IFi nano iDSD Black Label Amp/DAC
Little big amp. by Mark Fleischmann
IF YOU’RE LOOKING FOR A USB amp/DAC to juice your headphones, you might assume that a couple hundred bucks would buy nothing more than a stick amp, one of those compact dongles that extends straight out from your computer’s USB port. We live in the golden age of the stick amp, and I’m sure not knocking ’em. But what if the same money can buy something with a little more real estate for circuitry and the always vital power supply, offering better than 96-kilohertz/ 24-bit resolution, DSD, MQA, and two headphone outputs with different gains, one for demanding ’phones and one for more efficient ones (including in-ear monitors, aka IEMs)? Of course, you must read on.
Things from England
British parent company Abbingdon Music Research markets a full range of pricey, bleeding-edge twochannel products, including a triode vacuum tube amplifier and a CD player. In 2012, AMR launched iFi Audio as a “trickle down” value brand with high environmentalist aspirations, using materials that are either recycled (plastic) or recyclable (aluminum). Some of iFi’s dozens of products are exotic, like the LS3.5, a reimagining of the classic BBC LS3/5A monitor with a bamboo enclosure, or the Pro iESL, a headphone amp specifically designed for electrostatics. The nano line alone includes the nano iGalvanic3.0 USB isolation device, the nano iUSB3.0 USB power supply and signal regenerator, and several DACs: the nano iOne DAC, the nano iDSD LE headphone amp/DAC, and, reviewed here, the nano iDSD Black Label amp/DAC. That’s a mouthful; let’s just call it the Black Label.
The company emphasizes that the Black Label’s headphone amp outputs 10 times more power than one in a typical smartphone or tablet, enabling it to run more demanding headphones with more headroom. But its design is smarter than your average headphone amp. It provides two different headphone minijacks, one of which is designed specifically with reduced output for in-ear monitors and more efficient headphones; the other supplies full power for less efficient ’phones. AMR touts compatibility through both outputs with headphones that offer a 3.5mm TRRS balanced cable (the four-pole variety) by maintaining the balanced wiring all the way up to the amplifier, which is claimed to maintain the benefits of balanced wiring despite this being a single-ended amp. There’s also a fixed-level analog line output to feed an audio system (but no input for analog line-level sources).
Along with handling PCM files (up to 384-kHz/32-bit in various formats), the most prevalent type, the Black Label decodes exotic file types such as DSD (up to quad rate of
11.2 megahertz, also called DSD256) and DXD (a PCM-derived format used in DSD mixing, up to 384/24). It also supports the format-agnostic MQA (Master Quality Authenticated), which allows a lossy version of hires audio to travel in streams and files that are compatible with, and the size of, uncompressed 48/24 PCM audio.
The physical form of the Black Label is a modest black box about an inch tall, small enough to attach to your smartphone with the supplied rubber straps. It also has rubber feet to grip the surface of a desk. On the front are a volume knob, a multicolored LED for power and samplingrate status, and the two headphone outputs. The amp circuitry is Class AB. There is no DSP in the signal chain to modify the music. The Black Label aspires to be bit-perfect—lossy formats notwithstanding, of course.
With PCM material, the Measure mode employs a linear phase filter for flattest frequency response, and the Listen mode uses a minimum phase filter to avoid pre-ringing on transients. With DSD, Measure is narrow bandwidth, optimized for low outof-band noise, while Listen is extended bandwidth, again optimized for impulse response. I found the difference between the two modes almost vanishingly subtle on program material. The option isn’t available in MQA, which uses a predefined, mandatory fixed filter, or in DXD, which uses a fixed filter for what they call “bit-perfect” processing.
The only audio input is an unusual socketed USB-A male connector recessed into the chassis. It can charge the internal battery by drawing power from your PC (though you might instead use a common 5-volt phone charger). The company provides three accessories that plug into it: a 40-inch USB-A female to USB-A male cable, a 7-inch USB-A female to USB-B female dongle, and a USB-A female to USB-B female adapter. The company recommends them over ordinary charging cables. For use with mobile devices, you’ll have to add your own Android OTG or Apple camera adapter dongle. The Black Label can be powered via USB from Android devices, but not from iOS handhelds, which do not allow USB power draw by Apple mandate. Running it off its charged internal battery is recommended with mobile devices.
The unit is specified to run up to 10 hours on battery power with IEMs or efficient headphones. With two sets of moderately efficient cans and one set of inefficient ones—the first three mentioned below, and connected one at a time—it ran my 57-minute playlist nearly three times, or fewer than three hours, before the red battery-discharged indicator went on. iFi clarified that their initial production had firmware that set the battery warning LED too conservatively and that the unit runs about twice the time indicated by the light. I verified that the Black Label did last a more reasonable five to six hours on a full charge irrespective of the LED. Current production has the updated firmware in place, and any customer in the field who encounters this and wishes to correct it can send their unit to iFi’s service center for a software update (http://support,ifiaudio.com). In any event, the issue is cosmetic and has no effect on the unit’s performance.
As noted, I auditioned the Black Label with a couple of different HiFiMan planar magnetic open-back headphone models: the big Edition X V2 ($1,299), on which I’ve come to depend, and (just for fun) the slightly smaller (and far more affordable) HE400S
($299). Also in rotation were
the Austrian-made AKG K240 (semi-open back, about $70 online), the Sennheiser HD 600 (open back, about $285 online), and the Sony MDR-V6 (closed back, about $90 online). The HiFiMen and Sony were fairly efficient, the AKG and Sennheiser less so.
The demo playlist was David Chesky’s Venetian Concerto No. 3, first movement, with the composer conducting the Orchestra of the
21st Century (AIFF 48/24), Bernard Herrmann’s North by Northwest score, main title, with Laurie Johnson conducting the London Studio Symphony Orchestra (ALAC 44.1/16), David Chesky’s “Ben’s Farm in Vermont” from Dr. Chesky’s Ultimate Headphone Demonstration Disc (FLAC 192/24), Bach’s Goldberg Variations, first variation, with pianist Kimiko Ishizaka (FLAC 96/24), Richard Thompson’s “They Tore the Hippodrome Down” from Acoustic Rarities (FLAC 88.2/24), Nick Drake’s “Hazey Jane II” from Bryter Layter (FLAC 96/24), Steely Dan’s “The Caves of Altamira” from The Royal Scam (ALAC 44.1/16), King Crimson’s “Meltdown” from Radical Action to Unseat the Hold of Monkey Mind (ALAC 44.1/16), and for a grand finale, Pink Floyd’s “Echoes” from Meddle (ALAC 44.1/16).
With Planar Magnetic Headphones
The Black Label performed brilliantly for a $199 amp/DAC, allowing nearly every headphone to fulfill most of its potential. As promised, it delivered enough juice to power even the most demanding of my headphones, with a little (or a lot of) room to spare. The IEM mode delivered less gain, allowing a wider range of volume adjustments for the more efficient ’phones. Tonal balance was on the light side, illuminating the presence region beautifully, while artfully dodging listening fatigue with most of the cans and content. Bass was usually sufficient but not outstanding. It was obvious that the Black Label’s heart was in its reproduction of vocals and instruments occupying roughly the same spectrum.
With the two HiFiMan planar headphones, the Black Label produced a suitably large and deep soundstage with a perspective that was up close but not uncomfortable, and it demonstrated loads of pleasurable tone color. Imaging was just how I like it: well outlined but fully fleshed out.
Among the three orchestral test tracks, the star was the Varèse Sarabande release of North by Northwest. As my notes remind me, it literally made me say “wow” to an empty room. The top end’s rippling castanets were zingy and vibrant without being overwhelming. The recording is loaded with reverb and ambience, giving the orchestra an exotic undulating quality, and as reproduced here the long decays were rigorously structured and coherent. The spatial coherence also suited the massed strings and solo flute of the Venetian Concerto and the piano of the Goldberg Variations. With my go-to track for highfrequency finery, “Ben’s Farm in Vermont,” the Black Label excelled with every headphone; I never had to turn it up but could still hear all the delicate instruments at the low levels allowed by the recording.
The two folkie tracks showed how beautifully the Black Label could handle voices. It gave the Richard Thompson home-studio recording a full-bodied richness in both voice and acoustic guitar, a quality that would be elusive with the headphone output of an average smartphone or tablet. The gorgeously produced and engineered Nick Drake track was remarkable not only for vocal realism and balance but also for layering of complex arrangements. Steely Dan’s vocals, backing vocals, and horn charts also benefited from adroit layering, as did the numerous keening, chugging guitars overdubbed onto the Pink Floyd epic. The HiFiMan HE400S had a slightly darker tonal balance than the Edition X V2, which worked well on the King Crimson track, moderating the sax’s bright bite and giving the three clockwork drummers an attractive patina of grunge.
With Dynamic Headphones
When I moved from planar magnetic to the more commonly found dynamic headphones, the Black Label scored two out of three, enabling the AKG to conjure smaller but tighter images than the planars and conspiring with the Sennheiser’s peerless sense of flow.
And it handled the headphones’ challenging nominal impedances of 600 and 300 ohms, respectively, generally using half to two-thirds of the volume control’s range when connected to the higher-output jack. Only with the trebly Sony did the Black Label’s light tonal balance become too much of a good thing—though when I re-auditioned the Sony later, at the start of another day, I realized that much of my dissatisfaction was in direct comparison with the other headphones. With fresh ears, the Sony/iFi pairing wasn’t half bad.
With the orchestral and piano selections, the Black Label appropriately did little to offset the AKG’s darker tone, though this pairing still showed excellent detail retrieval on the chiming instruments of “Ben’s Farm,” and its imaging of the Bach piano track was the most straightforward and realistic of the lot. Lead vocals on all tracks that had them were similarly shifted to the dark side. The AKG/iFi combo got the meatiest groove out of Steely Dan and the best live feel out of King Crimson. This led me to veer from my playlist and put on Led Zeppelin’s “Black Dog” which erupted like Old Faithful; the urge to play it loud was irresistible and, thanks to the amp’s output capability, quite feasible. But, returning to the playlist, the AKG sucked the life out of Pink Floyd, turning vocals bland and guitars muddy. These ’phones also pinched my noggin painfully, reminding me why I rarely use them nowadays.
Putting on the plushly padded Sennheiser was a physical relief. Although they usually produce little low bass, their winning way with midrange not only flattered the strings of the Venetian Concerto but also gave them an irresistible sense of forward motion. In the giddy tarantella of North by Northwest, the Sennheiser/iFi team was dark like the AKG but close-up and vivid like the HiFiMan Edition X V2. “Ben’s Farm” lost some of its fleecy finery to the Sennheiser’s reserved top end, but the Bach piano track was pleasingly warm, with a medium perspective, neither in the piano nor too far from it. The word natural appeared in my notes on the Thompson and Drake tracks, with the latter inspiring a torrent of additional adjectives:
“dark, warm, smooth, flowing, each element in its place.” The Sennheiser/iFi team reveled in the lead vocals of Steely Dan but lost the lushness of the backing vocals; I blamed the headphones, not the amp. Toppy elements like King Crimson’s sax and Pink Floyd’s screaming-seagull slide-guitar effects were discreetly smoothed out—again, not unexpectedly, with these headphones.
The Black Label allowed most of the headphones to be the best versions of themselves most of the time. But with the Sony, it spotlighted a top end that is already prominent and clinical with most amps, leading to lower volume settings, drier textures, and miniaturized images. Even so, in one instance, the Sony/ iFi combo succeeded where the Sennheiser/iFi combo failed, illuminating Pink Floyd’s airy vocals and complex thicket of guitars, even if the seagull effects were predictably searing.
For the price of a stick amp, iFi’s nano iDSD Black Label musters features and output capability you won’t get in most stick amps, yet it still fits in a pocket. It is ingenious, great sounding, and highly recommended.
Audio Editor Mark Fleischmann is the author of Practical Home Theater: A Guide to Video and Audio Systems, now available in both print and Kindle editions.
The front panel offers a pair of headphone outputs, each with a different gain.
The compact nano iDSD measures 2.5 by 1 by 3.8 inches and weighs in at 5 ounces.
The simple back panel includes a line out, USB port, and filter switch.