October 2015

iFi Audio iDAC2 Digital To Analog Converter With Headphone And Line Output
An incredible sounding DAC for only $349.
Review By Steven R. Rochlin

  Am no stranger to iFi Audio as have reviewed their Micro iDSD unit in September of 2014 and this review of the iFi Audio iDSD2 ($349) showcases the company's continued ability to employ the most modern chipsets of the day mated with their critically-acclaimed high quality headphone amplification. iFi Audio's new iDAC2 is a complete rethinking and redesign of their previous iDAC. Burr-Brown has been heralded as one of, if not the, top chipset and within the iDAC2 it provides True Native playback on DSD and PCM. What this means is that there is no re-sampling or converting of the digital audio file as it leaves the signal unchanged all the way through. Therefore DSD does not turn into PCM as found within other devices, even those by DSD's inventor Sony(!).

iFi Audio's iDAC2 handles everything up to DSD256 and PCM up to 384kHz via USB input. There is a standard S/PDIF digital input that handles PCM up to 192kHz. Analog output is both stereo 2.1V RCA and 3.5mm headphone jack with 350mW (2.4V @ 16 Ohms). There is a volume control that works quite well, yet with some of my higher sensitivity CIEMs I do wish there was a way to adjust the output via a switch, as found on the Micro iDSD, to take better advantage of the volume control. With the CIEMs I find myself using very little of the volume adjuster's capability, yet with normal headphones this is not an issue. iFi Audio's iDAC2 has plenty of output to drive nearly every headphone. Of course the quality of amplifier is key, and so iFi Audio chooses the highly regarded Class A type within the line output to deliver the goods. Since this is not a portable device, which many need the battery saving Class D amplification, iFi Audio takes advantage of the power within your computer's USB jack to provide endless hours of amplification. The iDAC2's analog stage has two Elna Japan Silmic II special audio grade electrolytic capacitors. According to iFi Audio, these are the very best money can buy and are also found within the über AMR DAC machines. The company's discrete Class A buffer combines an N-Channel J-FET and a PNP bi-polar transistor to handle even though tough 600 Ohms headphones.

iFi Audio's iDAC can also take your computer's USB digital audio output and convert it to S/PDIF RCA output to feed whatever DAC you choose. Then again with such an excellent internal DAC within this unit, am curious why someone would do such a thing, unless of course you've got an AMR or other mega-precise (and priced) DAC. iFi Audio does wisely say that you can also use the iDAC2 to feed a Sonos digital input, so perhaps they have a good point for providing S/PDIF output as do have a Sonos system here as do many of our readers.

When it comes to your computer's USB output, there is abundance of tweaks including power filtering and whatnot such as iFi Audio's iPurifier, which is being used within this review. The iPurifier has iFi Audio's PurePurification technology that is said to remove unwanted EMI from USB, removes DC offset and rebalances the USB audio for top-notch digital signal transmission. While I'm not looking to review the iPurifier separately here, I will say it does make a difference in helping the iDAC2 achieve this level of smoothness and clarity as reviewed here. It seems to give you that last bit of clean resolution and a small bit of better, smoother microdynamics. Call it adding that last bit of refinement to an already impressive for the money sound. By the way, the iDAC2's power supply includes a 'Super Regulator', which is a shunt noise filter to clean the USB power for the DAC. High-grade Japanese Panasonic film capacitors are surface mounted to smooth out and provide a clean and steady electrical source. Feel the need to say you don't need to use the iPurifier, yet for those seeking the last tiny bit of audiogasm it is well worth the $99.

My listening notes thus include the iPurifier and for the iDAC2 it has the 5.0 Vanilla firmware that features a variety of code optimizations. As this is the latest and greatest firmware from iFi Audio, it also ensures what I'm hearing is currently the best they offer. Both computer geeks and tweaky audiophiles know that drivers and firmware can make a difference in how a product sounds. Am using my top-line 15” MacBook Pro with SSD and all the memory they can squeeze into it from the factory. When it comes to computer hardware I don't mess around. CIEMs used are the Noble K10, 64 Audio (was 1964 Ears) A12 and JH Audio Roxanne CIEMs plus the OPPO PM-3 headphones. Of all the combinations, the 64 Audio A12 were the most synergistic, with the JH Audio Roxanne and Noble K-10 coming a tie for second yet for different reasons (Roxanne for authoritative sound and K-10 for overall musical neutrality).

A Sound That Draws You In
After the recent flurry of portable audio player reviews by Yours Truly, it was nice to step back a bit from the limitations of such devices. Headphone amplifier tricks such as Class D and ways to cut corners to optimize power consumption are not as much an issue with USB DACs. Of course you then enter the next level with price-no-object home audio DACs, yet at some point there is a diminishing return factor. When it comes to power, electronics love clean juice and as much of it spread to every circuit so that each one can operate optimally. By using pure Class A amplification within the line output, the iFi Audio iDAC would probably drain your typical portable audio device in a matter of an hour, if not a matter of minutes! Sure it 'wastes' power and generally generates more heat than other amplifier designs, yet like a car engine the more grunt and power you want to have the more heat you'll develop. The headphone amplifier may not be 100% pure Class A, yet it sounds outstanding in its own right! When listening to the iFi Audio iDAC2 my ears instantly 'recalibrate' to how incredibly well music can sound when certain limitations are not present. Then again it could simply be that the iFi Audio iDAC2 sounds far more refined than many portable audio units that am throwing the proverbial dart at the board on what is to blame for the mesmerizing sound I hear with the iDAC2 versus portable audio devices (save perhaps the Sony NW-ZX2, which I'll get deeper into this later).

Stereo separation and dynamics are gloriously gushed forth with the iDAC2. Nothing feels forced or restricted. There is a natural ebb and flow to the music. While this might not at first demand to instantly grab your attention, which is akin (visually) to a video screen with higher-than-reality color saturation. It is when things are naturally presented over a period of time that they become more obvious in their accurate refinement. For me, it is a parallel to fine art that with the proper lighting has the ability to draw you into the painter's vision. Too much light and things are washed out, and with too little light you miss the shading subtleties. I find it interesting that some audio manufacturers choose their own color pallet, which is pleasing to some yet perhaps not with others. iFi Audio decided upon a more natural, refined sound over audio pyrotechnics. Album after album I find myself more relaxed within the music and drawn in versus being drawn to the music. Of course this sounds all well and good from an ethereal writing standpoint, but what are the specific details without all this reviewer mumbo-jumbo 'nonsense'?

Starting at the bottom up, bass is quite deep and good. Not the very last word in drive or immediacy, yet at this price level it was impressive. It was more of a flow than a jump with modern dance and techno. My spider sense tells me you'll be seeing the word 'flow' more and more within this review. PRAT (pace, rhythm and timing) were very neutral to perhaps the more relaxed side of intensity. Lower bass and midrange fall into the same category and if you love mellow jazz, classical music and typical audiophile female singer styled music the iFi Audio iDAC2 delivers that desire-n-devour-me-gently sound. It is the sound of suppleness that has you exploring all the gentle curves and dramatically rounded points as you explore the innermost nature of the music versus trying to take it all in at an instant. iFi Audio's iDAC2 had me tenderly examining the finer points within the music.

The uppermost frequencies are very extended without ever becoming overtly aggressive, unless the music strives to be outright so (I'm looking at you 1990's grunge). There is a surprising amount of clarity with the iDAC2 that belies its price, yet is not on par with cost-no-object reference DACs. It is the omission versus commission, which I personally prefer. Well done iFi Audio! It also makes me yearn for a higher budget and more flexibility like the $499 micro iDSD and home DACs. I just know there is more there, yet my ears are being teased with the iDAC2... and they want more. When it comes to revisiting the imaging and soundscape, the iDAC2 gives you almost reference level separation and image width / positioning. From tightly center to backup singer pairs off-center and expansive hall sound, the iDAC2 delivers it far beyond what I felt was possible at this price level. There is a natural spaciousness to the sound that flows naturally when this type of sound is within the recording.

Note: iFi Audio's iDAC2 is not available in blue. We're having some fun in Photoshop.

Ok, so you're wondering is the iDAC2 with iPurifier better than the micro iDSD. It is about the same price and all that. Well, the iDAC2 is smoother, has a touch more resolution and is a shade more refined. Would have loved to try the iPurifier with the micro iDSD yet don't have that unique cable adapter combo here. Oh, wait, I do! Reaching into my two draws literally filled to the brim with cables and adapters I did a head-to-head of the iFi micro iDSD as compared to the iDAC2 and the iDAC2 has a touch more resolution and overall smoothness. It is not a huge difference, and thus quite subtle in some respects yet it is there.

Smackin' That DAC
For $349 there's a lot to love about the iFi Audio iDAC2 with the $99 iPurifier. Those who cherish jazz, classical and relaxing music can plunge pleasantly into the music. I find myself time and again reaching into the sound and always wanting to hear more hour after hour. It is like being teased time and again as mega-buck home audio DACs, such as those by AMR, deliver more. It produces a delightful sound that is far more than just dipping your toes into the proverbial waters. You get knee-deep in this refreshing sound as it handles every file type from lossy MP3 to the latest DSD and 384kHz music files. One does not expect reference-level at this entry-price, yet you want those compromises a manufacturer makes to benefit the music. Here is where iFi Audio succeeds and you need not worry about future formats as they are great with firmware updates and it already handles every format I can throw at today (and I can throw down some crazy-mad file formats). There is plenty of headphone amplification for efficient in-ear monitors to virtually every headphone. My only caveat is that using highly sensitivity IEMs means you'll be using only a small fraction of the volume knob's output level. If you're curious what all the hi-fi and music enthusiasts are going on about with Hi-Res Audio, then the iFi Audio iDAC could be just what you're looking, and listening, for! As always, in the end what really matters is that you...

Specifications
Type: Digital to analog converter (DAC) with line out and headphone amplifier
Input: USB3.0 (USB2.0 compatible) 
Digital Output: S/PDIF RCA (only PCM up to 192kHz) 
Analog Output: Stereo RCA 2.1V fixed line output and 3.5mm stereo headphone 

Line Output: Zout < 39 Ohm
SNR: > 114dB(A) @ 0dBFS 
THD+N: < 0.0025% @ 0dBFS (100k load) and < 0.025% @ 0dBFS (600R load)

Headphone Section: Output: > 350mW (2.40V) into 16R (<10% THD+N) 
> 34mW (3.20V) into 300R (< 0.1% THD+N) 
Zout: < 2 Ohm 
THD+N: < 0.0025% (1V into 16 Ohm, 0dBFS) 
SNR: > 114dBA (3.2V into 16 Ohm, 0dBFS)

Formats: Up to 384kHz PCM, 12.4MHz DSD, and 384 KHz DXD
DAC: Bit-Perfect DSD and DXD DAC by Burr Brown (one DAC chip; stereo, four signals) 
Filters: 
  PCM: Bit-Perfect/Minimum Phase/Standard, Digital filters selectable 
  DSD: Extreme/Extended/Standard, Analogue filters selectable 
  DXD: Bit-Perfect Processing, Fixed Analogue filter 
Dimensions: 158 x 68 x 28 (LxWxD in mm)
Weight: 0.58 lbs. 
Price: $349, with the iPurifier being $99

Company Information
ifi Audio 
E-mail: contact@ifi-audio.com
Website: www.iFi-Audio.com