iFi’s diminutive and cost-effective Nano iDSD Black Label headphone amp/DAC ($199/£200) beckons with an extensive list of features and functions, but it creates an even stronger impression once listeners hear the device in action and grasp what it can really do. Conceptually, the Nano iDSD Black Label can be viewed as a ‘junior version’ of iFi’s critically acclaimed (but also significantly larger and more costly) Micro iDSD-BL amp/preamp/DAC, as reviewed in Hi-Fi+Issue 150. For obvious reasons, the Nano can not do everything its feature-packed and overachieving bigger brother can, but it does have distinctive technical tricks up its sleeve that make it quite appealing in its own right. Specifically, the Nano iDSD Black Label provides MQA support (which the Micro iDSD-Black Label does not), while also introducing iFi’s all-new dual-mono, ‘S-Balanced’ amplifier circuit topology. The point is that the petite Nano iDSD Black Label offers some compelling reasons why music lovers might want to add it to their personal audio electronics stables.
Before exploring the Nano iDSD-BL, let me supply a bit of background information for those unfamiliar with iFi Audio. iFi Audio is directly descended from the respected British high-end audio company Abbingdon Music Research and it is important to understand that in every way iFi products deliberately leverage serious audio design know-how drawn from AMR. In fact, it is no exaggeration to say that iFi products aim to deliver the essential elements of the AMR sound, but in products that are compactly sized and that sell for down-to-earth prices. Those who have heard AMR’s premium-priced full size components will know they set a very high (perhaps impossibly high?) performance target for iFi products to aim for, but we can only applaud iFi for setting its sonic sights so high.
Generally speaking, iFi offers three main families of personal audio components (Nano, Micro, and Pro-series models), the smallest and least costly of which are the Nano components, whose chassis are about the size and shape of a thick deck of playing cards. As we talk about the Nano iDSD‑BL, please bear in mind that it is an almost ideal ‘take-along’ size and compact enough to fit easily in trouser or jacket pockets, or in most any handbag.
What does the term Black Label imply? Apart from evoking positive associations with a certain well-liked brand of blended Scotch whisky, iFi uses the term “Black Label” to denote models that have been built with carefully specified sets of specially selected, sound quality-minded parts. In the case at hand this means the Nano iDSD-BL uses Tantalum polymer capacitors in its power supply, thin film resistors for its audio section, TDK C0G capacitors for its analogue filter, Panasonic ECPU film capacitors for critical DAC reference voltages, MELF resistors for its proprietary iEMatch® circuit, a precision analogue volume control potentiometer, and an aircraft-grade aluminium chassis given a distinctive satin black finish unique to the Black Label models. My point is that Black Label models use better parts and sound even better than iFi’s standard models do, which is saying a lot.
The DAC section of the Nano iDSD-BL is versatile and uses a Burr-Brown DAC, says iFi, to enable decoding “truly native DSD and PCM data streams.” Accordingly, the Black Label provides support for PCM files up to 352.8/384 kHz, for DSD files up to DSD256, for DXD files up to 352.8/384 kHz, and for MQA files. The Black Label also provides two switch-selectable filter settings, labeled Listen and Measure, whose effects are context sensitive depending on the types of files being played. For PCM files the Listen setting applies a minimum phase Bezier filter, while the Measure setting invokes a standard FIR linear phase filter. For DSD files, the Listen setting applies an “extended bandwidth, transient optimized” filter, while the Measure setting invokes a “narrow bandwidth, low output band noise optimized filter”. DXD files are automatically treated to the DAC’s “fixed bit-perfect processing”, while MQA files use built-in 88.2/96/176.4/192 kHz filters as appropriate.
One further design twist is that, when upgraded with iFi’s latest firmware, the Nano iDSD-BL automatically performs 8x upsampling on incoming PCM files, essentially treating them as high-res PCM files regardless of their original sampling rates. One result of this is that the Nano’s multi-colour front panel LED no longer performs exactly as described in the User’s Manual. With earlier iterations of firmware, the LED would change colour to denote the types and data rates of the files being played. With the latest firmware, though, the LED displays just three colours during playback: white (denoting high-res PCM or DXD files), blue-green (denoting DSD files), and magenta (denoting MQA files). One additional desirable effect of the new firmware (and of the PCM upsampling feature it ushers in) is that perceived qualitative differences between standard and higher-res PCM files are minimised to a point where they largely seem inconsequential. Importantly, iFi allows users to roll back the firmware to support MQA but skip upsampling, if they so desire.
The DAC provides an asynchronous USB input that is backed by what iFi terms a Zero Jitter® memory buffer system. The concept is for incoming digital signals to be fed to the buffer system and then separately (and precisely) re‑clocked before being passed along to the DAC device. iFi claims that jitter levels are below the levels of their own test equipment. The Nano iDSD Black Label is, of course, ideal for use when playing digital audio files from a PC (via iFi-supplied device drivers) or Mac, but with the appropriate adapter cables it is also compatible with portable devices. In fact, iFi claims one of the primary uses for the Nano is to enable streaming “Apple Music/Google Play/Spotify/Tidal/Youtube content from your phone at a whole other level of quality.”
The Nano’s amplifier section, whose maximum rated output is 285mW @ 30 Ohms, is where much of the iFi design team’s technical wizardry has been applied. First off, the Nano features a dual-mono ‘S-Balanced’ technology headphone amplifier that incorporates “3.5mm TRRS balanced wiring all the way to the amplifier.” One might infer from this that the S-Balanced amplifier uses conventional balanced circuit topology, but that isn’t the case. Instead, iFi makes the bold claim that “S-Balanced technology means that despite the amplifier being single-ended, this delivers all the benefits of balanced wiring.” (Italics are mine).
In practical terms this also means the Nano can be used either with headphones equipped with balanced signal cables (fitted with 3.5mm balanced TRRS plugs) or with traditional single-ended signal cables (fitted with 3.5mm single-ended TRS plugs). iFi claims that, “plugging in unbalanced headphones with a TRS connector instead of TRRS will cause no issues and, in fact, will still cut crosstalk by 50%, compared to using a TRS socket.” The upshot is a single-ended circuit said to deliver “all of the benefits of balanced (circuitry), with none of the drawbacks.” One final important design touch involves the fact that one of the amp’s two output jacks is equipped with proprietary iEMatch® technology, which helps reduce noise and ensures proper, transparency-enhancing impedance matching when driving high-sensitivity in-ear monitors or headphones.
The Nano iDSD Black Label is, like many iFi products, capable of being either USB or battery powered, depending upon the sequence in which it is powered up. If the DAC is switched on before the USB cable is plugged in it will operate in battery-powered mode, but if the USB cable is connected before the DAC is switched on, it will operate in USB-powered mode. The Nano features a built-in Lithium/Polymer battery that iFi states should be good for about 10 hours of continuous playing time. The Nano also features a built-in version of iFi’s iPurifier technology to “reduce USB noise and rebalance the USB signal.”
To put the Nano iDSD Black Label through its paces in my listening tests, I connected it to a Windows/jRiver Media Center-based music server loaded with a mix of standard and high-res PCM, DXD, and DSD files. To test the amp’s versatility, I used it with two sets of full-size headphones (the Audeze LCD-MX4 and the MrSpeakers AEON Open Flow) and two set of very sensitive high performance earphones (the Noble Audio Kaiser Encores and the Campfire Audio Andromedas). My thought was that in this way I could evaluate iFi’s claims that the Nano iDSD Black Label was powerful enough to drive high-quality full-size headphones effectively, yet also quiet and revealing enough to use with ultra-sensitive in-ear monitors. Finally, for comparison purposes, I also had on hand the bigger iFi Micro iDSD Black Label.
I first tried the Nano iDSD-BL with the full-size Audeze and MrSpeakers planar magnetic headphones connected to the Direct output jacks and discovered the Nano had more than enough output to drive either headphone to satisfying volume levels (or beyond). Assuming you are not trying to push extremely difficult and insensitive headphone loads, power output from the Nano should prove—to borrow the old Rolls-Royce quip—“adequate”. Side-by-side comparisons between the Nano iDSD-BL and the bigger Micro iDSD-BL revealed that the sibling products share similar, but not identical, voicing. The Micro shows its deeper power reserves by conveying a subtle yet consistent quality of dynamic swagger, plus overall voicing that is a shade darker, warmer sounding, and more full-bodied than that of the Nano. In contrast, the Nano offers a slightly more light and lithe presentation with bass extension equal to that of the Micro, but with a touch less mid-bass weight and warmth. Stated another way, the Micro offers superior dynamics, body, and bass gravitas, while the Nano’s character emphasizes agility, three-dimensionality, and excellent bass pitch definition.
Next I tried the Nano iDSD-BL with my reference Noble Audio and Campfire Audio earphones using the iEMatch® output jack and it was in this context that the Nano’s sound really came into its own. Right off the bat the Nano unlocked a sound full of engaging delicacy, finesse, and low-level resolution. Together these characteristics made for a presentation offering expansive soundstages with a terrific sense of immediacy and almost rock-solid three-dimensionality. What is more, the Nano’s rendition of dynamic envelopes—that is, everything including the initial attack, the ensuing (and ‘blooming’) sustain, and the lingering decay of individual notes—was, through my IEMs, truly exceptional. Candidly, I had never heard either IEM sound so good before, which is why I’m convinced iFi is on to something special with the combination of its S-Balanced amplifier topology and iEMatch® circuit.
It’s tempting to assume the iEMatch®jack is meant solely for use with in-ear monitors, but in fact iFi also recommends trying the jack with higher sensitivity full-size headphones. I tried this experiment with the Audeze and MrSpeakers headphones on hand and discovered that both actually sounded better through the iEMatch® jack than through the admittedly higher powered Direct jack. Granted, use of the iEMatch® jack meant that the Nano’s volume control needed to be turned up higher to get appropriate output levels with the full-size headphones, but the sonic rewards were the same special qualities of immediacy and three-dimensionality I had observed through my IEMs.
Two very different tracks that show off these qualities through IEMs and headphones are vocalist Hanne Boel’s rendition of J.J. Cale’s ‘After Midnight’ from Outtakes[WM Denmark, 16/44.1] and jazz artist Henri Texier’s ‘Vent Poussiere’ from Remparts D’argile[Label Bleu, 16/44.1]. The former is an R&B/rock standard that Boel captures with an earthy and deeply soulful flavour (aided by a locked-in and bass guitar-propelled rhythm section), while the latter is an angular and at times almost austere-sounding jazz composition featuring percussionist Tony Rabeson, saxophonist/clarinetist Sébastien Texier, and bassist Henri Texier. The common denominators between the pieces involved the highly expressive and sumptuously detailed manner in which the Nano served up the smoky inflections of Boel’s voice, the razor sharp attack and lingering decay of Rabeson’s percussion notes, the gently seductive yet melancholy voice of Sébastien Texier’s horn, and the woody inquisitiveness of Henri Texier’s bass. In short, the Nano is a device that lets you hear not only the inner structure of the sounds being reproduced, but also the emotional content behind them.
iFi’s Nano iDSD Black Label is a brilliant headphone amp/DAC that offers serious sound quality in a very compact and affordable package – similarly priced rivals have far less functionality making it excellent value, too. It is a worthy little brother to iFi’s also excellent Micro iDSD Black Label, but one whose distinctive S-Balanced amplifier and iEMatch® circuitry give it a sonic appeal all its own. Go hear one, soon.
- Type: Battery/USB-powered headphone amplifier and high-res DAC.
- Inputs: USB-2.0 ‘OTG’ port with built-in iFi iPurifier technology.
- Outputs: Front panel:Two 3.5mm headphone jacks (compatible with 3.5mm TRS single-ended and with 3.5mm TRRS balanced headphone connectors)
- Direct jack: Intended for regular-sensitivity headphones
iEMatch® jack: Incorporates iFi’s signature iEMatch® circuit to match high-sensitivity IEMs/headphones for reduced background noise and matched gain.
- Rear panel: One 3.5mm line out jack
- Digital formats and data rates supported:
DSD: 256/128/64 at rates of 24.6/22.6/12.4/11.2/6.2/5.6/3.1/2.8 kbps
DXD: 384/352.8 kHz
MQA: 88.2/96/176.4/192kHZ filters
- Filters: Nano iDSD filter settings are context-sensitive, depending on the type of digital audio file being played, as shown below
- PCM: two switch-selectable digital filters (Listen/Measure)
Listen (transient optimised, minimum phase)
Measure (frequency response optimize)
- DSD: two switch-selectable analogue filters (Listen/Measure)
Listen (extended bandwidth, transient optimized)
- Measure (narrow bandwidth, low output band, noise optimized)
DXD: fixed analogue filter (fixed Bit-Perfect Processing)
- MQA: (fixed MQA filter)
- Jitter (correlated): Below test set limit
- Maximum Power Output (<10% THD): Direct output jack:
20mW @ 600 Ohms
285mW @ 30 Ohms
200 mW @ 15 Ohms
- Dynamic Range (including DAC): >109dB(A) @ 3V Direct output jack
>107dB(A) @ 0.5V iEMatch® output jack
- Distortion: < 0.005% THD + Noise @ 125mW/30 Ohms
- Controls: Front Panel:Rotary volume control and on/off switch
Rear Panel:Filter control switch with Listen and Measure settings
- Dimensions (H×W×D): 25.5 ×64 ×96 mm
- Weight: 139 grams
- Price: £200, or $199 in the U.S.
Manufacturer Information: iFi Audio
Distributed by: Select Audio
Tel: +44(0)1900 601954