitch.
iFi Nailed It
I'd say iFi nailed this one. The iDSD offers what I hear as a more fulsome, dimensional, and all around more engaging sound as compared to many of the like-competitors on the market. For its asking price and multiples thereof, the iFi iDSD makes a no-brainer recommendation for use as a PCM, DXD, and DSD DAC. Consider the headphone amp a bonus.
Also on hand and in use during the iFi nano iDSD DAC review: LH Labs Geek Out 1000, AudioQuest Dragonfly DAC, Meridian Explorer